Table of Content

31 December 1998, Volume 19 Issue S1

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Plenary, Keynote and Invited Lectures

Nature's Strategy for Making Unusual Sugars

Hung-wen Liu

1998, 19(S1):  1-1. 

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The deoxy sugars are an important class of carbohydrates that are derived from common sugars by the replacement of one or more hydroxyl groups with hydrogen atoms. Such a substitution generally causes a critical alteration of the biological role of the resulting sugar, and olso induces a fundamental change in the metabolic fate of the product. Particularly notable are the 3,6-dideoxyhexoses found in the lipo-polysaccharides of gram-negative bacteria and the 2,6- and 4,6-dideoxyhexoses found in many bioactive secondary metabolites. Intrigued by the great variety of the biological activities and structural features of deoxy sugars, we have undertaken an investigation into the biosynthesis of this important class of molecules. In the past few years we have focused our efforts on the formation of ascarylose, a 3,6-dideoxy sugar, and other related deoxy sugars from Yersinia pseudotuberculosis. The first part of this presentation will cover the establishment of the course of each multi-step biotransformation and the characterization of the key enzymes involved in this pathway.

The Development of "Caged" Substrates for the Studies of Rapid Electron Transfer and Early Events in Protein Folding

Sunney I. Chan

1998, 19(S1):  2-2. 

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In recent years,the applications of photolabile compounds, or compounds that unmask a function group upon absorption of light, have become more diverse. Since such compounds can provide an effective means of orthogonal protection, they have been used to facilitate the synthesis of complex, polyfunctional organic molecules. These materials have also been used to "cage" compounds by protection of an essential functional group, so that a chemical reaction may be initiated by a pulse of light. In this manner, mixing difficulties can be circumvented in kinetics measurements. Applications of this method include the photolysis of caged ATP for studies of muscle fiber contraction, where diffusion of ATP into the muscle fiber is, slow; of caged fluorescent probes that only emit light after photolysis; and even of caged enzymes by incorporating photolabile groups on essential side chains.

Opportunities In Interfacial Area Between Organic and Materials Chemistry

Luping Yu

1998, 19(S1):  3-4. 

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It is well recognized that the current trend in organic chemistry is diverged into two frontiers: biochemistry and materials chemistry. This talk presents our recent research effort in the interfacial area between organic and materials chemistry. The major theme of our research is focused upon the rational design, synthesis and characterization of novel functional and multifunctional polymers and molecules. Typical examples of current projects are: 1). Development of polymerization methodologies: a). exploration of palladium catalyzed reactions for polycondensations, b). living ring-opening polymerization of cyclic lactone to form thioester-functionalized polyesters for chemo-ligation, 2). Design, synthesis and physical studies of photorefractive polymers, 3). Second order nonlinear optical polymers, 4). Conjugated diblock polymers for the formation of self-assembled, nano-sized electroactive materials, 5). High-performance light emitting diodes from new conjugated polymers, 6). Conjugated liquid crystalline polymers, 7). Architectural controls of polymer microstructures, including synthesis of dendritic polyphenylenevinylenes, 8). Metal-containing functional polymers. 9) Biocompatible polymers.

Biotransformation In Enantioselective Synthesis of Optically Active Compounds

Lin Guo-qiang

1998, 19(S1):  7-8. 

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Transformation catalyzed by enzymes and microorganisms (biotransformation) is now well recognized as valuable tool in preparation of chiral intermediates. In this presentation the microbial reduction by G38, a fungus isolated from soil, PPL catalyzed acylation of a meso-diol and synthesis of (R)-cyanohydrins by (R)-oxynitrilase under microaqueous medium were described.

Recent Progress in the Synthetic Applications of Substituted Furans and Pyrroles

Henry N. C. Wong

1998, 19(S1):  9-9. 

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In this lecture, I would like to present efficient synthetic routes towards the total synthesis of syringolide 1 (2)^1,2 and secosyrin 1 (3),¹ employing 2,4-disubstituted furan 1 as a common precursor. A modified total synthesis of prehispanolone (6)³ from (S)-(+)-Wieland-Miescher ketone (4) via hispanolone (5) will also be discussed. Our methodology for the synthesis of 3,4-disubstituted-lH-pyrroles⁴ and for the generation of 3,4-didehydrothiophene⁵ has also guided us to the successful identification of 1-tert-butoxycarbonyl-3,4-didehydro-1H-pyrrole (7),which is presumably the most strained heterocyclic cumulene ever recorded.

Total Synthesis of (-)-α-Pinguisene

Chin-Kang Sha, Pyng-Chang Cherng

1998, 19(S1):  10-10. 

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In previous work from our laboratory, we demonstrated that α-carbonyl radical cyclization reactions can serve efficiently as key steps in total synthesis of natural products.1 In this presentation,we report the total synthesis of (-)-α-pinguisene from enone 1 via α-carbonyl radical cyclization.

Development of (S)-Malimide as A Versatile Chiron for the Synthesis of 2-Pyrrolidinone-related Compounds

HUANG Pei-Qiang, ZHENG Xiao, TANG Xu, LIU Xiu-Ping, WANG Shi-Li, YE Jian-Liang

1998, 19(S1):  11-12. 

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Selectivity, efficiency and flexibility are three major goals in organic synthesis. A good flexible synthetic method would allow the preparation of different class of compounds as well as their homologous in a straightforward way. The development of flexible synthetic methodology is particularly important in view of both providing compounds for screening ligands, bioactive compounds, drugs candidates, agrochemical candidates, etc. and providing methods for combinatorial chemistry.

Combination of electrochemistry and the concurrent reduction and substitution chemistry to provide a facile and versatile tool for preparing functional polyanilines

Chien-Chung Han, Wen-Da Hseih, Jiann-Yeh

1998, 19(S1):  13-13. 

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Polyaniline as the first commercially available conducting polymer has recently received great attention from both academic and industrial communities. Although there have been quite a few reports on substituted polyanilines, none of them are concerning about the amino- and alkylthio-substituted polyanilines. Unlike other substituted polyanilines, the attempts in synthesizing poly(alkylthioaniline) directly from the alkylthioaniline monomer via chemical and electrochemical oxidative-coupling chemistry were all fail. On the other hand,we have recently discovered that the amino and alkylthio functional groups can be easily introduced to the backbone of emeraldine polyaniline via the concurrent reduction and substitution chemistry. Further combination of electrochemistry and the concurrent reduction and substitution chemistry can provide us a facile and versatile tool for preparing functional polyanilines. Different functional groups can be introduced sequentially to the same polymer backbone. The concentrations of each substituents can be easily controlled. This new process provides us a useful utility for tailoring the molecular and the electronic structures of polyanilines to render them with appropriate and possibly new material properties suitable for many different potential applications.

Theoretical Studies of β-Peptide Models

Yun-Dong Wu, De-Ping Wang

1998, 19(S1):  14-15. 

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Recently, the β-peptides, which consist entirely of β-amino acids instead of α-amino acids, have received intensive attention because of their interesting secondary structures.^1-3 Depending upon side chain substitution pattern, β-sheets, 14-helices, and 12-helices all have been observed.¹ Due to great variety of substitution patterns,the easiness of formation of secondary structures with even 4-6 residues compared to about 15 for natural peptides,and ready formation of cyclic compounds that stack into tube structures,⁴ β-peptides have generated great excitement. In addition,β-amino acids also frequently occur in natural products, especially cyclic peptides. It has been found that β-amino acids have excellent stability toward proteases. Therefore, they have wide applications in drug development.⁶

Asymmetric Synthesis of Natural Eudesmane Acids

Yulin Li, Zhaoming Xiong

1998, 19(S1):  16-17. 

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Eudesmane derivatives constitute a group of natural compounds widely distributed in the plant kingdom. These kinds of compounds exhibit considerable biological activities such as antifeedant,cell growth inhibitory and plant growth regulating activities,¹ and consequently efficient synthesis of those compounds are a synthetic challenge that has received much attention in the past decades. In recent years a number of eudemane acids have been isolated from natural sources.² However the synthesis of this particular kind of compound have received little attention. In association with our synthesis work on eudesmane-type sesquiterpenes, we have been interested in studying on the synthetic approaches to this kind of compound, in particular the synthesis of compounds 1-6.

Cooperative Binding Behavior of Ureyleno Compounds

Man-kit Leung

1998, 19(S1):  18-18. 

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Since the discovery of crown ethers few decades ago, the synthesis and chemistry of macrocyclic compounds has attracted considerable attention due to their unusual ability to act as hosts to both neutral and ionic species. The study of host-guest phenomenon provides fundamentals of understanding about enzyme-substrate interactions in biological systems. Recent investigations disclosed that the binding power of a host is governed by the size, the shape, the rigidity, and the noncovalent interactions of the cavity. Important is the fact that highly flexible hosts often make binding entropically unfavorable. To tune the binding ability of a host, one should carefully design the host with appropriate rigidity. Despite of the fact that urea units and cyclic derivatives thereof are known to possess powerful ligating abilities which are due primarily to their highly polarized carbonyl groups, macrocycles incorporating urea as the binding groups have received limited attention compared to their polyoxa, polyoxo,and polyaza congeners.

Ketone Catalyzed Oxidation Reactions

Dan Yang

1998, 19(S1):  19-19. 

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Dioxiranes are important oxidants for organic reactions such as epoxidation, heteroatom oxidation and oxygenation of C-H bonds. We have developed a mild and general method for epoxidation of olefins using dioxiranes generated in situ from ketones and Oxone. This method has not only extended the synthetic utility of dioxiranes, but also allowed us to discover a series of novel cyclic ketones for catalytic oxidation. In particular, we have demonstrated the potential of chiral ketones for catalytic asymmetric epoxidation of trans-olefins and trisubstituted olefins. We have also explored the potential of ketones in catalyzing oxidation of unactivated C-H bonds and decomposition of peroxynitrite.

Bile Acid Derivatives in the Preparation of New Synthetic Polymers

X. X. Zhu, H. Y. Liu, A. Benrebouh, S. Gouin, Y. H. Zhang

1998, 19(S1):  20-20. 

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Bile acids are compounds stored in the gallbladder and help in the digestion of fats and lipids in the gastro-intestinal tract. These amphiphilic compounds can interact favorably with both hydrophilic and hydrophobic molecules. To improve the biocompatibility of the polymers used in biomedical and pharmaceutical applications, we have synthesized various derivatives of bile acids and used them in the preparation of new polymeric materials, including both polyaddition and polycondensation products. The use of the bile acid derivatives should improve the biocompatibility of the polymers, especially when they are used in the gastrointestinal tract. Even in case of decomposition, these derivatives are not expected to cause serious problems of toxicity. We have used bile acids in the preparation of both stable polymers (hydrogels) and degradable ones (polyanhydrides).

Attractive π-Interaction as an Efficient Control Element for Acyclic Stereocontrol

Teck-Peng Loh

1998, 19(S1):  21-22. 

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During the course of our synthetic studies of a natural product, an indium-mediated allylation reaction in aqueous media has been developed as the key step for the assembly of the advanced intermediate 2 (Scheme 1) in our strategy. The reaction proceeds with very high diastereoselectivity (>99% de), a result rare for acyclic molecules in the absence of obvious steric interaction or intramolecular chelation.¹ The interlocking physical, chemical and computational studies undertaken supported a π-stacking effect between the phenyl ring with the ketone.

C₂, Symmetric Dibenzosuberanes as Templates for the Chirality Determination of Helicenes and Their Applications as Optically Switchable Memory Device

Y. C. Chou, J. I. Gao, C. T. Chen

1998, 19(S1):  23-24. 

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We have recently developed a new type of chiral templates, dibenzosuberanes. Thess C₂, symmetric diaryl modifiers have been successfully applied to the synthesis of chiral triarylcarbenium ions. They can serve as catalysts in the asymmetric Mukaiyama aldol reactions with moderate enantioselectivities of up to 50% [1]. We have subsequently found that one major side reaction between the catalyst and the substrate-silyl ketene acetal which releases extra silyl-X species is responsible for the erosion of asymmetric induction. The dibenzosuberane scaffold was found essential to prevent this type of side reaction. For the selection of carbenium counter ions, we have resorted to the chloride in order to completely suppress the undesired silyl catalysis [2].

A Total Synthesis of RA-VII

Jieping Zhu

1998, 19(S1):  25-25. 

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RA-VII (1) and related bicyclic hexapeptides, isolated from Rubiaceous plants, Rubia akame,showed potent antitumor activity and in fact, RA-VII is currently undergoing phase Ⅱ clinical trial in Japan. It inhibit protein synthesis through binding,to eukaryotic 80S ribosomes, resulting in inhibition of aminoacyl-tRNA binding formation and peptidyl-tRNA translocation. The complex molecular architecture and interesting biological activity made these compounds attractive synthetic targets.

Development of Methods for Diastereo- and Enantioselective Synthesis of Hydroxyl amine Derivatives

Kang Zhao

1998, 19(S1):  26-26. 

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N-alkyl hydroxylamines add to conjugated alkenoates in a "concerted" fashion with high stereoselectivity and the esulting intermediates can be easily derivatized to several classes of biologically interesting molecules such as the analogs of aminosugar and nucleoside. For example, high stereoselectivity was observed in the addition of hydroxylamine derivatives to acyclic a,b-unsaturated esters. The adducts were subsequently cyclized under mild conditions to afford a single isomer of isoxazolidin-5-ones which were converted to class of isoxazoline and isoxazolidine derivatives for the studies of their antiviral activity.

Green Chemistry and Glycochemistry

Peng George Wang

1998, 19(S1):  27-28. 

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With the increasing environmental concerns and the regulatory constraints faced in the chemical and pharmaceutical industries, development of environmentally benign organic reactions (also called Green Chemistry) has become a crucial and demanding research area in modem organic chemical research. Our contribution to this rapidly growing field involves use of certain lanthanide salts such as lanthanide(Ⅲ) trifluoromethanesulfonates as stable Lewis acids in protic solvent such as water or alcohols to catalyze a variety of organic transformations under nearly neutral conditions. This benign approach has the potential to replace many traditional reaction systems which are either conducted in strong acidic conditions or in environmentally less-friendly solvents. For example, aza Diels-Alder (DA) reaction in aqueous solution conveniently combines three reactant components (an aldehyde, an amine salt and a diene) in aqueous solution and generates nitrogen-containing heterocyclic products. However, this reaction is limited to either the smallest aldehyde or activated aldehydes such as glyoxylates. We have found that lanthanide(Ⅲ) triflates catalyze the aza DA reactions of a larger,inactivated aldehyde and an amine hydrochloride with a diene in aqueous solution[1]. Other examples of application of lanthanide triflates in protic solvents include Chicliibabin pyridine synthesis[2],condensation of indoles with aldehydes or ketones[3], and use of ion-exchange resin supported lanthanide catalysts[4].

Organic Synthesis Chemistry

A Straightforward Synthesis of Polythiophene-fused-3-sulfolenes from Methyl 3-Hydroxy-4,6-dihydrothieno[3,4-b]thiophene-2-carboxylate

Hsi-Hwa Tso, Honru Tsay

1998, 19(S1):  29-29. 

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A straightforward synthesis of substituted polythiophene-fused-3-sulfolenes from the readily prepared methyl 3-hydroxy-4,6-dihydrothieno[3,4-b]thiophene-2-carboxylate will be presented. Upon thermolysis in the presence of N-phenylmaleimide, these new substrates serve as precursors of reactive polythiophene o-quinodimethanes to give the corresponding Diels-Alder adducts in high yields.

Efficient Transformation of Nitrile into Amide under Mild Condition

Manas K. Basu, Fen-Tair Luo

1998, 19(S1):  30-30. 

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Transformation of various kinds of nitriles into the corresponding amides or amide salts was performed in good yields by the addition of two equiv of chlorotrimethylsilane and three equiv of water at 0℃ to room temperature. Hydrogen halide generated in situ by TMSX and water is an important reaction especially when HX is needed in requisite amount and under dry reaction conditions. As part of our endeavor to utilize HX thus generated, we have found TMSC1 and water can be used for transformation of nitriles into amides under very mild reaction conditions and with satisfactory yields. Interestingly, under the condition of hydration of nitrile, ester of carboxylic acid remains intact. Although there are several reports in the literature to bring about the same transformation, however, a new approach is still significant and needed. Moreover, most of the reported methods have not been proven in general and practical in scope. This paper reports the hydration of a series aliphatic as well as aromatic nitriles into amides at 0℃ to room temperature for only two to four hours. Solvent is not needed in this transformation. Attempts to use THF, MeNO₂, or CH₂Cl₂ as the solvent results in poor yields. Protonation of the nitrile by HCl, generated in situ from TMSC1 and half equiv of H₂O, and followed by nucleophilic attack by another equiv of H₂O to form the amide salt seems to be the possible pathway for this reaction. Ideally, the molar ratio for RCN/TMSC1/H₂O is 1:1:1.5. Use of little excess of the reagents (0.2 to 0.5 equiv) leads to completion of this reaction in 10 to 12 h. To compensate the escape of HCl generated in situ, one more equiv of HCl is generally used in this reaction. No further hydrolysis of amide to the carboxylic acid was observed in the presence of one more equiv of water.

Misenine,a Novel Macrocyclic Alkaloid with an Unusual Skeleton from the Mediterranean Sponge Reniera sp

Yuewei Guo, Enrico Trivellone, Gennaro Scognamiglio, Guido Cimino

1998, 19(S1):  31-32. 

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PolycycJic marine alkaloids containing 3-alkylpyridine or partially reduced 3-alkylpyridine as basic building blocks represent an emerging and intriguing group of bioactive natural products from marine sponges. Since halitoxin,² the first example of this kind of alkaloid, was reported in 1978, many related alkaloids have been discovered from sponges of the order Haplosclerida. All of these alkaloids, in spite of formally exhibiting quite different frameworks, could biogeneticaliy derive from bis-3-alkylpyridine or reduced bis-3-alkylpyridine units. In the last decade, the knowledge of this fascinating group of compounds has increased remarkably. A recent review has exhaustively studied occurrence, distribution, plausible biogenetic origin and relatedness, as well as biological activities, of 3-alkylpyridine derived marine alkaloids.³

A Novel Rearrangement Cyclization of 3-Amino-2-benzyl-6-hydrazino-1,2,4-triazin-5-one

Long-Chih Hwang

1998, 19(S1):  33-33. 

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A facile ring closure reaction with the N-l nitrogen of the 1,2,4-triazine ring occurs when 3-amino-6-hydrazino-1,2,4-triazin-5-one(1) is refluxed in either acid, orthoester/dimethylformamide, carbon disulfide, cyanogen bromide or nitrous acid. 3-amino-2-benzyl-6-hydrazino-1,2,4-triazin-5-one(2), containing the benzyl group on the 2-position of 1, can not be cyclized under the above reaction conditions except refluxed with carbon disulfide in pyridine-water(1:1), which will pass through a novel rearrangement cyclization to afford a bicycloheterocyclic compound,6-amino-3-benzylmercapto-1,2,4-triazolo[3,4-f][l,2,4]triazin-8(7H)-one(3). The mechanisms of their ring closure and rearrangement cyclization will be presented in detail.

ENE REACTION WITH PUMMERER-TYPE REACTION INTERMEDIATE OF α-(METHYLTHIO)ACETIC ACID PYRROLIDIDE:SYNTHESIS OF ACHILLEA AMIDE AND TRICHONINE

Kuo-Hui Sun, Huey-Min Wang, Ling-Ching Chen

1998, 19(S1):  34-34. 

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The dienamide group is an important structural feature of a number of natural products, which have been reported to be biologically active, especially as insecticides. Several methods for their synthesis have appeared involving Wittig reaction, elimination reaction, and amidation of corresponding dienoic acids or esters. Achillea amide [(E,E)-2,4-tetradecadienoic acid pyrrolidide] and Trichonine [(E,E)-2,4-eicosadienoic acid pyrrolidide)] which are naturally occurring insecticides isolated from Achillea nana and P. trichostachyon leaves, respectively. Severál methods have reported successful syntheses of unsaturated pyrrolidine amides. In this work we wish to report that the Pummerer-type reaction intermediate 2 derived from α-(methylthio)acetic acid pyrrolidide (1) and phenyliodine(Ⅲ) bis(trifluoroacetate) (PIFA) undergoes an ene reaction with 1-alkenes to give the ene adducts 3. Also reported is its application to the synthesis of Achillea amide (4) and Trichonine (5).

Methoxide Promoted Anionic Cyclization of 2-Alkynylbenzonitrile:A New Synthesis of 3-Substituted Isoqunolin-1-one

Ming-Jung Wu, Li-Juan Chang, Chi-Fong Lin

1998, 19(S1):  35-35. 

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The treatment of 2-(2-alkylethynyl)benzonitrile with sodium methoxide in methanol gave 3-alkyl-l(2H)-isoquinolinone in modest yield. Under the same reaction conditions methanolysis of 2-(2-arylethynyl)benzonitrile lead to the formation of 3-alkylidene isoindol-1-one. Partially hydrolysis of 2-(l-hexynyl)benzonitrile to the corresponding benzamide,followed by the treatment of the benzamide with sodium methoxide gave 3-pentylidene isoindol-1-one in 11% yield. This result suggests that benzamide is not the intermediate of the formation of isoquinolinone. The more plausible mechanism of this methanolysis process is involving the iminium anion cycloaromatization to form 2-methoxyisoquinoline and subsequent hydrolyze to isoquinolinone. In one case,2-methoxyisoquinoline product was isolated.

A General and Facile Synthesis of l,3-Diaryl-4-pyrazoleacetic Acids and Its Application in the Synthesis of SDZ RGU 825

Daqiang Xu, Kapa Prasad, Oljan Repic, Thomas J. Blacklock

1998, 19(S1):  36-37. 

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1,3-Diaryl-4-pyrazoleacetic acids and derivatives exhibit multiple biological activities.¹ For example, Lonazolac^® is listed in Merck index as an antiinflammatory and analgesic agent. We were interested in this type of compounds for their potential applications in anti-diabetics. One of the leading candidates, SDZ RGU 825,has been shown to enhance whole-body glucose disposal without increasing insulin secretion. Therefore, it was developed for treatment of "non-insulin-dependent diabetes mellitus",the type Ⅱ diabetics.

A NEW Method for the Synthesis of Polyether Bridged Azulenes:Reactions of Conjugated Keto-carbenes in the Photolysis of the Corresponding Azulenoquinone Diazides

Yun-Shan Lin, Shuan-Ya Jiang, Shih-Jue Lin, Tian-Chuan Huang, Yuan L. Chow

1998, 19(S1):  38-39. 

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Photolysis of 1,4-quinone diazides has been known to generate conjugated keto-carbenes that may exist in the triplet and singlet states of ground as well as lowest excited levels with energy levels closely packed to one another. We used the diazides of 1,3-disubstituted 2,4-azulenoquinones as the model compound to demonstrate their singlet state reactivity in electirophilic reactions in competition to other reactions. Under the optimum conditions, the keto-carbenes reacts with cyclic ethers or amines repetitively to give polyether bridged azulene derivatives.

OXIDATION OF HYDROCARBONS UNDER THE MILD CONDITIONS

Yasuhiko KURUSU

1998, 19(S1):  40-41. 

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The oxidation of organic substrates leads to the production of many functionalised molecules which are of great commercial and synthetic importance. The conventional mode of oxidation which involves stoichiometric ammount of Cr or Mn salts has been staked out because of the environmental hazadrous process. The transition to cleaner, safer, and more efficient plants is a new paradigm in the synthetic organic chemistry. Nowadays, hydrogen peroxide and oxygen as oxidizing agents were extreamely valuable and attractive. It is increasingly recognized, when polymers are used as supports for catalysts or organic reagents, the reactivity and selectivity of the supported catalysts or reagents may be seriously changed by so-called "polymer effects". As metal catalyzed oxidation of organic substrates with oxygen, we arc planing the incorporation of transition metals into polymer. In oxidaton organic compound has little resistant, so syntheses of organic-inorganic hybrid polymer from silica gel and montmorillonite by the modification with silane coupling reagents and the complexation of transition metal ions into hybrid polymer obtained above were investigated.

Regioselective Formation of Enediynes via Intramolecular Trapping of Allylic Cations

DAI Wei-Min, LEE Mavis Yuk Ha

1998, 19(S1):  42-43. 

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Enediynes are a novel class of naturally occurring antitumor antibiotics capable of causing DNA strand cleavage by hydrogen atom abstraction from the deoxyribose backbone. During the past decade, numerous synthetic methods have been developed to synthesize the naturally occurring and the "designed" enediynes for biomedical studies. Recently, we have succeeded in assembling the cis-enediynes 2 by a novel and high-yielding allylic rearrangement under mild reaction conditions (Eq 1).^1-3 This methodology has been used to synthesize a 10-membered ring enediyne³ which exhibits DNA cleavage activity.

Preparation of 2,6-Diisopropylnaphthalene(2,6-DIPN) by the Shape-Selective Isopropylation of Naphthalene over Synthetic Mordenite

TIAN Zheng-Hua, WANG Wen-Han, ZHANG Xiao-Hui, SONG Ren-Feng

1998, 19(S1):  44-45. 

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2,6-DIPN is a precursor of 2,6-naphthalene dicarboxylic acid (2,6-NDA) which is an important monomer for making advanced polyester materials and liquid crystalline polymers. The more advanced method for preparing 2,6-NDA is the direct oxidation of 2,6-dialkylnaphthalene (2,6-DAN). Since isopropyl group is more hindered than methyl and ethyl group, a β-selective isopropylation could be expected in case of using shape selective zeolite catalysts instead of the conventional Friedel-Crafts alkylation. A particularly preferred catalyst is synthetic Mordenite having a specific Si/Al ratio, which results in a high selectivity of 2,6-DIPN. It is more beneficial to the separation and purification of 2,6-DIPN from its isomers. In this paper the study on isopropylation of naphthalene over various zeolites and different dealuminated H-mordenites (HM) is reported.

Production and Study of Monoclonal Antiidiotypic Antibody with a Catalytic activity similar to Carboxypeptidase A

DU Mei, JIN Sheng, GUO Zheng quan

1998, 19(S1):  46-47. 

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Catalytic antibody(abzynie) is a new class of biocatalysts. Combining the specificity and the enormous molecular diversity of the antibody with high catalytic efficiency of enzyme to produce catalytic antibody, that is a new method of designing protein. A method of producing catalytic antibody developped recently is to produce antiidiotypic antibody. As the "internal images" of the antigen structure, the antiidiotypic antibody can exhibit the properties similar to the antigen¹. To produce the antiidiotypic antibody of the natural enzyme, we may obtain the catalytic antibody whose structure and catalytic activity are similar to the natural euzyme. A. Friboulet et al successfully produced the antiidiotypic catalytic antibody of acetylcholinesterase, whose catalytic activity approaches the natural acetylcholinesterase². Carboxypeptidase (CPA) has peptidase and esterase activities, to produce the antiidiotypic antibody of CPA, we may obtain the catalytic antibody which catalyze the hydrolysis of amide bond and highly efficiently catalyze the hydrolysis of ester bond. Therefore, this research work is very significant. In this report, we produced a monoclonal antiidiotypic antibody with a catalytic activity similar to the esterase activity of CPA and studied it's kinetic property.

Direct Trapping of Ketene Intermediate by Internal Nucleophile:A New Approach for the Synthesis of γ-Lactams

Yihua Hou, Jianbo Wang

1998, 19(S1):  48-49. 

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The application of Wolff rearrangement of the diazoketones derived from α-amino acids has been well documented.¹ It has been generally observed that if the rearrangement is performed in aqueous solution, homologated acid is the expected products, while if the reaction is run in methanol or ammonia, the corresponding homologated ester or amide will be obtained. In connection with other synthetic work, we unexpectedly observed that the Wolff rearrangement of diazoketone 1 in anhydrous methanol gave exclusively γ-lactam 3 in excellent yield.(Scheme 1) The formation of this intramolecular cyclization product was apparently due to the nucleophilic attack of the intermediate ketene 2 by the tosyl protected amino group. Although the solvent methanol can serve as nucleophile, the exclusive formation of γ-lactam indicates the intermolecular nucleophilic attack of the ketene intermediate 2 by methanol is not effective enough to compete with intramolecular nucleophilic attack by the tosyl protected amino group. This observation aroused our interest in the generality of this reaction and its potential as a novel method for the direct synthesis of γ-lactams. We report here the results of the investigation of Wolff rearrangement of several diazoketones derived from N-tosyl protected α-amino acids and β-amino acids.

A Linear Free Energy Correlation Study of Rh(Ⅱ)-Mediated Carbenoid Intramolecular C-H Insertion

Fengting Liang, Bei Chen, Jianbo Wang

1998, 19(S1):  50-51. 

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The reaction mechanism of Rh(Ⅱ)-mediated carbenoid intramolecular C-H insertion have been intensively investigated. The reaction has been observed to be affected by the electrophilicity of the Rh(Ⅱ)-carbene intermediate, the substituents on the carbon at which the C-H insertion occurs, and steric and conformational factors.¹ It has been well documented that the electronic property of the ligands of the Rh(Ⅱ) catalyst has marked influence over the electrophylicity of Rh(Ⅱ)-carbene intermediate. In addition, the α-substituent on the carbenoid carbon are expected to exert similar affect on the reactivity of Rh(Ⅱ)-carbene. According to the reaction mechanism proposed by Doyle, an electron-donating α-substituent decreases the electrophilicity of the Rh(Ⅱ)-carbene complex and causes the C-H insertion to occur with a later transition state,while an electron withdrawing α-substituent operates in the opposite way. However, this prediction is still lack of solid support by experimental data. Most of the studies on the electronic effects have so far been concentrated on electron-withdrawing α-substituent, such as ester or acetyl group. The α-substituent effect, although important, is generally subtle and may be readily overridden by other effects, such as steric and conformational effects. This makes it difficult to accurately evaluate the α-substituenteffect.

Study on the Non-enzymic Catalytic Enantioselective Methanolysis of 4-benzyl-2-phenyl-5(4H)-oxazolone

Wenting Hua, Lunjia Xie

1998, 19(S1):  52-53. 

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Dynamic-kinetic resolution is different from kinetic resolution¹. In ideal case,dynamic-kinetic resolution can convert racemic substrate to product with 100% yield and >99% e.e. whereas kinetic resolution can only converted racemic substrate to enantiomeric pure product with 50% yield.

Synthesis and Characterization of Macrocycles Containing 1,3,4-Oxadiazole

Wenting Hua, Shu Wang

1998, 19(S1):  54-55. 

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The design of molecules with delocalized π-electronic structures which are useful as organic conductor and light-emitting diodes(LEDs) has attracted much attention.^[1-2] We have synthesized some conjugated Schiff base macrocycles containing 1,3,4-oxadiazole(such as compound 1) and after being doped with I₂,they showed electrical conductivity in the region of semiconductor.^[3] To continue this work and understand the relationship between molecular structure and solid state properties, we designed other conjugated schiff base macrocycle containing 1,3,4-oxadiazole.

Application Studies of Antigenic Peptides

Jiaxi Xu

1998, 19(S1):  56-57. 

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The region of an antigen that is recognized by a paratope is called an antigenic determinant or epitope. Antigenic peptide presented epitope is very important to many fields, such as detecting diseases, developing synthetic peptide vaccines. Herein we reported antigenic peptide applications in HEV diagnosis, protein detection in gene expression product of transgenic tobacco and synthetic peptide vaccine against schistosomiasis.

ASYMMETRIC ADDITION OF (+)-CAMPHOR SULFINIMINES WITH DIETHYLALUMINUM CYANIDE

Li Yan, Zhu Wei, Cheng Zhi-Yong, Yang Gui-Shu

1998, 19(S1):  60-61. 

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The development of new and improved methods for the asymmetric synthesis of α-amino acids is of considerable current interest because of their importance in biological systems and their exceptional utility as chiral building blocks. Of the many methods used to prepare α-amino acids, the asymmetric Strecker synthesis should hold particular prominence because of its simplicity¹. Recently, F. A. Davis and his coworkers reported that diethylaluminum cyanide (Et₂AlCN) adds to enantiopure p-tolylsulfinimines to give α-sulfinamino nitriles at 82-84% diastereoselectivity. Treatment of α-sulfinamino nitriles with acid removes the chiral auxiliary p-tolylsulfinyl group and hydrolyzes the nitrile to give α-amino acids without epimerization². This research was quoted in Highlight by Chemistry & Industry as an improved asymmetric Strecker synthesis³. However, the diastereoselectivity of this addition reaction needs to be improved more high, and moreover, the preparation of p-tolylsulfinimines from nonracemic p-tolylsulfinamides and aldehydes needs strong organic metallic bases^2b, so it is desirable to design an easier prepared and effective optical sulfinimines.

The Synthesis of 1,3-Dithiole Derivatives by Using Bun₃P·CS₂ Adduct

Xiaodong Chen, Yuxiu Liu, Ruzhen Cao, Lunzu Liu

1998, 19(S1):  64-65. 

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The red crystalline adducts formed between trialkylphosphines and carbon disulfide were confirmed to be l,3-dipolar structure by X-ray diffraction in 1961.^[1] Despite the apparent synthetic potential of the 1,3-dipolar structure, studies on its cycloaddition have only been restricted in electron-deficient alkynes as dipolarophiles.^[2-5] However, reactions with electron-rich alkynes have received little attention.

Cycloaddition of Bun₃P·CS₂ with Azo Compounds

Xiaodong Chen, Yuxiu Liu, Ruzhen Cao, Lunzu Liu

1998, 19(S1):  66-67. 

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Cycloadditions of Bun₃P·CS₂ Ⅰ with electron-deficient alkynes have been studied, but reactions with double bonds have only been confined to maleic anhydride, N-phenylmaleimide^[1] and norbomene analogs^[2]. In this paper we describe the first examples of cycloadditions of Ⅰ to heteroatom double bonds.

Synthesis of 2-ethyl-3-Hydroxy-4-Pyridone Nucleosides

Chen Weimin, Zeng Longmei

1998, 19(S1):  68-69. 

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The hydroxypyridones were found to have wide biological activities such as they can be used as iron chelators for the treatment of iron overload of transfusion-dependant patients^[1]. Some hydroxypyridones were discovered to possess moderate reproducible activity against murine P-388 leukemia^[2] and showed antimalarial activity^[3]. Besides some nucleoside of hydroxypyridones exhibit antitumor activity^[4]. The 2-ethyl-3-hydroxy-4-pyridone nucleosides were synthesized by direct condensation of the silylated 2-ethyl-3-hydroxy-4-pyridone with 1,2,3,5-tetra-o-acetyl-β-D-ribofuranose using trimethylsilyl triflate(Me₃SiOTf) as catalyst. Deblocking of the protected ribofuranosyl nucleosides was performed by the standard methods.

The Synthesis and Crystal Structure of Triphenyltin-2-(l,1-dithioalkyl)methylene-3-oxo-5-aryl-4-pentenicate

Sun Zhen-gang, Li Jian-xin, Liu Qun

1998, 19(S1):  72-73. 

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Triorganotin compounds are a kind of organotin complexes with high biological activities. Some of triphenyltin derivatives such as triphenyltin acetate and triphenyltin hydroxide have been used as agricultural chemicals^[1]. α-Oxo ketene dithioacetals is a kind of important polyfunctionai intermediates in organic synthesis and is widely studied in recent years^[2]. Some of α-oxo ketene dithioacetal derivatives, such as 1,3-dithio-2-cyclopentylene-dithiopropylacrylate has also been used as agricultural chemicals. But it is no reports about the work combined both trialkyltin derivatives and α-oxo ketene dithioacetals together.

Facile Total Synthesis of Three Natural 1,7-Diaryl-4-hepten-3-ones

Chusheng Huang, Xihui Chen, Yulin Li, Hongxing Liu

1998, 19(S1):  78-79. 

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Linear 1,7-diarylheptanoids (Ar¹-C₇-Ar²) are a large group of interesting natural products isolated from plants belonging to Alinia,Curcuma, Zingiber, Alnua,Centridobium and Acer genera used as traditional medicines in some oriental countries¹. Pharmacological experiments exhibited that some of them had many physiological actions such as anti-inflammatory, antifungicial, antioxidative,antihepatotoxic activities and so on². Three natural compounds 1³, 2⁴ and 3⁵ (gingerone C) having 1,7-diaryl-4-hepten-3-one skeleton were isolated from the rhizomes of Alpinia offocinarum, the wood of Alnus japonica and the rhizomes of Zingiber officinale respectively. Their structures were elucidated as 1,7-diphenylhept-4-en-3-one(1), 1,7-bis(4-hydroxyphenyl)hept-4-en-3-one(2) and 1-(3-hydroxyl-4-methoxyphenyl)-7-(4-hydroxyphenyl)hept-4-en-3-one(3) by spectral method. Herein, we wish to report facile total synthesis of these three natural compounds. Their synthetic routes were shouwn in scheme.

Facile Synthesis of (±)-2,6-Dimethethyl-6-hydroxy-2,7-octadienoic Acid and its Methyl Ester and Amide (Acacialactam)

Chusheng Huang, Xihui Chen, Ying Li, Yulin Li, Hongxing Liu

1998, 19(S1):  80-81. 

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The monoterpenoid acid 1, which is a component of some traditional medicine such as Gymnocladus chinensis baillon in glycoside form,¹ was recently isolated from Artemisia sieberi in Iran in free form.². Its structure has been established to be (E)-2,6-dimethyl-6-hydroxy-2,7-octadienoic acid (1) by chemical and spectroscopic analysis. Its methyl ester derivative 2,was isolated from the antibacterial extracts of the leaves of Piper aduncum³ as well. Acacialactam, a natural product isolated from the seeds of Acacia concinna DC.(Legunninosae) used in folk medicine of several tropical countries for treating some skin diseases, was assigned structure 4 by Sekine et al⁴ on the basis of its physical and spectral properties.

Study on the Synthesis of Poly(p-Phenylene Vinylene) Derivatives by Dehydrochlorination

Jianying WANG, Yinkui Li, Wenxiang HU, Yongfu LONG, Guangyou ZHANG

1998, 19(S1):  82-83. 

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The synthesis of poly(p-phenylene vinylene) (PPV) and its derivatives have aroused great interest^[1],since Burroughes^[2] discovered that PPV showed excellent electroluminescent (EL) properties. The conventional polymerization reactions, such as dehydrochlorination reaction,Wittig reaction and et al, usually afforded insoluble and/or infusible PPV and its derivatives, which shows inferior mechanical properties. Though the precursor polymer route can circumvent the insolubility of PPV, the strategy needs muti-step reaction and high temperature which affords the low yield and other disadvantageous^[3]. So the synthesis of soluble PPV derivatives with high yield are very fascinating.

Synthesis of 1,4-Bis(chloromethyl) Benzene with Different Alkoxy-Substituents

Jianying WANG, Yinkui LI, Wenxiang HU, Yongfu LONG, Shengjian TAN

1998, 19(S1):  84-85. 

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l,4-Bis(chloromethyl) benzene (BCMB) and its derivatives are very important intermediates of much synthetic reaction. Especially, they can be used to synthesize poly(p-phenylene vinylene) (PPV) and its alkoxy derivatives, which have aroused significant interest in recent years^[l,2]. So people pays close attention to the synthesis of BCMB derivatives. There are several methods to synthesize BCMB derivatives, such as applying HCHO or (HCHO)n with concentrated hydrochloric acid or anhydrous HCl in the presence of zinc chloride, adopting (HCHO)n with hydrochloric acid in acetic acid aqueous, or utilizing HCHO reacts with hydrochloric acid and bubbles anhydrous HCl which was so called Wood method^[3].The methods mentioned above usually affored low yield of BCMB substituted by long alkoxy group, while the synthesis of BCMB with long alkoxy-substituents are the essential for the synthesis of soluble PPV derivatives^[4,5].

Synthesis And 3D-QSAR of Substituted Hydroxycarboxylates

Wenxiang HU, Momen LU, Yunzhang RAN, Liuhong YUN, Jianying WAN, G Jiaju ZHOU, Qian XIE

1998, 19(S1):  88-89. 

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Soman is a neural organophosphorus agent. The prophylatic and treatment of soman caused neural disease is very difficult. Hence research or discovery of potent antisoman drugs is very important in life science and the protective medicine against chemical weapons. Most of anticholinergic compounds are only muscarinic receptor antagonists with very weak affinity to nicotinic receptor. Therefore they have poor efficiency against soman poisoning.

A Convenient One-Pot Synthsis of Substituted Furans from Propargylic Dithioacetal

Chin Fa Li, Tien-Yau Luh

1998, 19(S1):  92-92. 

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The reactions of propargylic dithioactals with organocuprate reagent have recently been explored from our laboratory.¹ In this paper, we report the reactions of propargylic dithioactals 1 with organocuprate reagents followed by treatment with an aldehyde to afford the corresponding substituted furans 2.

Novel Oxidative Coupling of 2-Naphthols to 1,1'-Bi-2-naphthols Catalysed by Solid Lewis Acids Using Atmospheric Oxygen as Oxidant

Tong-Shuang Li, Hui-Yun Duan, Bao-Zhi Li, Brij B. Tewari, Sheng-Hui Li

1998, 19(S1):  93-94. 

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l,l'-Bi-2-naphthol derivatives have wide applications as chiral inducing agents for asymmetric synthesis.¹ There are many good methods for resolution of racemic binaphthols to give enantiomeric binaphthols.² Therefore, it is essential to established simple, convenient, economically and environmental-friendly methods for preparation of racemic l,l'-binaphthol derivatives. A number of methods have been developed for the oxidative coupling of 2-naphthols usually by using Fe³⁺, Cu²⁺ or Mn³⁺ as oxidants. The reaction were carried out in organic solvent,^3a in solid state^3b and in aqueous Fe³⁺ solution.^3c However, all those cases by employing excess, usually 2 equivalents of oxidant. The excess Fe³⁺, Cu²⁺ and the resulted Fe²⁺, Cu⁺ and HCl were not acceptable from a view point of environmental protection. Recently, Sakamoto et at⁴ and Kantam et at⁵ independently reported two catalytic oxidative coupling procedure for preparation of l,l'-binaphthols using aerial oxygen as oxidant and Cu²⁺-exchanged montmorillonite as catalysts. However, both procedures were by using some toxic chlorobenzene as solvent and long reaction time (>2 h) and high temperature(>140℃) were needed. Consquently, there is still a great demand for catalytic oxidative coupling 2-naphthols to generate binaphthols under mild conditions, environmentally friendly procedure and rapid process. Herein we report novel oxidative coupling of to 1,1-bi-2-naphthols (2a, 2b) catalysed by a number of supported reagents using aerial oxygen as oxidant. The results are listed in Table 1.

Unexpected Products from the Reaction of Naphthols with Cholesterol Catalysed by Montmorillonite K 10

Tong-Shuang Li, Li-Jun Li

1998, 19(S1):  95-96. 

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Under catalysis of montmorillonites, arenes could be cholesterylated by cholesterol (1) via a Friedel-Crafts alkylation.¹ When phenols were employed as substrates for that reaction, aryl cholesteryl ethers were obtained instead of aryl cholestenes.² However, β-naphthol (2a) and α-naphthol (2b) gave obviously different products. We report here the identification of these unexpected products from the reaction of 2 with 1 catalysed by montmorillonite K 10.

Novel Enone-benzene Rearrangement of 4,4-Dialkylcholest-5-en-3-ones to Ring-B Aromatic Steroidal Hydrocarbons Catalysed by p-Toluenesulfonic acid

Hui-Yun Duan, Tong-Shuang Li

1998, 19(S1):  97-98. 

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Under acidic conditions, α,α-dimethyl-β,γ-unsaturated cyclohexanones undergoes an enone-benzene rearrangement leading to aromatic derivatives^1-4. We recently run an enone-benzene rearrangement of 4,4-dimethyl-cholest-5-en-3-one (1a) catalysed by montmorillonite K-10 to give 1,3,4-trimethyl-19-norcholesta-1,3,5(10)-triene (2a) in moderate yield accompanying intractable mixture of hydrocarbons as by products⁵. Repetition of this reaction by employing TsOH as a catalyst, 2a was obtained in 65% yield and a new product, 6-methyl-3-isopropyl-A,19-dinorcholesta-6,8,10(5)-triene (3a), was also isolated in 25% yield. The formation of 3a has not been reported in earlier studies^1-5. Herein we report the novel enone-benzene rearrangement of 4,4-dialkylcholest-5-en-3-ones (1a~d) leading to ring-B aromatic steroidal hydrocarbons (3a~d) catalysed by TsOH (Scheme 1).

Synthesis of Allobetulin, 28-Oxyallobetulin and Related Biomarkers from Betulin and Betulinic Acid Catalysed by Solid Acids

Jian-Xin Wang, Tong-Shuang Li, Xue-Jing Zheng

1998, 19(S1):  99-100. 

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Betulin (1a) is an abundant natural product in the birch bark. Betulin itself currently has little usage. However, allobetulin (2a) has been used as an important intermediate in the further transformation of triterpenoids and as a sample for biological studies.¹ For example, allobetulin was further transformed to a highly active antifeedant for heliothis zea larvae. Some biomarkers (3a,b; 4a,b) with the same or similar structure as ring-E of 2a were identified in a brown coal.³ Consequently, the conversion of 1a to synthetically, biologically and geochemically more important 2a is of great significance. The transformation of 1a to 2a was reported as early as 1922 by Schulze et al in which betulin was isomerized by formic acid, involving formation and hydrolysis of allobetulin formate, to give 2a in moderate yield.⁴

Synthesis of Alkyl Bromide by the Method of Phase Transfer Catalysis

Chuanxin Zhang, Wanling Si, Baoguo Guo

1998, 19(S1):  101-102. 

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Phase transfer catalysis is one of the most active techniques used in organic synthesis^[1]. The process is versatile, fast, inexpensive, involves smooth work-up, give good yield and needs less drastic condition compared to conventional methods of synthesis. The technique has a very broad scope of application^[2], surprised, few are have been devised for synthesizing alkyl bromides. Alkyl bromides are important materials in organic synthesis and in agricultural chemical purpose, as well as widely used in the oil field gas exploration and water treatment^[3].

STUDIES ON THE CHEMICAL CONSTITUTIONS OF SONCHUS ARVENSIS L

Gui-Rong QU, Hong-min ZHANG, Xin-Ying ZHANG, Bai-Gen XIA

1998, 19(S1):  103-104. 

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Sonchus arvensis L. is one of perennial herbaceous plants of the composite family. It is abundant in China. It has the efficacy of for the treatment of fever, carbuncles and inflammation. Thirty-four compounds have been isolated and reported from the plant. In this paper, from the extraction of petroleum ether of sonchus arvensis L.,three chemical substances were isolated. By means of chemical and spectroscopic (IR, ¹H-NMR, ¹³C-NMR, ¹H-¹H COSY, MS) analysis, they were identified as n-hexacosanol (Ⅰ), α-amyrin (Ⅱ) and santoman (Ⅲ). Among them Ⅱ and Ⅲ are the first time isolated from this genus.

Fe₂(SO₄)₃·xH₂O CATALYTIC ESTERIFICATION OF MANDELIC ACID WITH ALCOHOLS

Hui Gong, Gui-Sheng Zhang, Huai-Zhou Li

1998, 19(S1):  105-106. 

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Mandelates have played an important role in organic synthesis and are used in artificial flavorings and perfumes. Mandelates may be prepared as follows:1). Direct esterification of mandelic acid with alcohols in the presence of sulfuric acid^1,2 or 2,2-dimethoxypropane and sulfuric acid;³ 2). Treatment mandelic acid and iodide in the presence of sodium hydrogen carbonate;⁴ 3). Treatment mandelic acid and alcohols with thionyl chloride.⁵ But these methods have some advantages and are not universally applicable. For example, the direct esterification catalyzed by sulfuric acid is not suitable for acid sensitive compounds and has the disadvantages of the corrosivity of strong acid and usually accompanying side reactions such as carbonization,oxidation, etherification, etc. We now reported the catalytic esterification of mandelic acid with a serious of alcohols using Fe₂(SO₄)₃·xH₂O as a new convenient catalyst.

A New Method for Preparing Amine Azo Compounds

Qing-zhi Zhang, Xie Fei, Shen-song Zhang

1998, 19(S1):  109-110. 

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In previous work, we have found that DMF is a good absorbent of NO₂, The resulting product DMF-NO₂ can be used as a mild and selective oxidant to oxidize acetals and oximes to corresponding aldehydes or ketones. Now,we find that it is also effective to covert substituted aniline compounds into corresponding amino azo compounds.

A SIMPLE, EFFICIENT AND NEW METHOD FOR PREPARING AZO UREAS

Cailan Wang, Yulu Wang, Xiaoyang Wang, Jianping Li, Hong Wang

1998, 19(S1):  113-114. 

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Azo compounds are widely utilized as dyes and analytical reagents.They can also be used as materials for non-linear optics and for storage optical information in laser dish^[1]. Recently, many noteworthy studies have shown that azobenzene derivatives possess excellent optical memory and photoelectric properties^[2]. The preparation of ordinary azo compounds has been described in many references. However, those compounds generally bear alkyl or aryl groups on both sides of the azo linkage (-N=N-).

Studies on Oxidation of Active α-H of Aromatic Hydrocarbon by CAN/NaBrO₃/H₂O System

Jian-Ge Wang, Guan Huang, Qi-Zeng Shi, Kun Cai

1998, 19(S1):  115-116. 

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Cerium ammonium nitrate (CAN) is an expensive and powerful selective oxidant. It has played an important role in organic synthesis. Because it is a single electron oxidant,many organic reactions need large quantities of it. The application of CAN in organic synthesis in the oxidation of alkyl aromatics has so far been limited. In this paper, we wish to report a new method of oxidation of active α-H of aromatic hydrocarbon by CAN/NaBrO₃/H₂O system. Only catalytic amount of CAN was needed in this method and the selectivity was improved as well.

The Synthesis of New Type Diazo Compounds by 4-hydroxy-2,2,6,6-Tertramethyl-1-Piperidinyloxy 1 as The Phases Transfer Dehydrogenation Catalyst

Xiao-Yang Wanga, Jian-Ping Li, YI-Yang Shenc, Hong Wang, Yu-Lu Wang, 'Zi-Yi Zhang

1998, 19(S1):  117-118. 

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It is well known that 4-hydroxy-2,2,6,6-tertramethyl-1-piperidinyloxyl is a stable nitroxyl radical. It can be used as antioxidants¹ and spin labeled compounds to mark protein, biomembrance and nucleic acid etc. Furthermore, as an efficient inhibitor, it can prevent olefin polymerizing by free radical. However, using 4-hydroxy-2,2,6,6-tertramethyl-1-piperidinyloxyl as the phase transfer catalyst has not been reported so far.

TRIMETHYLAMMONIUM CHLOROCHROMATE ADSORBED ON ALUMINA AS A NEW REAGENT FOR THE CLEAVAGE OF OXIMES AND P-NITROPHENYLHYDRAZONES

Gui-Sheng Zhang, De-Hong Yang, Mi-Feng Chen, Xiao-Yun Dang

1998, 19(S1):  119-120. 

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Derivatives of carbonyl compounds such as oximes and p-nitrophenylhydrazones have played an important role in the protection of carbonyl compounds,as they are highly crystalline and stable compounds. They are also very extensively used for the characterization and purification of carbonyl compounds. Regeneration of carbonyl compounds from their derivatives under mild condition is an important process in synthetic organic chemistry.

STUDIES ON SULFINATODEHALOGENATION:THE REACTION OF POLYFLUOROALKYL IODIDES WITH 4-PENTENOIC ACID COMPOUNDS

WU Fan-Hong, HUANG Wei-Yuan

1998, 19(S1):  121-122. 

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The radical addition of polyfluoroalkyl iodides to carbon-carbon multiple bonds is one of the most important and general methods for synthesis of a variety of fluorine-containing organic compounds.^[1] Studies in our laboratory on stulfinatodehalogenation reaction showed that sodium dithionite was a excellent initiation reagent for the addition of polyfluoroalkyl iodides, bromides and halocarbons to alkenes, alkynes and conjugated dienes effectively under mild conditions.^[2]

A Catalytic Enantioselective Synthesis of Biologically Interesting Cyclopropane Amines

Fu-Chang Shu, Chun-Xiao Xu, Qi-Lin Zhou

1998, 19(S1):  123-124. 

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The synthesis of cyclopropane amine has attracted considerable interest from organic chemists because of the biologically importance and its occurrence in numerous natural products¹. Several synthetic cyclopropane amines have been used as drugs, e.g. the monoamine oxidase inhibitor tranylcypromine (1)². However, it has been found that two enantiomers of chiral cyclopropane amine have different pharmacological effects³,which demands organic chemists to develop efficient methods to prepare them enantioselectively. Previous synthesis of enantiomerically pure cyclopropane amines involves resolution of racemic cyclopropane carboxylic acid followed by Curtius degradation⁴.

Reductive Coupling Reaction of Carbonyl Compounds In a TiCl₄/Ga Bimetal Redox System

Xiao-Lin Zhang, Ming Li

1998, 19(S1):  125-126. 

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For about 20 yeers the chemisty of low-valent titanium complexes has received great attention¹ and now many of the reactions involving them are commonly used in synethesis². The reactivity, of the low-valent titanium slurries, obtained after reduction of titanium trichloride or titanium tetrachloride by means of strong reducting agents such as magnesium, zinc in tetrahydrofuran has also been studied^3-4. In 1995,we reported that carbonyl compounds react with ethyl trichloracetate and iodoacetonitrile in a PbCl₂/Ga bimetal redox system⁵. Herein, we report reductive coupling reaction of carbonyl compound to afford E-alkenes with TiCl₄/Ga bimetal redox system. Simplicity of produre and moderate to excellent yields of product.

Synthesis, Chemistry and Applications of Heterocyclic Cage Compounds (V)

Chung-Yi Wu, Hui-Chang Lin, Chia-Hui Yen, Ching-FangYeh, Jyh-Haur Chern, Hsien-Jen Wu

1998, 19(S1):  127-128. 

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The synthesis and chemistry of polycyclic cage compounds have attracted considerable attention in recent years.¹ The vast majority of the work reported in this area has dealt with caybocyclic cage compounds. On the other hand, the synthesis and chemistry of heterocyclic cage compounds have received less attention. Recently, we have accomplished the synthesis of a series of oxa-cage compounds and performed the chemical transformations of these oxa-cage compounds.² As part of a program that involves the synthesis,chemistry and applications of heterocyclic cage compounds we report here the synthesis of heterocyclic cage compounds 1-12. We also wish to report the applications of compounds 7-12 on the π-facial selectivities. Studies on the cation-binding properties of compounds 1 and 2 and other oxa-cages are undertaken.

Synthesis and Structure-Activity Relationships of Anticholinergics of Dibenzo[b,e] oxepin(thiepin) Hydroxycarboxylates

Gao Shouhai, Yun Liuhong

1998, 19(S1):  129-130. 

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In order to investigate the relationships between the conformations of tricyclic hydroxycarboxylates and their anticholinergic activities, and to explore the effects of changing the linking groups between the two benzene rings in tricyclic compounds on anticholinergic activities and on the selectivity to the central nicotinic receptor, a series of new tricyclic anticholinergic compounds-dibenzo[b,e]oxepin (thiepin) hydroxycarboxylates (Fig. 1) were designed and synthesized.

Synthesis And Biological Activities of 4-Neoalkyl-2,6,7-Trioxa-1-PhosphabicycIo[2.2.2] Octanes

ShuXin LI, WenXiang HU, HuaTang XU, JianYing WANG, Shengian TAN

1998, 19(S1):  131-132. 

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4-Alkyl derivatives of 2,6,7-trioxa-1-phosphabicyclo[2.2.2] octanes are extensively used for spectroscopic studies and are candidates for use as flame retardants, vinyl resin stabilizers and antioxidants^[1-4]. Bicyclic phosphates are antagonist of GABA receptor, further research show that these compounds act on the chloride ion channel connecting with GABA receptor. So bicyclic phosphate can act as drugs to probe the Cl^- channel. Our preliminary pharmacological results indicate that these bicyclic phosphorus compounds should be handled with great care because of their high toxicity to mammals. Some derivatives of bicyclic phosphates have been prepared in our laboratory.

ACCELERATED APPROACH TO THE SYNTHESIS OF METHOXYCARBONYL-TERMINATED POLYETHER DENDRIMERS

LI Xiao-Hong, CAO Xiao-Ping, ZHOU Wei-Gang, NIE Kai-Sheng

1998, 19(S1):  133-134. 

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Dendrimers are macromolecules that radiate out from a central core, with the number of branch points on a given arm increasing exponentially from the core to the periphery.¹ Because of their novel properties, dendrimers have found many uses, including as unimolecular micelles, novel amphiphiles, and complexation agents.² These and other applications will benefit from more efficient methods of dendrimer preparation. The synthesis of dendrimer can be divided into both the divergent approach developed by Tomalia³ and Newkome,⁴ and the convergent method of Frechet.⁵ The convergent method was adopted in the synthesis of our target methoxycarbonyl-terminated polyether dendrimers. This method has the advantage over the divergent one in that the number of reaction in each step is restricted to a fixed small number irrespective of dendrimer generation, therefore completion of the reaction in each step can be controlled and monitored and large excess of reagent is not required even in the preparation of higher generation dendrimers.

The First Efficient Approach from α-(-)-Santonin to Dihydroagarofuran Sesquiterpene

Biangdong Sun, Yongqiang Tu, Wujiong Xia, Bin Wu

1998, 19(S1):  139-139. 

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The naturally occurring dihydroagarofuran compounds have been demonstrated to show some important bioactive activities, such as insect antifeedant, antitumor activities.¹ Synthetic research of this kind of compounds have been attracting the increasing interest of organic chemists. Because a total synthesis of polyol skeleton involved too many steps,² our synthetic efforts are focusing on search for a short and efficient approach and thus, we begin with readily available α-(-)-santonin(1). The creative key steps include generation of C₅-OH, the stereochemical reversion at C-7 and the cyclization of tetrahydrofuran. A successful approach is shown in the following scheme.

A Novel Cyclization of Squalene Initiated by Radical Cation

Wei Wang, Qing-Xiang Guo, Wei Yu, You-Cheng Liu

1998, 19(S1):  142-143. 

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Squalene 1 is recognized as the precursor of sterols and polycyclic triterpenoids that play important roles in numerous life processes¹. In view of the fact that the cyclization of hexa-1, 5-diene by γ-irradiation² and some isoprenoid polyenes by photochemical method³ through radical cation intermediates have been reported and that tris (p-bromophenyl)ammoniumyl hexachloroantimonate (TBPA⁺SbCl₆, 2) could oxidize olfines to the corresponding radical cations that underwent pericyclic reactions⁴, we thought it might be worthwhile to try the biomimetic cyclization of squalene initiated by radical cations. Previously we⁵ have reported the cyclization of geraniol and nerol to cis-p-mentha-2,8-dien-l-ol by reaction with 2. Herein, we report the cyclization of 1 initiated by 2 in dry dichloromethane to give 20-R-protosta-5,24-diene 3a and 20-S-protosta-5,24-diene 3b in the ratio of 1:1 with the total yield of 20%(Scheme 1).

Synthesis of 6-aryl-3-cinchophenyl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles

Peng-Fei XU, Lin-Mei ZHANG, Xin-Ping HUI, Zi-Yi ZHANG

1998, 19(S1):  144-145. 

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In recent years, fused heterocycles have been found to possess many unique properties in synthesis and pharmacology. Especially, 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles derivatives have been attracting much attention of chemists and pharmacologists because of their broad-spectrum biological activities such as antibacterial¹, hypotensive and CNS depressant² activities. We have prepared some 3,6-substituted 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles and found that these compounds exhibited antimacrobial, insecticidal and promote plant growth.^3-5 Cinchophen had been used widely as medicine in clinic,but has been obsolete in recent years due to its by-effect. In order to seek for other uses of cinchophen, as a continuation of our preceeding studies, we used cinchophen as the starting material to synthesize ten new 6-aryl-3-cinchophenyl-l,2,4-triazolo[3,4-b]-l,3,4-thiadiazoles 5a-j. Compound 1 was prepared by the reaction of cinchophen and ethanol in the presence of sulfuric acid. 1 then reacted with hydrazine hydrate in absolute ethanol to give 2 which yielded 3 on treatment with CS₂ and KOH. On refluxing of 3 with excess hydrazine hydrate, 4 was obtained. 4 reacted with various substituted benzoic acids in the presence of POCl₃ to afifort 5a-j.

Studies on Semisynthesis and Antibacterial Activities of 7β-(l-aryl-5-methyl-l,2,3-triazol-4-acylamido)-3-(2-substituted-1,3,4-oxadizol-5-thiomethyl) Cephalosporin

Xin-Ping HUI, Peng-Fei XU, Lan HAO, Zi-Yi ZHANG, Zuo-Wu GUAN

1998, 19(S1):  146-147. 

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Cephalosporin derivatives have been a subject in the field of β-lactam antibiotics due to their broad-spectrum biological activities in recent years. Chemical manipulation of the C-3 and 7β-position in the cephalosporin molecule has resulted in the discovery of numerous novel antibiotics. In general, the C-3 position of the cephalosporin were substituted with heterocyclyl sulfurs or nitrogens and the 7β-position were substituted with heterocycles or aryl¹. The side chain at 7β-position determined their antibacterial activities and antibacterial spectrum, moreover, the substituted groups at C-3 position not only affect pharmacokinetic properties, but antibacterial activities and antibacterial spectrum as well.² Roche Reiner company found that the activities of cephalosporin can be improved by changing the R of RCONH- at 7β-position of 7ACA and introducing various thioazoleheterocycles into C-3 position of it.³ It is no doubt that these heterocycles increased their activities and wided their antibacterial spectrum. In the course of our studies on the modification of cephalosporin, our efforts have been focused on introducing heterocycles into C-3 and 7β-position of 7ACA with the hope of achieving better antibiotics.

Synthesis of 6-(1-Aryl-5-methyl-1,2,3-triazol-4-yl)-3-(4-Pyridyl)-s-Triazolo[3,4-b]-l,3,4-Thiadiazoles

Xiao-Wen Sun, Yan Zhang, Zi-Yi Zhang

1998, 19(S1):  148-149. 

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A survey of literature¹ revealed that s-triazolo[3,4-b]-1,3,4-thiadiazole, an interesting fused system of s-triazole and 1,3,4-thiadiazole rings, has received much attention during recent years on account of its prominent utilizations as antifungal, antiinflammatory, antiviral, analgesic and anthelmintic agents probably resulting from its planner and compact structure. Our earlier work on the synthesis of this class of heterocycles showed antibacterial, herbicidal and plant growth regulative properties^2-3 for the compounds. 1,2,3-Triazole derivatives have found their wide use in medicine, agriculture and industry^4-5. Incorporation of 1,2,3-triazole moiety into the 6-position of this ring system may lead to achieving compounds of better biological activities. In view of the above findings coupled with scanty reports on these condensed compounds carrying 6-heterocyclic groups, we wish to report here the condensation of 4-amino-5-mercapto-3-(4-pyridyl)-l,2,4-triazole(2) with 1-aryl-4-carboxy-5-methyl-1,2,3-triazoles(1_a-j) as a part of our continuing interest in this area.

Regioselective Synthesis of Two Novel 2-geranyloxyacetophenones

Haifu GUO, Chusheng HUANG, Wenfei TAN, Yulin LI

1998, 19(S1):  150-151. 

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The phenols containing geranyl units¹ are a large group of interesting natural products exhibited many physiological actions as antiflammatory, antibacterial and antioxidative activities². Two novel acetophenones 1 and 2 were recently isolated from the fruits of Evodia merrillii, a small folk medicinal tree widely distributed in Taiwan³. Their structures were elucidated as 2-(1'-geranyl)-4,6-dihydroxyacetophenone 1 and 2-(1'-geranyloxy)-2,6,α-trihydroxyacetophenone 2 by means of spectroscopic data. So far as we know, the total synthesis of them have not been reported yet. Herein, we wish to report the first total synthesis of 1 and 2,starting from 2,4,6-trihydroxyacetophenone.

Total Synthesis of C-8-Geranylflavonoids

Chusheng HUANG, Zhe ZHANG, Yulin LI

1998, 19(S1):  152-153. 

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Geranylflavonoids are interesting natural products isolated in recent years from some traditional medicinal plants. Some of these flavanoids have been reported to exhibit hypotensive, antibacterial and antitumor effects¹. With respect to the synthesis of geranylflavonoids, only the 8-geranylflavanone skeleton as found in compounds 1², 2³ and 3⁴ has not been yet prepared.

The Total Synthesis of (±)-13-Hydroxyneocembrene

Yacheng Xing, Wen Cen, Ying Li, Jiong Lan, Yulin Li

1998, 19(S1):  154-155. 

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(13S)-hydroxyneocembrene(18), a cembranoid which was isolated in 1988 from soft coral Sarcophyton trocheliophorum¹, has been shown to be an effective inductor of the release of labeled glucose from the lecithincholesterol liposomes and have cytostatic activities². The geometrical structure and absolute configuration of 18 have been defined to be 1S, 2E, 7E, 11E, 13S. Herein, we report the total synthesis of (±)-13hydroxyneocembrene(18).

First Total Synthesis of the (±)-Preverecynarmin

Jiong Lan, Zuosheng Liu, Yulin Li, Wen Cen, Yacheng Xing

1998, 19(S1):  156-157. 

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The preverecynarmin(12), (+)-(1E,3E,7E,11E)-cembra-3,7,11-tetraen-6yl acetate,was first isolated in 1990 from both Armina maculata and its prey,the pennatulacean coral Veretillum cynomorium with other there briarane diferpenoids and cembene-C((1E,3E,7E,11E)-cembra-l,3,7,11-tetraen¹. As far as we known, the bioactive test and total synthesis of ¹² have not been reported yet. Herein we wish to describe the first total synthesis of (±)-preverecynarmin (12).

First Total Synthesis of 4,5-Secoeudesmane-type and Iphionane-type Compounds——Synthesis of 4,5-Dioxo-seco-γ-eudesmol and 5β,11-Dihydroxyiphionan-4-one

Zhaoming XIONG, Gang ZHOU, Xiaolei GAO, Yonggang CHEN, Yulin LI

1998, 19(S1):  158-159. 

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4,5-Secoeudesmane-type and iphionane-type compounds are sesquiterpenes with new carbon skeletons found in natrual sources in recent years.^1-6 The Co-occurence of 4,5-secoeudesmanes, iphionanes and eudesmanes as natrual products suggests that 4,5-secoeudesmanes, iphionanes most likely are generated biogenetically from eudesmanes, and iphionanes are formed biogenetically by aldol reaction of 4,5-dioxosecoeudesmanes.^1,4,6,7 The study on the synthesis of this two kind of new sesquiterpenes has not been reported in the literature.

Facile One-pot Transformation of 2,3-Epoxy Alcohols into Allylic Alcohols

Zuosheng LIU, Jiong LAN, Yulin LI

1998, 19(S1):  160-161. 

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Optically-active allylic alcohols have been frequently used as chiral building blocks for the preparation of optically pure compounds.¹ There are at present various methods for the synthesis of optically active allylic alcohols including the kinetic resolution racemic allylic alcohols,² reductive rearrangement of 2,3-epoxy alcohol by metal, halide and telluium-based chemistry.³ To our knowledge, One-pot Transformation of 2,3-epoxy alcohols into allylic alcohols, especially via epoxy iodides,is limited to Dorta's method³ using a Ph₃P,iodine, imidazole,2,6-lutidine and water system. The original Dorta's method can be successfully applied to the formation of tertiary allylic alcohols, but give unsatisfactory results in formation of secondary allylic alcohols.

First Total Synthesis of (-)-4-O-(6'-Hydroxy-7'(9')-Dehydro-6',7,-Dihydrogeranyl)-Coniferyl Alcohol

Zuo Sheng LIU, Chu Sheng HUANG, Jiong LAN, Yu Lin LI

1998, 19(S1):  162-163. 

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Some Ligularia species have long used as folk remedies due to their antibiotic, antiphlogistic and antitumor activities.¹ Compound 1,² a novel coniferyl alcohol, was isolated from ligularia duciformis(Compoitae). The geometrical structure of 1,determined by spectroscopic techniques, was corresponded to 4-o-(6,-hydroxy-7'(9')-dehydro-6',7'-dihydrogeranyl)-coniferyl alcohol. But its absolute configuration at C-₆,has not yet been determined. Herein, we report the total synthesis of (6'S)-(-)-1 from Geraniol 2 through 9 steps (Scheme 1).

First Total Synthesis of (±)-Ponganone Ⅲ

Wenfei Tan, Erqing Tang, Chusheng Huang, Yulin Li, Wen Cen, Yacheng Xing

1998, 19(S1):  164-165. 

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In recent years, the synthesis and pharmacology of pyranoflavanoids have been extensively investigated due to their wide range of pharmacological properties^[1-3]. Ponganone Ⅲ^[4],a new natural pyranoflavanone isolated from the Pongamia pinnala, was identified as (2S)-3',4'-dimethoxy-6',6"-dimethylpyrano-[2",3":7,8]-flavanone (2) on the basis of spectra data. Its precursor,3,4-dimethoxy-2'-hydroxy-6",6"-dimethylchromeno-[2",3":4',3']-chalcone (1) is also a new natural product^[5] isolated from the roots of Lonchocarpus subglaucescent. Their total synthesis have not been reported. Herein, we wish to report the first total synthesis of compounds 1 and 2 in order to confirm the proposed structure and further more to evaluate its biological activities.

Facile Synthesis of 6β-Hydroxy-7α(H)-eudesma-4-en-3-one and β-Cyperone

Gang ZHOU, Zhao Ming XIONG, Yong Gang CHEN, Yu Lin Ll

1998, 19(S1):  166-167. 

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Eudesmane derivatives have been drawing considerable attention due to their wide spectrum of biological proerties, particulaly antifeedant, cell growth inhibitory and plant growth regulating activities.¹ In recent years a number of C-6 oxyfunctionalized eudesmanes and β-dihydroagarofurans,such as compounds 3-6,have been isolated from nature sources. However the reports on the synthesis of this particular kind of compounds are few and the reported syntheses are generally by synthetic methodology starting from α-santonin 2². Our interest of study on the synthesis of this kind of compounds prompted us to investigate a new synthetic route from cheap material (+)-dihydrocarvone 7.

Total Synthesis and Stereochemistry of 13-Hydroxy-α-eudesmol

Yonggang Chen, Zhaoming Xiong, Gang Zhou, Lijun Liu, Yulin Li

1998, 19(S1):  168-169. 

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Recently, 13-hydroxy-α-eudesmol 1a was first isolated from C. uncata Cunn. by King and Robinson et aL and its structure was determined by high field NMR techniques, however, the absolute configuration of C-11 remained unsolved. Herein, we report the first total synthesis and determination of the stereochemistry of 13-hydroxy-α-eudesmol. In our synthesis (+)-α-selinene has also been accomplished.

Synthesis of a New Conformational Constrained Cyclic Peptide Containing Pyridine and Cystine

Hai Huang, Jinpei Cheng, Xiaohu Gao, Linjing Mu, Xubo Hu

1998, 19(S1):  174-175. 

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As a class of peptide series, cyclic peptides have aroused great interest in the past few years. They are found to possess many biological functions such as membrane transport, antibiotics, toxins, hormones and so on¹. Similar to the well-known macrocyclic compounds such as the crown ethers, cyclodextrins and calix arenes, they are found to be good host molecules as well in recognizing ions and small molecules². Recently, much progress has been made on the synthesis of conformational constrained cyclopeptides in this laboratory. Because introducing a rigid subunit to the backbone of cyclic peptides can largely reduce their, conformational complications and enhance their recognition affinities, Ranganathan³ and Cheng^4,5 and co-workers have synthesized some series of cyclic peptides analogues containing adamantane and benzene, respectively. These pseudocyclopeptides all showed good affinity to form complexes with ions and small molecules.

Design and Synthesis of Calix[4] arene-Constrained Cyclopeptide

Xubo Hu, Jin-Pei Cheng, Xinxin Han, Linjing Mu, Hai Huang, Jianming Lu

1998, 19(S1):  176-177. 

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There have been great continuing interests in cyclic peptides in the past two decades. Apart from being useful tools for identifying the functional conformations of bioactive peptides, and guiding the rational design of peptidomimetic drugs, cyclic peptides serve as templates in the de novo design^[1] of artificial proteins and as models^[2] for the study of prepefence in protein secondary structure. They also play an important role in ion transport across biological membranes,^[3] and can self-assemble size-adjustable nanotubes.^[4] However, study on their molecular recognitions for ions^[5] and neutral molecules, especially for organic compounds,^[6,7] which are believed to be one of the most attractive properties, were hampered by their considerable large degree of the freedom of the cavities.

Synthesis and Complexation of Phosphorus- and Selenium-Containing Macrocycles

Jinliang Li, Changqiu Zhao, Yongmei Wang, Jiben Meng

1998, 19(S1):  178-178. 

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A facile synthesis method for SePSe-containing macrocycles was developed. The macrocycles were obtained by one-pot reaction. The powder selenium was reduced by potassium borohydride in absolute alcohol to produce potassium diselenide,which reacted with bis(o-bromomethylphenyl)phenylphosphine oxide 1 to give the intermediate, 1-phenyl-2,3:8,9-dibenzo-5,6-diselena-1-phosphacyclononadiene 1-oxide 2, and its oligomer. Without isolation, the mixture was treated with potassium borohydride and sodium hydroxide to produce diselenide anion, then allowed to react with alkyl dibromide to give SePSe-containing macrocycles (shown as Scheme 1). A medium-sized eight-membered heterocycle, l-phenyl-2,3:7,8-dibenzo-5-selena-1-phosphacyclooctadiene 1-oxide 4 was obtained surprisingly. The formation of heterocycle 4 was due to the presence of potassium selenide when selenium was reduced by potassium borohydride. The attempts to isolate the intermediate 2 were totally unsuccessful. When the alkyl dibromide was the 1,2-dibromoethane, the expected macrocycle was not obtained, with deposition of red selenium and extrusion of ethylene. The similar case was reported by Pinto B. M. in 1989.

Studies on Synthesis and Biological Activities of Di-heterocyclic Compounds Containing Pyrazole

CHEN Hansong, LI Zhengming

1998, 19(S1):  182-183. 

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Pyrazole derivatives were reported to show a broad spectrum of biological activities. Some of these compounds exhibited fungicidal, herbicidal and insecticidal properties. For instance, Fipronil (MB46030) is a new pyrazole insecticide that provides excellent control of many soil and foliar insects on a wide variety of crops and noncrops^[1]. And ET-751 is a new 3-phenylpyrazole herbicide, its primary use is for the post-emergence control broad-leaved weeds in cereals^[2].These observations and our interest in looking for bio-active compounds prompted us to study pyrazole derivatives further.

A Preliminary Study of the Reaction of 5-Pyrazole Hydrazide and Malononitrile Derivatives

CHEN Hansong, LI Zhengming

1998, 19(S1):  184-185. 

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The reaction of alkyl hydrazine with ethoxymethylenemalononitrile (EMM) is a routine reaction, the corresponding product, pyrazole ring, will be obtained usually, For example, p-chlorophenylhydrazine with EMM^[1].However, 5-pyrazole hydrazide^[2] is different. When they reacted with EMM on condition that either reflux or room temperature, l,2-bis(5-pyrazolylcarbonyl)hydrazine (3),the abnormal products, instead of 5-amino-4-cyano-1-pyrazolylcarbonyl-¹H-pyrazole(⁴) were formed (see Scheme 1).

Synthesis of Novel Derivatives of 1,5-Dihydro-4,6-dithio-l,3,5,2-triazaphosphorine-2-oxide from N,N-bis(2-chloroethyl)diisocyanato phosphoramide

You Huang, Ruyu Chen

1998, 19(S1):  186-187. 

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Cancer is one of the most serious disease of human beings, and studies on antitumor drugs are still challenging scientists to look for new highly active compounds with low toxicity in this field. Cyclophosphamide (Endoxan), one of the most effective antitumor agents has been widely used in cancer chemotherapy¹. However, acrolein, from its metabolysis of hepatic mixed function oxidases in the liver, is toxic to the urinary system², hence,its clinical usage is restricted. With references to our previous works^3,4,we designed and synthesized a novel type of compounds Ⅰ with a nitrogen mustard group attached to the phosphorus atom of the heterocyclic ring in which the nitrogen atom at position 5 is from a α-substituted amino acid ester.

Synthesis of 1-(2'-Alkylthioethoxy)methyl Uracil and Thymine Derivatives

Xuejun Liu, Ruyu Chen

1998, 19(S1):  188-189. 

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There is a serious need for compounds that are effective in the treatment of cancer and virus (HIV. Human Immunodeficiency Virus,etc.). Among the large number of nucleoside analogs which have been synthesized and evaluated^(1-2) recently several 5'-alkylthio nucleosides have been reported to exhibit good antitumor and antiviral activities^(3-4). Their anticancer mechanism involves blocking cancer cell proliferation and inhibiting the cytoplasmic isozyme(C-TK)⁽⁵⁾, one isozyme of thymine kinase, which predominates in human tumor cell lines⁽⁶⁾. As we know, many acylic nucleoside analogs have appeared good biological activities⁽⁷⁾. It is reported that they can also act on some thymine kinases and end up the propagation of the viral DNA chain⁽⁸⁾.

Synthesis of Some 5'-Thiophosphononucleosides

CHI GUOCHEN, CHEN RUYU

1998, 19(S1):  190-191. 

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A series of 5'-diethoxythiophosphononucleosides involving diastereomers were synthesized, which as isomers of nucleotides were anticipated to possess potential biological activities.

SYNTHESIS OF SOME NEW TYPE CHRYSANTHEMIC ESTER

Liao Xiangjun, Zhang Chunxiang, Wang Likun, Dai Jianming, Liu Zhun

1998, 19(S1):  194-195. 

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Not only is Cantharidinum considered the active principle of antineoplastic drug in Chinese traditional medicine^[1], but also it and its natrii-cantharidas can be used herbicide and defoliant for legume plants. Seen from the structure of nor-cantharidinamine, it is a five-membered ring glutarimide,which is an active group in pesticide.

SYNTHESIS OF CYCLIC N-(2,4-DICHLOROPHENOXYACETYL)-O-DICARBOXIMIDES

Liao Xiangjun, Huang Guiqin, Zhang Chunxiang, Wang Likun, Liu Zhun

1998, 19(S1):  196-197. 

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Cantharidinum is not only considered the active principle of antineoplastic drug in Chinese traditional medicine^[1], but also it and its natrii-cantharidas can be used herbicide and defoliant for legume plants. Seen from the structure of nor-cantharidinamine, it is a five-membered ring glutarimide,which is an active group in pesticide.In 1986,Lacova,M. Reported that the cyclic N-(aryloxyacetyl)-O-dicarboximides exhibited herbicide and fungicide activity^[2],but as now there is no report that reports the synthesis and pesticide activity of the cyclic N-(2,4-dichlorophenoxyacetyl)-O-dicarboximides^[2].So we base on the derivative of nor-dehydrocantharidin and 2,4-dichlorophenoxyactic acid to make 6 compounds be synthesized,which were characterized elemental analysis, HNMR,MS.Pesticide activities of these compounds are being tested.

Combinatorial Synthesis of O-Pyrimidinyl Substituted Methyl-α-D-Glucopyranosides

Yun Liao, Zheng-Ming Li, Henry N. C. Wong

1998, 19(S1):  198-199. 

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Within last decade, many pyrimidinyl oxy substituted alcohols, aldehydes and carboxylic derivatives had been found with prominent bio-activities such as high herbicidal activities with wide spectrum. After extensively study of the relationship between structures and bioactivities, A brand-new scaffold combining both pyrimidinyl and glucoside moieties was designed and other building blocks were further introduced with the help of polymer-supported regioselective protecting groups. As shown below, a combinatorial synthesis was carried out by applying "mix-split" method to produce the following series of small compounds libraries both in solid-phase and liquid phase.

Design,Synthesis and Activities of Cyanouracils Photosystem Ⅱ Inhibitors Basen on D1 Protein

Huayin Liu, Huifen Tan, Huazheng Yang

1998, 19(S1):  200-201. 

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The study on the interaction between protein target and little molecules can help design new drugs, which have more selective and higher activities. A large number of inhibitors,including ureas, triazines and phenols etc.,are known to block photosystem Ⅱ by displacing plastoquinone from the Q_B-binding niche of the D1 protein in the reaction center. The X-ray crystall structure of D1 protein in high plant is unknown, but the X-ray crystal structure of L protein of photosynthetic reaction centre of Rps. Viridis has already proved in 80'. Based on this structure, the 3D-structure of Pisnm Saihmm 32Kdal (Dl) was constructed by homology modeling method, and the properties, such as steric, hydrophobic, electrostatic properties of active sites region of the Dl protein were also characterized by Grid Search method with probes of CH₃E, H₂O, NT and proton.The detail proposal of the model will be shown elsewhere.

Design, Synthesis and Activities of Cyanoacrylates Photosystem Ⅱ Inhibitors Basen on D1 Protein

Huayin Liu, Huifen Tan, Huazheng Yang

1998, 19(S1):  202-203. 

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Photosynthesis is a particularly attractive target for the design of potential commercial herbicides. Since photosynthesis is a mechanism that occurs in plants only, all inhibitors are in theory nontoxic to mammals. A large number of inhibitors, including ureas, triazines and phenols etc., are known to block photosystem Ⅱ by displacing plastoquinone from the Q_B-binding niche of the D1 protein in the reaction center. The X-ray study by Deisenhofer et al. of the photosystem of Rps viridis was an important milestone, since it initiated molecular modeling studies in academia and instustry in order to find new PS Ⅱ inhibitors.

The Chlorination of O-Alkyl S-Alkyl(aryl) Thiophosphoric(-nic) Acid Derivatives with Phosphorus Oxychloride——A New Convenient Method for Synthesis of Chiral S-Alkyl(aryl) Thiophosphoro(-no) Chloridates

Chu-Chi Tang, Zheng-Jie He, Wen-Bing Chen, Fu-Peng Ma, Zheng-Hong Zhou

1998, 19(S1):  206-207. 

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In our laboratory, the isomerization/chlorination of a variety of O,O-dialkyl phosphoro(-no)thionates 1 with phosphorus oxychloride have been systematically studied. It was found that when R' equals aryloxy^[1], alkylthio^[2], arylthio^[2], dialkylamino^[3], phenyl^[4], methyl^[5],and nitrogen heterocyclic group^[6] in 1,respectively, this reaction can proceed smoothly and gives the desired products ² and ³. Hence, it provides a general synthitic method for S-alkyl thiophosphoro(-no)chloridates, especially for the asymmetric ones.

A Novel Tandem Reaction for the Synthesis of Fused Pyrazoles

Zhongwen Wang, Zhengming Li

1998, 19(S1):  208-209. 

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Some of the fused heterocyclic compounds are important pharmaceuticals and agrochemicals. Study on their synthetic methodology is also very important in heterocyclic chemistry. The synthesises of 1H-pyrazole[5,1-b]thiazole^[1-2] and lH-thieno[2,3-c]pyrazole^[3-5] were reported by fewer literatures.

Regioselective Addition of 5-Amino-l,2,4-Triazoles and Its Analogues with Arylsulfonyl Isocyanates

Guang-Fu YANG, Hua-Zheng YANG

1998, 19(S1):  210-211. 

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5-Amino-3-benzyl (aryl)thio-1,2,4-triazoles and its analogues (pyrazole) 1 are important intermediates for the syntheses of a lot of biological active compounds^[1,2]. In our previous paper^[3], we reported the regioselective addition of 1 with aryl isocyanates and the experimental results showed that the orientation of the addition of 5-amino-3-benzyl (aryl)thio-1,2,4-triazoles and its analogues with the aryl isocyanates can be directed by controlling the reaction temperature.The 1-position adduct 2 was obtained regiospecifically below 120℃, whereas the 5-position adduct 3 was obtained selectively when the reaction temperature was raised to 170℃ (Scheme 1).

Synthesis of Ethyl 2-Cyano-3-Methylthio-3'-Arylaminoacrylate From Low Nucleophilic Amine

Huazheng Yang, Huayin Liu, Kai Chen

1998, 19(S1):  212-213. 

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The synthesis of ketene N,S-acetals has attracted a considerable attention as building blocks in organic synthesis, especially in the preparation of heterocycles^[1]. The addition reaction of ketene S,S-acetals with highly nucleophilic amines, such as alkylamines, can easily afford the corresponding ketene N,S-acetals, under gentle condition, which could be converted into conjugated ketene aminals by reaction with a second equivalent of the same or a different amine^[2,3]. However, this addition reaction with low nucleophilic amines, such as arylamine or heterocyclic amine, can hardly give the corresponding ketene N,S-acetals under gentle conditions. If under powerful condition,such as refluxing, the addition reaction affords a mixture of the N,S-acetals and conjugated ketene aminals^[4]. Recent studies showed that this addition reaction with low nucleophilic amines affords the corresponding ketene N,S-acetals in the presence of a catalyst^[5].

“Approximation”-Novel Methodology to Identify the Active Components from Compounds Library

YU Ai-Ming, TAN Hui-Fen, YANG Hua-Zheng, ZHANG Zheng-Pu

1998, 19(S1):  216-217. 

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Combinatorial chemistry has been regarded as one of the most efficient method in medicinal chemistry. Identification of active compounds from compounds library is one of the main steps of combinatorial chemistry. Many approaches have been developed for this purpose, such as deconvolution^[1] positional scanning^[2], SURF^[3],orthogonal library^[4], indexed library^[5], core molecule library^[6] etc. Actually, all the methods are based on the rule of determining the structure of "Active Components" or "Active Compounds"(AC) from "Active Compounds Library"(ACL) by identifying "Active Building Blocks"(ABB). In this way, more efficient method named "Approximation" was developed by reducing the ABB by half in every steps, which was depicted as below by taking "8ҿ8" library as a example.

The Synthesis of Novel ALS Inhibitors N-(Substituted Phenyl Alkoxy Phosphonyl)-N'-(4,6-Disubstituted Pyrimidin-2-yl) Ureas

Guo-Feng ZHAO, Yong-Hong LI, Hua-Zheng YANG

1998, 19(S1):  218-219. 

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Sulfonylurea herbicides are a new class of herbicides discovered in the mid-1970's^[1],whose mode of action has been established as the inhibition of ALS^[2]. Much attention has been focused on this kind of compound, since they have unprecedented use rates, a high degree of selectivity, and excellent environmental safety. Numerous modifications of the structure of this class of herbicides have been reported.

The Synthesis of Novel ALS Inhibitors N-(Substituted Benzyl Alkoxyl Phosphonyl)-N'-(4,6-Disubstituted Pyrimidin-2-yl) Ureas

GuO-Feng Zhao, Xiao-Mao ZOU, Yong-Hong Li, Hua-Zheng Yang

1998, 19(S1):  220-221. 

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Sulfonylurea herbicides are a new class of herbicides discovered in the mid-1970's^[1],whose mode of action has been established as the inhibition of ALS (acetolactate synthase)^[2]. Much attention has been focused on this kind of compound, since they have unprecedented use rates,a high degree of selectivity, and excellent environmental safety. Numerous modifications of the structure of this class of herbicides have been reported.

The Synthesis and Bioactivity of New Thiosemicarbazides and Thiadiazole Derivatives Including Substituted Pyrazolyl group

Guo-Feng ZHAO, Lin ZHANG, Yu FU, Gui-Yu JIN

1998, 19(S1):  222-223. 

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Thiosemicarbazide derivatives have excellent biological activities, for example, insecticidal, plant-growth regulating activity, which can be cyclized to give heterocyclic compounds having potent activity. The bioactivities of thiosemicarbazide derivatives are directly related to the substutients on 1- and 4-position.

Studies on Bioactive Selenium-containing Organophosphorus Compounds: Synthesis of 1-Aminoalkanephosphonate Derivatives of Benzisoselenazolone and Their Antitumor Activity

Jia Zhou, Ru-Yu Chen

1998, 19(S1):  224-225. 

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Various selenium-containing compounds are widely used as reagents and intermediates in organic synthesis.¹ In recent years biologically active organoselenium compounds have begun to attract considerable interest due to their unique and diverse potential pharmacological importance such as broad spectrum antitumor and antiviral activities, and some of them are even many times more active than their thio analogues.^2,3 It was found that benzisoselenazolones[e.g.,Ebselen, 2-phenyl-1,2-benzisoselenazol-3(2H)-one], are effective for the treatment of diseases caused by cell damage owing to increased formation of active oxygen metabolites⁴ and these pharmacological effects are mainly attributed to the glutathione peroxidase (GSH-Px) like properties.⁵

Synthesis of Phosphonodipeptide Derivatives of Exo-(7-oxa)bicyclo[2.2.1]heptane(or exo-Bicyclo[2.2.1]hept-5-ene)-2,3-dicarboxylic Anhydride

ZHOU Zheng-Hong, CHEN Ru-Yu

1998, 19(S1):  226-227. 

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Cantharidin, exo-4a,7a-dimethyl-4,7-epoxyhexahydroisobenzofuran-l,3-dione (1),has displayed significant antitumer activities in vitro and in vivo. The adverse effects on urinary and gastrointestinal tracts prevent it to be accepted by the clinic. The structural modification of cantharidin was suggested by us with the aim to decrease its toxicity and maintain or increase its activity. Organophosphorous-containing molecules of pharmaceutical use, such as the α-aminophosphonic acid dipeptide, alaphosphin (2), which inhibits alanine racemase^[2],are becoming increasingly important. We therefore designed and synthesized a series of phosphonodipeptide derivatives with α-aminoalkylphosphonate in N-terminal of exo-(7-oxa)bicyclo[2.2.1]heptane(or exo-bicyclo[2.2.l]hept-5-ene)-2,3-dicarboxylic anhydride, which might be interesting to people researching in the areas of chemistry, biochemistry and pharmacology.

Synthesis of 1,2-Cyclic Monoacyl-rac-Glycerothio-phosphates of Cantharidin Analogs

ZHOU Zheng-Hong, CHEN Ru-Yu

1998, 19(S1):  228-229. 

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Mylabris, the dried body of the Chinese blister beetle, has been used as Chinese medicine for over 2000 years. Its active constituent, cantharidin, has anti tumor activities and causes leukocytosis. The synthesis of cyclic glycerophospholipid containing cantharidin analogs has so far not been reported in literature. The conjugates of this type are not only new prodrugs of cantharidin antitumor agents but also may generate two cytotoxic groups against different target sites inside a neoplastic cell. Such types of compounds may be of interest in chemistry, biochemistry and pharmacology. This paper deals with the synthesis of 1,2-cyclic monoacyl-rac-glycerothiophosphates of cantharidin analogs as new models of phospholipids.

A New Method for the Synthesis of Oligo-peptides

Hegui Gong, Zhaolong Li, Hua Fu, Yufen Zhao

1998, 19(S1):  232-233. 

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It was discovered that polypeptides were formed by self-assembly of N,O-bis(trimethylsilyl)amino acids with the assistance of O-phenylene phosphorochloridate.^[1] There were three steps involved in the self organization reactions, the activation of amino acid, the elongation of peptide chain and the termination of the chain reaction,among which the activation of amino acid -the formation of imino (alkyl)acetoxyphosphoranes was the key step. The formation process of the penta-coordinated phosphorus intermediates was showed in scheme 1.^[2,3,4] Through further studies of the mechanism of self-assembly reaction, it was found that carbonyl groups of the intermediates attacked by the neuclophilic groups were direct reson of the formation of peptides. However, the peptides in the solution were very difficult to be separated and analyzed.

Synthesis of Phosphopeptides with Enzymatic Protecting Group

Yan-Mei LI, Yu-Fen Zhao, Herbert Waldmann

1998, 19(S1):  234-235. 

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Reversible protein phosphorylation is widely recognized as an important mechanism for the regulation of many cellular processe^[1]. For the study of the roles of the phosphoproteins in biological processes, structurally well-defined compounds are often needed, which contain the characteristic structural units of the parent biomacromolecules, i.e. the linkage regions between the peptide chain and phosphoric acid esters.

Synthesis of N^α, N^ε-Bis(O-deoxythymin-3'-ylO-isopropyl phosphoryl) Lysine Methyl Ester

Bo Han, Yu Chen, Yu-Fen Zhao

1998, 19(S1):  236-237. 

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The report of Lienhard and Secemski¹ on the potent inhibition of adenylate kinase by the dinucleoside analogue of adenosine, P1, P5-di(adenosine-5')pentaphosphate (Ap5A), stimulated our synthesis of N^α, N^ε-bis(O-deoxythymin-3'yl O-isopropyl phosphoryl) lysine methyl ester (BTPL) as a potential inhibitor of the metabolic pathway concerned with the biosynthesis of DNA-thymine. To our knowledge, it's the first example of lysine linked two nucleotides through P-N bond.

SYNTHESIS OF PORPHYRIN NITROGEN MUSTARDS AND THEIR ANTI-TUMOR ACTIVITIES

Zhi-Long Chen, Jin-Rong Chen, Wei-Qin Wan, De-Yu Xu

1998, 19(S1):  240-241. 

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With the development of laser medicine and technology in light-conducted fiber and endoscope, photodynamic therapy (PDT) obtained regulatory approvals in the United States and elsewhere to cure malignent tumors in skin, esophagi, bronchi and bladder for it's selective tumoricidal effects without the serious side effects of conventional therapy in a variety of tumors. We focused our attention on both the alleviation of patient's suffering from damages of normal tissues in chemotherapy and the eliminating of cutaneous photosensitivity as well as the enhancement of the depth of tumor necrosis which is generally not more than 8-10 nm even under the maximum safe light dose in PDT. Thus, a series of new compounds porphyrin nitrogen mustards, namely, 2,7,12,18-tetramethyl-13,17,di[3-N,N-di(2-chloroethyl) amino propyl] porphin (I₁) and 2,7,12,18-tetramethyl-3,8-di(l-alkyloxyethyl)-13,17-bis[3-N, N-di(2-chloroethyl)amino propyl]porphin (I_2-8) were synthesized(I) by introducing the alkylating agent nitrogen mustard into the periphery of porphyrin(Scheme 1). The mean overall yield of I_2-8 is 13%.

SYNTHESIS OF MESO-TETRA(SUBSTITUTED PHENYL) PORPHIN NITROGEN MUSTARDS WITH POYENTIAL ANTI-TUMOR ACTIVITIES

Zhi-Long Chen, Jin-Rong Chen, Wei-Qin Wan, De-Yu Xu

1998, 19(S1):  242-243. 

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With the development of laser medicine and technology in light-conducted fiber and endoscope, photodynamic therapy (PDT) obtained regulatory approvals in the United States and elsewhere to cure malignent tumors in skin,esophagi, bronchi and bladder. PDT is based on the ability of some porphyrins and porphyrin-like chromophores to be accumulated selectivity in tumor tissues; tumor necrosis can be obtained by irradiation of the neoplastic area with light of the appropriate wavelength. Until now a few thousand patients have been successfully treated by PDT worldwide. Hematoporphyrin derivatives (HpD) is a complex mixture of porphins which could retain in skin and the cutaneous photosensitivity lasting for 6 to 8 weeks after the treatment was resulted in.To alleviate patient's suffering from damages of normal tissues in chemotherapy and eliminate cutaneous photosensitivity as well as enhance the depth of tumor necrosis, we synthesized a series of new compounds by introducing the antitumor group nitrogen mustard into the periphery of meso-tetraphenyl porphins.

The synthesis of fungicidal 4-(1-methyl-3-trifluoromethyl)pyazolylcarbonyl hydrazines

Li Bin, Man Ying, Li Zhi-Nian

1998, 19(S1):  244-244. 

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Many heterocyclic amides possess good fungicidal activity. It is found that the 4-(l-methyl-3-trifluoromethyl)pyazolyl amides Ⅰ controlled a number of crop diseases⁽¹⁾. But little 4-(1-methyl-3-trifluoromethyl)pyazolylcarbonyl hydrazines are investigated in the literature.

The synthesis of herbicidal 4-pyrimidinyl sulfonylureas

Li Bin, Man Ying, Guo Gui-Wen

1998, 19(S1):  245-245. 

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A number of 2-pyrimidinyl sulfonylureas are commercialized ALS-inhibiting herbicides to control broad-spectrum weeds in various crops when applied at very low dosage (5-50g/ha)⁽¹⁾.But little 4-pyrimidinyl sulfonylureas are investigated in the literature.

The synthesis of herbicidal methyl 2,6-bis(4,6-dimethoxy-2-pyrimidinyIoxy) benzoate

Li Bin Man Ying, Zhang Zong-Jian

1998, 19(S1):  246-246. 

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The pyrimidinyl carboxys as ALS-inhibiting herbicides were discovered in 1987 to control broad-spectrum weeds especially to barnyard grass in rice and cotton when applied at very low dosage (10-150g/ha)⁽¹⁾⁽²⁾. Three this kind of compounds are commercialized recently. The synthesis of methyl 2,6-bis(4,6-dimethoxy-2-pyrimidinyloxy) benzoate is not reported in the literature.

The synthesis of herbicidal 2-phenylthio-pyrimidinones

Li Bin, Man Ying, Guo Gui-Wen

1998, 19(S1):  247-247. 

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Many pyrimidinones possess good broad-spectrum herbicidal activity at 500g/ha⁽¹⁾. The 2-phenylamino-pyrimidinone I kills barnyard completely at 250g/ha pre-emergencet⁽²⁾. But little 2-phenylthio-pyrimidinones are investigated in the literature.

Synthesis of Some Novel 3-Pyrazolyl-1,2,4-oxadiazoles

Liu Changling, Lei Xin, Zhang Lixin, Li Bin

1998, 19(S1):  248-248. 

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Compound Ⅰ was discovered in our synthesis program, which has good insecticidal and acaricidal activities, but not good enough compared with fenpyroximate^[1]. In order to discover new and more active compounds, Compound Ⅰ was used as lead and the following compounds Ⅱ were designed and synthesized. Their structures were confirmed by IR, ¹HNMR and MS. Their screenings are under progress.

Synthesis of Some Novel Pyrazolecarbaldehydeoxime Derivatives(Ⅲ)

Liu Changling, Lei Xin, Zhang Lixin, Li Bin

1998, 19(S1):  249-249. 

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Pyrazolecarbaldehyde oximes compound,fenpyroximate, is very good acaricide, and compound (Ⅰ) was discovered in our synthesis program, which has good insecticidal and acaricidal activity, but not good enough compared with fenpyroximate. In order to discover new and more active compounds used as pesticide,compound (Ⅰ) was used as lead and the following compounds (Ⅱ) were designed and synthesized. Their structures were confirmed by IR, ¹HNMR and MS. Their screenings are under progress.

Synthesis of Some Novel Methoxyacrylates and Their Biological Activities

Liu Changling, Liu Xiaonan, Lei Xin, Zhang Lixin, Li Bin, Steve H Shaber, Richard M Jacobson

1998, 19(S1):  250-250. 

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Methoxyacrylate fungicides which came from natural product have an excellent,broad spectrum of activities, highly safety and selective to target because of their unique mode of action-inhibit mitochonidrial respiration by blocking electron transfer between cytochrome b and cytochrome c₁, so more attention was paid by many companies in agrochemicals and at least 300 patents was applied until now. For the action of blocking electron transfer,some one suggests this kind of chemicals should not only work on fungi,but also on insects (sure) and weeds. Up to now,no herbicidal activity was reported. So the following compounds Ⅰ (X=O,NR,in patent:X=O,S rarely X=N) were designed and synthesized by introduced some fragment of herbicide.

Synthesis of Some Novel Oxime Derivatives and Fungicidal Activity

Liu Changling, Lei Xin, Li Zhinian, Li Bin, Zhang Lixin

1998, 19(S1):  251-251. 

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Some compounds containing oxime type such as fenpyroximate have good activity used as pesticide. In order to discover new lead, the novel compound (Ⅰ-Ⅴ) were designed and synthesized. Their structures were confirmed by IR, ¹HNMR and MS.

Synthesis of Some Novel Pyrazolecarbaldehydehydrazones Derivatives

Liu Changling, Liu Xiaonan, Lei Xin, Li Bin, Zhang Lixin

1998, 19(S1):  252-252. 

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The compounds of general structure(Ⅰ) have good insectidal activities, which were published recently(JP06-247969,JP07-101930A, JP07-138233A, JP07-165697A, etc.). In order to discover new lead, the following compounds (Ⅱ), novel pyrazolecarbaldehydehydrazone derivatives, were designed and synthesized by introducing the active group pyrazole into the structure(Ⅰ) instead of the benzene ring. Their screenings are under progress.

Enantiospecitic Synthesis of 1N-Sulfa-3-Nitro-4-(l,2-Acetonide)-2-Azetidmones

Henguang Li, Rugang Xie, Tong Wua, Jian Hu, Yiemin Lei

1998, 19(S1):  253-254. 

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β-lactams are not only to be excellent antibiotics used widely in clinic treatment of many bacteria infected disease but also express some other potential physiology activities, such as antifungal, enzyme inhibition, antineoplastic agent,hypocholesterolemic agent¹⁾. In fact,there are much more methods in the synthesis of derivatives β-lactam²⁾. In the course of our synthetic studies towards a series novel β-lactam analogs we have required a variety of higher optic purity key intermediates. Hear we would like to report the quite easy and versatile way by the cycloaddition of chiral alkene and chlorosulfonyl isocyanate (CSI) to produce those importent mono-ring compounds³⁾.

Spiral Cyclization of a-Carbonyl Radicals

Chin-Kang Sha, Wen-Yueh Ho, Ching Hung Lin, Shih-Min Lin

1998, 19(S1):  255-255. 

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α-Carbonyl radicals cyclization reactions have been applied successfully toward total synthesis of several natural products,such as modhephene,¹ (-)-dendrobine,² and (-)-5-oxosiphiperfol-6-ene.³

Anionic Cyclization Approach to Hexahydrobenzo[b] furan-3-one and Hexahydro-1H-3-indolone:Application to Total Syntheses of Natural Products

Chin-Kang Sha, Shih-Jung Huang, Jainn-Ming Huang, Danialdoss S., An-Wei Hong

1998, 19(S1):  256-256. 

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Hexahydrobenzo[b]furan-3-one(3) and hexahydro-1H-3-indolone (4) are potentially useful intermediates for total synthesis of natural products, such as the hexahydrobenzofuran unit (5) of avermectins and pancracine (6). Anionic cyclization approach toward (3) and (4) have been developed. Their application to the total synthesis of (5) and (6) will be presented.

Synthesis of p-Aminophenyl Heteroaromatic Pyrroles

Chin-Kang Sha, Liang-Jyi Chen

1998, 19(S1):  257-257. 

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Three general methods for synthesis of heteroaromatic pyrroles were reported recently from our laboratory.¹ Application of these methods to the preparation of p-aminophenyl heteroaromtic pyrroles 3 will be discussed. Potential use of p-aminophenyl substituted heteroaromatic pyrroles 3 as electroluminescent materials is under current investigation.

双分子络合维生素B₁₂模型化合物的合成

1998, 19(S1):  258-259. 

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B₁₂是人体中不可缺少的维生素^[1,2],近20年来对这类化合物的研究引起人们广泛的兴趣^[3-5]。为研究维生素B₁₂结构与性能的关系,我们以维生素VB₁₂为原料合成了VB₁₂模型分子4f^[6,7],以研究Co-N键的强弱。揭示在人体中的生物催化作用。在我们合成工作中意外地发现了VB₁₂模型分子具有双分子络合现象,在一定条件下合成了VB₁₂分子络合物5b-5f。为研究B₁₂化学提供了一类新型模型分子。

A New Procedure for Preparing 7-Nitro-l,3-benzodioxane and Its Application in the Synthesis of Phosphonates

Li Chunbao, Wang Yonghuei, Wang Tianyu, Li Nan, Yu Zhifang

1998, 19(S1):  260-260. 

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The reproducible yield of 7-nitro-1,3-benzodioxane (2) from the reaction of 3-nitrophenol and 40% formaldehyde catalyzed by sulfuric acid is less than 1%[1]. By replacing formaldehyde with triformol, followed by treatment of the crude product with 10% NaOH solution, we have improved the yield to 12%. An orthogonal design experiment was carried out to optimize the conditions[2].

Synthesis of N,N-Bis(4-pyridinyl)piperazine (Bis-DMAP) as Novel Supernucleophilic Reagent

Huang Ji-Tao, Zhang Jia-Qi, Zheng Si-Hua, He Jia-Qi

1998, 19(S1):  261-262. 

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In the late 1960's,4-(N,N-dimethylamino)pyridine (1,DMAP) and 4-pyrrolidinopyridine (2, PPY) as high efficient supernucleophilic catlyst the benzoylation of m-chloroaniline were found independently by two research groups.^[1,2]

A Study of Surfactants'Role in the Synthetic System of Anthraquinone-Series Colors

Sun Jiyou, Cao Aili, Zheng Yazi, Xue Bing, Zhang Jiaqi

1998, 19(S1):  263-264. 

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Solubility of dyes has been paid attention to since successive dyeing and printing operation of dyes widely applied in textile industry is carried out. However, solubility improvement of the studied dyes has seldom been reported with consideration of added relevant surfactants in the synthetic system of the dyes.

The Reaction of Japanese Reagent with Aminoacetamide with Alkyl Group

Liang Nian HE, Ren-Xi ZHUO, Ai-Hong Luo, Fei CAI, Kai LI

1998, 19(S1):  269-270. 

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2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide¹,commonly known as Lawesson's reagent (LR,1a),and Japanese Reagent (1b),are not only thiating agent for diverse carbonyl compounds^1-3, but also they undergoes ring-closure reactions with contain substrates containing two functional groups to give phosphorus heterocycles which contain phosphonothioyliene {C₆H₄-P(S)〈} moiety. These heterocyclic compounds are of potential interest as herbicides,insecticides,and fungicides^4,5. Glycinamides are known as biologically active materials, for example, herbicides, plant-growth regulator⁶. In order to look for potent herbicides⁷ and to extent the use of Japanese Reagent to other bifunctional substrates,its reactions with 3-alkyl-glycinamides 2 have been investigated and found to give new phosphorus heterocycles which possess Significant selective herbicidal activity against rape. Here are our results.

Study on the Reaction of Tricovalent Chlorophosphines with Aldehydes Containing Withdrawing Electron Groups

Liang Nian HE, Ren Xi ZHUO

1998, 19(S1):  271-272. 

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α-Polychloroalkyl phosphoric dichlorides and their derivatives 2,3,4 has insecticidal activity^1-4 and may be used as an intermediate to make other insecticides by reaction with alcohol, phenol, thiophenol or mercaptan. They can be prepared by various conventional methods of preparing phosphorus thioesters. Here we wish to report the addition reaction of tricovalent chlorophosphines with aldehydes containing withdrawing electron groups and its application in preparing of polychloroalkyl phosphorus dichlorides and their derivatives. The process can be represented by the following equation.

Trimethylaluminium Mediated Rearrangement-addition Reaction of Trisubstituted Gibberellin Epoxides

Anqi Chen, Christine L. Willisb

1998, 19(S1):  273-274. 

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The gibberellins (GAs) are a group of naturally-occurring tetracyclic diterpenoid plant growth hormones which are essential to the normal growth and development of plants. Over one hundred different GAs have been identified to date and most of these compounds are present in Nature only in minute quantities. Among the biosynthetic pathways of the gibberellins, the oxidation and subsequent removal of carbon-20 in C₂₀-GAS (e.g. 1 and 2) to form C₁₉-GAs (e.g. 3 and 4) is one of the most important process in which GA 20-oxidases are involved¹ (Scheme 1). During the course of our investigation into this process, we needed to have access to C₂₀-GAS such as (2) from a more abundant C₁₉-GA such as GA₃ (5). A successful route for such transformation may then be adapted for the synthesis of isotopically-labelled C₂₀-GAS for biological studies.

Migration of Double Bond of Alkene in the Reaction of Iron-Catalyzed Olefination from Sulfonylcarbanion

Jin Li-ren

1998, 19(S1):  275-276. 

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Sulfonylcarbanion can be converted into alkene by elimination⁽¹⁾(eq 1),mix-coupling⁽²⁾ (eq 2) or homocoupling⁽³⁾ (eq 3) under iron catalysis. Besides desired alkenes, isomerized alkenes were detected in the reaction of elimination or mix-coupling. However, no migration of double bond in alkene was found in homocoupling reaction. Some experimental results were obtained to discuss the alkene isomerism in the iron-catalyzed sulfonylcarbanion olefination and some evidences were given to support the proposed mechanism of iron-catalyzed sulfonylcarbanion olefination.

Studies on the Bicyclolphosphite of Saccharides

Cao Linghua, Sun Guanzhong, Liu Yuting

1998, 19(S1):  281-282. 

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Bicyclophosphitication of saccharide was used for synthesis of optically active organic phosphor compounds widely. The sugars contained phosphite ring are the inductor in stereochemistry. The nucleophilic subsitution on tetrahedron-phosphor atom is provided with specific stereo-direction. These compounds, with highly stereoselectivity, and can be used as the highly selectivity reagent for organic reactions.

A NEW METHOD OF SYNTHESIS β-D-MANNOPYRANOSIDE BY STEREOCONTROLLED PROCEDURE

Jian-Xin YU, Fang-Min LIU, Jin-Xiu SU, Wen-Jie LU, Yan-Ping LI, Yu-Ting LIU, Xu-Li TANG, Ying DONG, Meng-Shen CAI

1998, 19(S1):  283-284. 

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The β-D-mannopyranoside bond is an important structural element of N-glycoproteins, widespread in multicellular organisms as serum, cytosol, and membrane compounds^[1]. However, as both the neighboring group assistance and steric repulsion as well as the anomeric effect uniformly favor the formation of α-D-mannopyranoside, the β-D-mannopyranosyl linkage still remains especially difficult to be constructed.

Synthesis of Heterocyclic Compounds from 2-Phenyl-l,2,3-Triazole-4-Formylhydrize

LIU Fang-ming, YU Jian-xin, LU Wen-jie, LIU Gang, LIU Yu-ting, Xu-Li TANG, CHEN Yao-zu

1998, 19(S1):  285-286. 

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Many compounds containing the 1,3,4-oxadiazole and/or1,2,3(or 4)-triazole and thiadiazole ring system are reported to possess antibacterial^[1], antiinflammatory^[2], anticonrulsant^[3],CNS stimulant^[4] and pesticidal^[5] activities and excellent anthelmintic properties^[6,7]. In view of this and the results of the combined different nuclei system in a molecular always enhancing the therapeutic activities,the present work deals with the synthesis of the combined different pharmacologically active nuclei system mentioned above in a molecular through some new method.

Asymmetric Diels-AIder Reactions of (E)-1-Phenylsufonyl-3-alken-2-ones with Open Ring Diene Catalyzed by a Chiral Titanium Catalyst

PEI WEN

1998, 19(S1):  289-290. 

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We have reported the reactions of (E)-1-phenylsufonyl-3-alken-2-ones 1, as useful chelating dienophile, with cyclopentadiene catalyzed by a chiral titanium catalyst. The Diels-Alder adduct was prepared in 90% yield and 100% enantioselectivity¹. Our continuing interest has been focused on utilization of the sulfonyl-functionalized bidentate chelating enone 1 as prochiral substrate in catalytic asymmetric reaction. This led us further investigate the expanding utilization of the substrate 1 in the asymmetric Diels-AIder reaction. Here the reaction of (E)-l-phealy-sufonyl-3-alken-2-ones 1 with open ring dienes was proceeded by the use of the chiral titanium catalyst.

Synthesis, Characterization and Xerographic Performance of the Triazo Pigments from Tris(4-amino)triphenylamine

Jinhong Pan, Zhongping Huang, Yuhong Zhang, Qingsen Yu, Guoqiang Cai

1998, 19(S1):  291-292. 

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As the era for digital printer has come since the 1990s,the investigation into a highly photosensitive charge generator materials(CGM) suitable for IR photoreceptor is concerned.^1-2 This research focuses on the triphenylamine triazo pigments, which exhibit a broad spectral response(450-800mn) and an excellent photosensitivity, especially in the near red-infrared region where solid-state diode laser emit(450-800nm). They are particularly potential CGM for laser printer and digital printer.

Studies On The Molecular Design and Synthesis OF N1-Substituted Fluoroquinolones

Wang Guoping, Zhu Longguan, Yu Qingsen

1998, 19(S1):  293-294. 

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Fifteen N1-Substituted fluoroquinolones were optimized by MMPMI. Employing the indexes of molecular connectivity and quantum chemistry. Four equations of QSAR were obtained through stepwise regress. According to the QSAR equations, the antibacterial activities were predicted for four N1-Subsituted fluoroquinolones, which were unreported till now. The four compounds were synthesized and characterized by IR, UV,¹H-NMR and elementary analysis. The determined results show good antibacterial activixinties against G^- and G⁺.

CONDENSATION REACTION OF α-AROYL-α-ACETYL KETENE CYCLIC DITHIOACETALS WITH AROMATIC ALDEHYDES

XIE Zhongwei, ZHANG Shujia, CHEN yaozu

1998, 19(S1):  295-296. 

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As a versatile three-carbon syntho,α-oxoketene cyclic acetals 1 have been applied in many fields. In order to study the structure and application of 1, we performed that α-aroyl-α-acetyl ketene cyclic dithioacetals 2 or 3 condensed with aromatic aldehydes catalyzed by sodium ethoxide and fifteen new condensation products 4 and 5 were obtained.

SYNTHESIS OF CHIRAL DERIVATIZATION REAGENT L-SERINE METHYLESTER HYDROCHLORIDE SALT

Xu Xiuzhu, Xu Genliang

1998, 19(S1):  297-297. 

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In order to increase stereoselective activity of pharmaceuticals, decrease side effects from the use of medecines and monitor the quality control in drug production, analysts have shown universal solicitude for optical separation^[1].

Synthesis and Identification of 2-(4-hydroxyphenoxy) Propionic Acid

Shi jie-hua, Xu Xiu-zhu

1998, 19(S1):  298-299. 

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The synthesis of 2-(4-hydroxyphenoxy) propionic acid, useful as an important intermediate for herbicides, had been reported^[1-3]. In this paper, The synthesis of 2-(4-hydroxyphenoxy)propionic acid had been studied by the reacting hydroquinone with cheap 2-chloropropionic acid in the presence of base.

Synthesis and Characterization of 1-[2-(N,N-dimethyl-amino)ethyl]-1H-tetrazol-5-thiol

Zhu Yifeng, Shan shang, Xu Hongyuan, Shi Mingxiao

1998, 19(S1):  300-301. 

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l-[2-(N,N-dimethyl-amino)ethyl]-1H-tetrazol-5-thiol is an important intermediate.It is widely used as cephalosporin C_S derivative.This paper has developed a new synthetic pathway to give it by six steps.The experimental procedures are shown the following.

Synthesis and Characterization of 2-[(3-Aminophenyl)sulfonyl] ethanol Hydrogen Sulfate

Shan Shang, Zhu Yifeng, Hu Gengyuan

1998, 19(S1):  302-303. 

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2-[(3-Aminophenyl)sulfonyl] ethanol hydrogen sulfate (APSES) is an important intermediate for reactive dyes.It can be used to synthesize KN type reactive dyes, which have broad colour spectra,good water solubility, excellent adaptability for different dye technique,etc. Synthesis of APSES were currently developed by Kato Kuniok et al^[1] and Sanki^[2].Kato had attempted to synthesize of APSES by reaction of sodium benzenesulfinate as raw material with ethylene oxide to obtain 2-phenylsulfonyl ethanol(PSE). The PSE could further be nitrated and hydrogenated to obtain 2-[(3-aminophenyl)sulfonyl]ethanol (APSE). Finally,APSE was reacted with oleum to obtain 2-[(3-aminophenyl) sulfonyl] ethanol hydrogen sulfate (APSES). Sanki had discoved a new synthetic method for the PSE. The PSE was prepared by first reaction of thiophenol as raw material with chloroethanol, and then by oxidation with hydrogen peroxide.The above mentioned two methods are not easily be adopted in industries at home. The shortage and cost of the thiophenol and sodium benzenesulfinate are mainly limited. We modificated a new synthetic pathway for APSES by five steps. The experimental procedures are shown the following.

Syntheses of Chiral Fused Heterocyclic Compounds Containing l,2,4-Triazole Ring

Wang Zhongyi, You Lingfeng, You Tianpa, Shi Haijian, Shi Haoxin

1998, 19(S1):  308-309. 

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The chemistry of life is based considerably on chirality. Consequently, stereospecificity has to be regarded as an especially important characteristic of biological systems. The influence of stereospecificity of the biological activities of enzyme inhibitors or compounds binding to receptor is a well known fact in the field of drug action^[1]. s-Triazoles and l,3,4-thiadiazoles are reported to exhibit broad spectrum of biological and pesticidal activities^[2-3].In recent years, bridge head nitrogen heterocycles have received much attention as anthelmintic agents, however, it is not observed that the syntheses of chiral fused heterocyclic compounds containing s-triazoles and l,3,4-thiadiazoles. In order to study the relationship between stereochemistry and the performance of fungicides, we have synthesized a series of (s)-1,2-di(3-aryl-s-triazolo[3,4-b][1,3,4] thiadiazolo-6-yl) ethylamine and (s)-1-(3-aryl-s-triazolo[3,4-b][l,3,4] thiadiazolo-6-yl) ethylamine by the condensation of 3-aryl-4-amino-5-mercapto-1,2,4-triazoles with L-aspartic acid and L-alanine in the presence of phosphorusoxychloride.

Synthetic and Conformational Studies of Bridged β-Cyclodextrin Dimers

Xiao-Qi Zheng, Qing-Xiang Guo, Li Yang, You-Cheng Liu

1998, 19(S1):  310-311. 

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Cyclodextrins (CD) have been found wide applications in the artificial enzymes^[1] due to their ability of recognizing and binding a variety of organic and inorganic substrates in aqueous solution. In some cases, however, their binding capacity and selectivity are not good enough to make them useful (K_a~10²-10⁴L/mol). Breslow et.al^[2,3] have reported that the bridged cyclodextrin dimers can complex some kinds of substrates strongly (K_a~10⁶-10¹¹L/mol) because of their more recognition sites. Recently, we synthesized a series of bridged β-CD dimers. It has been observed that the conformation of the dimers changed markedly upon the solvents.

Mechanism of Reduction of 1,1-Dinitro-2,2-diphenylethylene by 1-Benzyl-1,4-dihydronicotinamide

Hong-Yi Wang, Xiao-Qing Zhu, You-Cheng Liu, Shi-Dong Chu, Qing-Xiang Guo

1998, 19(S1):  312-313. 

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1-Benzyl-1,4-dihydronicotinamide (BNAH) is widely used as a model to mimic coenzyme NAD(P)H reductions¹. The interest continues in distinguishing whether the formal hydride transfer from BNAH to the substrate takes place by a one-step hydride transfer or by an e-H⁺-e or e-H sequence^2,3.

N-Arylimine 1,4-Cycloaddition Reaction. Preparation of Substituted Hexahydrofuro[3,2c] Quinolines from Shiff Bases and 2,3-Dihydrofuran

Jun ZHAO, Shu Feng CHEN, Xiao Tian LIANG

1998, 19(S1):  314-315. 

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The synthesis of nitrogen heterocycles through cycloaddition reaction of imines has stimulated much preparative and mechanistic work. ^1,2The reaction of Shiff bases with electro-rich olefins has been utilized for the systhesis of quinoline derivatives. ³This paper introduces Lewis acid catalyzed cycloaddition reactions of N-arylideneaniline(Ⅰ) with 2,3-dihydrofuran(Ⅱ), which gives a pair of epimers dl-2,3,3a,4,5,9b-hexahydro-4-arylfuro[3,2-c]quinolines (Ⅲ and Ⅲ') and a few of their corresponding aromatized compounds.(Ⅳ)

A Novel Desilylating Method for tert-Butyldimethylsilyl,tert-Butyldiphenylsilyl and Triisopropylsilyl Ethers

Adam Shih-Yuan Lee, Jiun-Jie Shie, Hsiu-Chih Yeh

1998, 19(S1):  316-316. 

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In order to synthesize complicated medicinal compounds, chemists have developed increasingly satisfactory protective groups and effective methods for the formation and cleavage of protected compounds. The selective method to remove protective groups is an important tool in organic synthesis. Transformation of an alcohol to its corresponding silyl ether is a common and useful method for protecting hydroxyl groups. Within the silyl ethers,tert-butyldimethylsilyl,tert-butyldiphenylsilyl and triisopropylsilyl ethers are the most commonly used protecting groups. The cleavage of the Si-O bonds of these silyl ethers is typically performed with fluoride ion or under harsh acidic or basic conditions. Herewith, we wish to report a highly efficient and mildly acidic desilylating method for tert-butyldimethylsilyl,tert-butyldiphenylsilyl and triisopropylsilyl ethers.

Thiophenes from Dienediones

Chi Wi Ong, Po Chuen Shieh

1998, 19(S1):  317-317. 

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Our previous studies have demonstrate the usefulness of dienedione as versatile intermediates for the synthesis of cyclopentenone and arylfuran. The dienedione moiety may serve as a four carbon unit which can undergo consecutive nucleophilic addition reaction to form heterocycles. Herein we report our investigation on the addition of sulfur to the four carbon unit of dienedione for the synthesis of 2,5-disubstituted thiophenes. The regioselectivity of the reaction under various conditions will also be discussed.

Synthesis of 4-phenylethoxyquinazoline Fungicides/Insecticides

J. Tai, G. Roth, J. Ringer, W. Wu

1998, 19(S1):  318-318. 

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Recently, 4-phenylethoxyquinzoline and its analogues have been found to have both fungicidal and insecticidal activities. The synthesis of these compounds involves the construction of the quinazoline ring, preparation of the side chain, and coupling the side chain with 4-chloroquinazoline and its analogs.

Organometallic Chemistry

Characterization of Mass Spectra of Isomeric Dodecenols

Xiao Junhua, Wu Haifeng, Wang Guijie, Yuan Gu

1998, 19(S1):  319-320. 

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The components of some insect sex pheromones are aliphatic long-chain unsaturated acetates, alcohols and aldehydes. For example, some isomers of dodecenols are the main components of sex pheromones of some noctuid moths (Δ7), olethreutine species (Δ8 and Δ9)¹ and so on. Identification of the structure, especially the position of the double bond, is a very important job. GC-MS is a good method to analyze the ng quantity of sample, which is the level of nature sex pheromones. However, the double bond of straight olefinic components has a strong tendency to migrate along the carbon chain prior to fragmentation under electron impact ionization conditions. So the spectra of isomers are very similar and difficult to be identified by the normal mass spectrometry. In this paper, we develop a new method to identify the isomers of dodecenol based on the sum of the intensity ratios of pairs of fragments.

Study on Reactivity of Five-co-ordinate Bicycloazastannoxides. Ⅲ. Bromination with Bromine

Yang Xiao Ping, Wang Ji Tao

1998, 19(S1):  321-322. 

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In earlier our studies, we have determined that the structure of pentacoordinate bicycloazastannoxides with Schifibase derived from amino acids is similar to that of the metal vitamin B₆ chelates by X-ray method[l-3]. Recently we investigated the condensation of pentacoordinate bicycloazastannoxides with aldehydes[4] and first determined the thermodynamic α-CH acidity (pKa value) of pentacoordinate bicycloazastannoxides by the accurate spectrophotometeric method for relative equilibrium acidities of weak carbon acids in dimethyl sulfoxide[5]. It was found that the effect of the effect of α-CH acidity and stability of α-carbanions on condensation is important. The bulkiness of the amino acid moieties affects the α-CH acidity directly, and the effect of the bulkiness of amino acid moieties on.their α-CH acidities was interpreted by the Taft equation.

Study on Reactivity of Five-co-ordinate Bicycloazastannoxides.IV. Michael Addition with Activated Olefins

Yang Xiao Ping, Wang Ji Tao

1998, 19(S1):  323-324. 

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In view of the large number of vitamin B₆ related enzymes, one of the important features of the mechanism is the formation of an α-carbanion in the presence of a base catalyst[l,2]. The α-position may be the active site of the enzyme. As known, the most popular synthetic route consists of the conversion of a suitable derivation into a carbanion, followed by reaction with an electrophile. For five-co-ordinate bicycloazastannoxides, the coordination between a metal Sn atom and a Schifibase ligand increases the αCH acidity and stabilized the incipient carbanion[4]. But their electrophilic reactions on α-position have received less attention[3].

Sythesis of Novel O-(Alkylamido-phenyl) phos phoryl choline as Phospholipase A₂ Inhibitors

Yin Wang, Gui Jun Yu, Zhai Ming Zhu, Wen Sheng Guo, Yan Liu

1998, 19(S1):  325-326. 

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Some novel O-(Alkylamido-phenyl) phosphorylcholines were synthesized, and their construction were confirmed with IR and ¹H NMR. Some of them have the property of inhibiting the phospholipase A₂.

Effect of Axial Ligands on Monooxygenation of Cyclohexane Catalyzed by A Dimanganese Schiff Base Complex

CHEN Xin-Bin, GUI Ming-De, ZHU Shen-Jie

1998, 19(S1):  330-331. 

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There are many dimetalloenzymes in nature^[1]. To mimic these enzymes, we synthesized a new dimanganese Schiff base complex-Bis[N,N'-ethylene-2,2,-(phenylmethylene)-bis(3,4-dimethylpyrrole-5-aldimino)] dimanganese Mn₂L (shown in Fig.1). Its structure was confirmed by IR, UV-Vis, ¹HNMR and elemental analysis. It can catalyze monooxygenation of cyclohexane with PhIO as an oxidant.

Synthesis and Characterization of Some Novel Organochromium Fullerene-C₆₀ Derivatives

Song Li-Cheng, Zhu Ying-Huai, Liu Pong-Chung, Tian Jian-Guo, Li Ga

1998, 19(S1):  334-335. 

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Although the organotransition metal fullerene-C₆₀ derivatives have been intensively studied, no report regarding organochromium complexes containing a direct chromium to C₆₀ bond has appeared in literatures.¹ Now, we report preliminarily the synthesis, characterization and properties of the first such chromium complexes, namely single isomer fac-Cr(CO)₃(dppe)(η²-C₆₀) and the isomer mixture of fac- and mer-Cr(CO)₃(dppe)(η²-C₆₀).

Synthesis and Structure of a novel Fullerene[C₆₀] derivative covalently linked to five ferrocenylmethylimino Substituents

Ying-Huai Zhu, Li-Cheng Song

1998, 19(S1):  336-337. 

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The Synthesis of a fullerene[C₆₀] derivative[CpFeC₅H₄CH₂N]₅C₆₀ is described, Spectroscopic evidence suggests its five CpFeC₅H₄CH₂N moietes being bonded to five parallel[6,6] bonds across the equatorical plane of fullerene[C₆₀]to give a gear-like structure.

Synthesis and Structure of the first cationic ferrocene C₆₀ derivative

Ying-Huai Zhu, Li-Cheng Song

1998, 19(S1):  338-339. 

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The first cationic ferrocene C₆₀ derivative[CpFe(CO)₂]₄⁺C₆₀[BF₄]₄^- was synthesized by a new route involving substitution of the loose ligand C₃H₆ by C₆₀ and characterized by EA, ¹HNMR, FAB-MS, IR and UV-vis spectrum. The new air-sensitive compound has a D_2h symmetry.

Reaction of 1,2-bis(cyclopentadienyl)tetramethyl digermane with Ru₃(CO)₁₂

Yongqiang Zhang, Baiquan Wang, Shansheng Xu, Xiuzhong Zhou

1998, 19(S1):  340-341. 

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We have recently reported a novel rearrangement reaction involving an intramolecular metathesis between M-M and Fe-Fe bonds in the dinuclear iron complexes (Me₂MMMe₂)[η⁵-C₅R₄)Fe(CO)]₂(μ-CO)₂ (M=Si, Ge; R=H, Me):^[1-5].In order to extend the applied range of the rearrangement reaction we tried to synthesize the digermyl briged diruthenium analogues. The results showed a great difference between them.

Electrochemical behavior of alkyl-bridged biferrocene derivatives

Yao-feng Yuan, Ling-yun Zhang, Ai-guo Hu, Wan-yi Liu, Zhong Cao, Ji-tao Wang

1998, 19(S1):  342-342. 

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Compounds containing two or more ferrocenyl groups are well-known precursors for mix-valent compounds[1-2]. It was believed that the interaction between the ferrocenyl groups are facilitated by the conjugate bridge between them. Many such researches were reported. In this paper, we report the electrochemical behavior of alkyl-bridged biferrocene, their acylation derivatives and corresponding reduction products, and transition metal complexes with alkyl-bridged biferrocenyl aryl hydrazone and β-alkyl-bridged-α,β-unsaturated ketones. Though the bridging alkyl group prevents conjugation between the two ferrocenyl group, they show characteristics of mix-valence species. The extent of interaction between the two ferrocenyl groups is influenced by the distance between the iron atoms, the substituents on the cyclopentadienyl ring, transition metal ions and their coordination modes.

Intramolecular hydrogen bonding studies in mono-, bis and poly-[N-formyl-N'-aryl(alkyl) substituted thiourea] ferrocene derivatives

Yao-feng Yuan, Ling-yun Zhang, Ai-guo Hu, Su-ming Ye, Bin Wang, Ji-tao Wang

1998, 19(S1):  343-344. 

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For several years, we have been engaged in the synthesis and coordination chemistry of ferrocenyl-containing acyl thiourea derivatives[1-2].The existence of intramolecular hydrogen bond is another interesting problem to be investigated. A series of ferrocene derivatives containing N-formyl-N'-aryl (alkyl) thiourea side chains were synthesized by treating mono- or bis ferrocenoyl isothiocyanate with various amines. It was found that intramolecular hydrogen bond between the carbonyl oxygen and the hydrogen atom on N' is common in this kind of compound. The introduction of a ferrocene fragment into the molecule often leads to its better crystallizability.

Synthesis, structures and reactivities of poly(pyrazol-1-yl) alkane tetracarbonylmolybdenum (tungsten):x-ray crystal structures of (CH₂)₂(3,5-Me₂Pz)₂W(CO)₄ and CH₂(3,5-Me₂Pz)₂W(Cl)(CO)₃(SnCl₃)(Pz:pyrazolyl)

Tang Liangfu, Xu Yuming, Wang Zhihong, Wang Jitao

1998, 19(S1):  345-346. 

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Since S. Trofimenko introduced these isosteric and isoelectronic ligands with poly(1-pyrazolyl)borates^[1],the poly (pyrazolyl)alkane ligands have attracted much attention. Their coordinating behaviour with transition and main group metals has been extensively investigated in recent years^[2]. The coordinating behaviour of bis(3,5-dimethylpyrazol-1-yl)ethane is often different from other poly(pyrazolyl) alkanes^[3]. The VIB metals carbonyl complexes bonded with poly (pyrazolyl)alkanes have novel structures and unusual reactivities^[4,5,6],which encourages us to investigate M-Sn bimetallic complexes with poly(pyrazolyl)alkanes. In this paper, we report the synthesis, characterization and reactivities of poly (pyrazol-1-yl)alkane tetracarbonylmolybdenum (tungsten) with R'SnCl₃(R'=Ph,Cl).

AN EFFICIENT SYNTHESIS OF ALIPHATIC α-ORGANOTHIO ALDOXIME

Xin Liu, RuiLan Shao, RunQiu Huang

1998, 19(S1):  347-348. 

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The importance of the aliphatic α-organothio aldoxime compound 3 in the preparation of various pesticides is well established. Molecules comprising the α-organothio oxime moiety have been reported to exhibit insecticidal,nematocidal,miticidal activities.^[1-2] In the synthesis of the compound 3,the chlorination of the corresponding aliphatic aldoxime 1 is the key step.In conventional methods, the aliphatic aldoxime 1 is chlorinated by chlorine,then the resulting hydroxime acid chloride 2 is treated with sodium alkyl mercaptide to obtain the desired compounds 3^[3]. Although free Cl₂ is the most common chlorinating agent,it is laborious to determine the accurate amount that has been absorbed,and the high reactivity of Cl₂ always leads to side reactions. In connection with an our ongoing research project, we require an efficient and simple method for the synthesis of the compound 3.An improved synthesis process according to the following scheme is reported in this paper.

Synthesis of Phosphorus Derivatives of Pyrazolo[3,4-d]pyrimidine

Li Zaiguo, Huang Runqiu, Li Huiying, Liu Xin

1998, 19(S1):  349-350. 

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Pyrazolo[3.4-d]pyrimidines are of considerable chemical and pharmacological importance as purine analogs^[1]. Various related compounds of these also show anti-tumor, anti-leukemic and antiviral activities^[2,3]. In addition,α-aminoalkylphosphonic acid are well known for their wide range of biological activities. They serve in agrochemistry as antifungal agents, herbicides and plant regulators^[4]. Recently, it was discovered that some derivatives of α-aminoalkylphosphonic acid also exhibit good antiphytoviral activity^[5]. As an extension of our studies on plant virucides, we now wish to report the synthesis of some novel phosphorus derivatives of pyrazolo[3,4-d]pyrimidine-6-ones 4,which may have antiviral activity.

Synthesis of 3-(α-Phenyl-phosphonomethyl)-quinazoline-2,4(1H,3H)-diones

Li Zaiguo, Huang Runqiu, Li Huiying, Liu Xin

1998, 19(S1):  351-352. 

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α-Aminoalkylphosphonic acids have attracted much attention due to their wide range of biological activities. They serve for inhibiting enzyme activity, bacterial growth and in agrochemistry as antifungal agents, herbicides and plant regulators^[1]. In a recent report, α-aminoalkylphosphonates showed very good inhibitory effects against plant virus^[2]. At the same time, some derivatives of quinazoline-2,4(1H,3H)-dione also exhibit antiphytoviral activity^[3,4]. Considering the wide applications of such compounds, we designed to synthesize some novel quinazoline-2,4(1H,3H)-diones with α-amino-alkylphosphonates moiety, e.g. 3-(α-phenyl-phosphonomethyl)quinazoline-2,4(1H,3H)-dione 4 (scheme Ⅰ).

Synthesis and Characterization of Solid Supports Containing silicon

Li Jing, Liao Xiangjun, Liu Hua, Xie Qinglan, Zhao Jun

1998, 19(S1):  353-354. 

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Combinatorial chemistry has been a new field of chemistry since 1990's.^[1][2] More than 90% of researchers play their emphases on the studies of the solid supports such as P-(CH₂)_n-N and P-(CH₂)_n-O(n=1,2,3), but only a couple researchers play their emphases on the studies of the P-(CH₂)_n-Si(n=1,2,3). Because of the characteristic of the Si-Ar bond, we devise a series of the solid supports containing Si-Ar bond.These solid supports containing silicon were synthesized in two methods. At the same time,we also synthesized the monomer of the solid supports containing silicon or tin. The structures of these compounds were characterized by IR, elemental analysis.The synthetic routes of the solid supports containing silicon are shown in scheme 1 and the synthetic routes of the monomer of the solid supports containing silicon or tin are shown in scheme 2.

Synthese,Structure and Acaricidal Activity of Triorganyl Chlorostannanes/Containing Silicon

Liu Hua, Chen Xue-Ren, Wang Ji-Tao, Xie Qing-Lan, Li Jing

1998, 19(S1):  355-355. 

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The drug molecule is called as silα-drug if one carbon atom is substituted by silicon atom in the organic-drugs. Generally, drugs of this kind have low toxicity and pro-long efficiency. People have designed many methods in order to decrease the toxicity of organotin compounds and organosilicon has proved to be effective. Torque^[1] is a new acaricide made by Shell company in America, its structure is[(PhMe₂CCH₂)₃SnI₂O. R. Tacke^[2] from Germany synthesized the compounds (PhMe₂SiCH₂)₃SnX[X=HO, (PhMe₂SiCH₂)₃SnO] and tested the acaricidal activity of[(PhMe₂EICH₂)₃Sn]₂O (EI=C, Si) in 1986. He proved that the silyl-derivatives of Torque were highly effective acaricides.

Synthesis of Novel Organogermanium Sesquioxides and Reactivities of 3-(Trichlorogermyl)propanoic Acid

Wang Qingmin, Zeng Xianshun, Cui Tao, Zeng Qiang

1998, 19(S1):  356-357. 

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During the past two decades, carboxyethylgermanium sesquioxide Ge-132[O₃(GeCH₂CH₂COOH)₂] and its derivatives have attracted considerable attention because these organogermanium sesquioxides exhibited anticancer activities[1,2]. In 1993, Kurono et al. have synthesized phosphonoethylgermanium sesquioxide[O_3/2GeCH₂CH₂PO(OH)₂], which possesses higher antitumor activity than Ge-132[3]. Encouraged by these promising results, we developed the idea that the incorporation of a germanium residue into α-aminophosphonic acids and their derivatives, which have antibacteria and antitumor activities[4,5], would enhance their antitumor activities to a significant degree, while their toxicity would be reduced at the same time. Therefore, we designed and synthesized a series of novel organogermanium sesquioxides containing α-aminophosphonate groups by the hydrolysis of O,O-diphenyl N-trichlorogermyl propiono-α-aminophosphonates.

Synthesis of Novel Organogermanium Compounds containing Phosphoryl Groups and Bioactivities of Products

Wang Qingmin, Zeng Xianshun, Cui Tao, Zeng Qiang

1998, 19(S1):  358-359. 

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The β-trialkylgermanyl propanoic acid、β-triphenylgermanyl propanoic acid and their derivatives exhibit anti-inflaxnmatory and antibacteria activities[1]. And both phosphonic acids and their derivatives have bioactivities, e.g. antibacteria[2]、antitumor[3],etc. But synthesis and bioactivities of organogermanium compounds containing phosphoryl structures have seldom been reported. In order to look for new compounds having potent efficient anticancer and antiinflammatory activities, We designed and synthesized organogermanium compounds containing phosphoryl groups Ⅰ and Ⅱ,and studied the methods of synthesis, as well as structures and properties of the products.

Synthesis and crystal structure of a novel mercapto-organotin complex:[Et₃NH][Ph₂SnCl(μ²-SCH₂COO-)]

Xueqing Song, Qinglan Xie, Jing Li, Xiaoniu Fang

1998, 19(S1):  360-360. 

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A novel complex[Et₃NH][Ph₂SnCl(μ²-SCH₂COO-)],has been unexpectedly obtained by the reaction of Ph₃SnCl and HSCH₂COOH in 2:1 molar ratio in the presence of organic base Et₃N.

Synthesis, structures and in vitro anticancer activity of some germanium-substituted di-n-butyltin dipropionates

Xueqing Song, Zhiqiang Yang, Qinglan Xie, Jinshan Li, Xiaoniu Fang

1998, 19(S1):  361-361. 

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Organotin and organogermanium compounds are extensively studied for their wide range of biological activity. To link biological active properties of organotin and organogermanium, sixteen new germanium-substituted di-n-butyltin dipropionates with the form (R₃GeCHR¹CHR²COO)₂SnBu₂ⁿ·H₂O were synthesized.

Cp₂TiCl₂/M(Zn,Mg) system promoted the addition reactions, enyne cyclization reactions and applied in the synthesis of (+)-Goniopypyrone

Hong-ming Li, Hong-Liang Sun, Zong-Bao Zhao, Yi-Ke Ni, Chang-Qing Wei, Gao-sheng Yang, Min Yang, Gang Zhao, Yu Ding

1998, 19(S1):  366-366. 

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In the course of our ongoing projects. It has been focused on the studies of carbon-carbon formation using redox system such as Cp₂TiCl₂/M(Zn,Mg) and LnCl₃/Zn. This paper deals with our research progess on exploring reactions for the syntheses of useful building block, intermediates and natural products.

Study on the α-Thiocarbonylthioformamide Ⅰ-Comparison with α-carbonylthioformamide

Jian Ping Zou, Zhong E Lu, Run Sun Zeng, Bei Zhao, Ke Qian Ghen

1998, 19(S1):  367-368. 

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α-Carbonylthioformamide 1 and α-thiocarbonylthioformamide 1 were synthesized by Adiwidjaja in 1980¹. However, there is no report of these compounds related their properties and reaction activities². Compound 1 has two possible sites for nucleophilic attack. In our previous works., it was used to synthesize a lot of heterocyclic compounds (Scheme l)^3-6.

Study on'the α-Thiocarbonylthioformamide Ⅱ——Dehydrogenation of tetrahydronaphthalene

Run Sun Zeng, Jian Ping Zou, Zhong E Lu, Jian Feng Ge, Ke Qian Chen

1998, 19(S1):  369-370. 

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α-Thiocarbonylthioformamides were synthesized in 1980^[1-3]. Authors first explored their dehydrogenation reaction at high temperature. In our initial experiment, α-Thiobenzoylthioformmorpholine(l) was heated with diethyl acetylene dicarboxylate in tetrahydronaphthalene(2). The reaction is shown as following.

Study on the α-Thiocarbonylthioformamide Ⅲ——Reaction with trimethyl phosphite

Run Sun Zeng, Jian Ping Zou, Zhong E Lu, Xiang Shan Wang, Ke Qian Chen

1998, 19(S1):  371-372. 

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α-Thiocarbonylthioformamide is a stable and almost unexplored class of compounds¹ which attracts us to study their properties and reactions. According to literature three-valenced phosphorus compound is easy to react with thiirane² and thiocarbonate³ to form C=C double bond. So we want to explore the reaction of α-thiocarbonylthioformamide with three-valenced phosphorus compound. In initial experiment, we explored the reaction of α-thiobenzoylthioformmorpholine (1a) with trimethyl phosphite in dry diethyl ether at room temperature.

Study on the Reaction of α-Ketohemithioacetal

Jian Ping ZOU, Run Sheng ZENG, Li Hua QIU, Bei Zhao, Ke Qian Chen

1998, 19(S1):  373-374. 

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Aromatic α-sulfinyl carboxylic acids can be rearranged to hemithioacetals or other derivatives of glyoxylic acid under the action of acid reagents was first reported by Pummerer¹. Later, Russell and coworkers applied this rearrangement to β-ketosulfoxides, synthesized α-ketohemithioacetal², which can be transformed to α-keto alcohol, α-keto aldehyde and α-hydroxy alcohol, α-hydroxy acid³. Furthermore, Hall and Poet reported that α-ketohemithio-acetal can be rearranged to the corresponding α-hydroxythioester in the presence of magnesium nitrate and sodium acetate or tertiary amine⁴. However, few reports of reaction of α-ketohemithioacetal can be seen in literature.

Synthesis and Spectroscopic Characterization of Transition Metal Complexes of Maleionitriledithiolate and 4,4'-Dimethano-2,2'-bipyridine

PENG Zheng-he, FANG Chen-jie, PAN Qing-cai, WEI Yi-hai, QIN Zi-bin

1998, 19(S1):  375-376. 

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Transition metal complexes with a tetragonal planar structure of a dithiolene and a diimine have excellent electronic functions due to the intramolecular charge transfer from a ligand to other ligand (LL'CT)^[1-3]. Our interest is in the metal complexes of the dicyno-dithiolene and some diimine such as substituted and unsubstituted phenanthrolines and bipyridines. In the present work we studied synthesis, characterization, photo-physical and photochemical properties of the title complexes M(mnt)(dmbpy),M=Mn^Ⅱ,Fe^Ⅱ,Co^Ⅱ, Ni^Ⅱ, Cu^Ⅱ,Zn^Ⅱ.

Synthesis and Spectroscopic Characterization of Transition Metal Complexes of Maleionitriledithiolate and 5-Nitro-Phenanthroline

PENG Zheng-he, PAN Qing-cai, REN Xiao-ming, FANG Chen-jie, QIN Zi-bin

1998, 19(S1):  377-378. 

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The dithiolenes and diimines and their metal complexes are an important research field in the organic and coordination chemistry^[1-3]. Transition metal complexes of a dithiolene and a diimine have excellent electronic functions due to the intramolecular charge transfer from a ligand to other ligand (LL'CT)^[3], in which are interested authors^[4,5]. Recently we have been studied in detail the synthesis and properties of the title complexes M(mnt)(5-NO₂-phen), M=Mn^Ⅱ, Fe^Ⅱ, Co^Ⅱ, Ni^Ⅱ, Cu^Ⅱ, Zn^Ⅱ. The structure and properties of the M(mnt)(5-NO₂-phen) were characterized by the elemental analysis, TDA-TG, MASS, IR, UV-Vis, fluorescence and EPR spectra,molar conductivity and magnetic susceptibility. In the present abstract we report only the synthesis and spectroscopic characterization of these complexes.

Theoretical Studies on Copper, Nickel Complexes of Corrole and Isocorrole

Di-Fei Wang, Kyle W. K.. Chan, Yun-Dong Wu, Emanuel Vogel

1998, 19(S1):  379-380. 

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Corrole 2, an analogue of porphyrin 1, is also a fascinating molecule. It can be considered as an intermediate in the biosynthesis of corrin 3,the chromophore of Vitamin B₁₂, Similar to porphyrin, corrole also has 18 electrons in the π-system of the ring and is aromatic. Recently, isocorrole 4, another compound in the corrole family, was synthesized by Vogel's group^[1].One important feature of corrole and isocorrole is the possible formation of tri-anion, and thus the ability to stabilise high-oxidation-state metal cations.

Resolution of Cycloplatinated Ferrocenylketimines

Wu Yang-Jie, Ding Li, Wang Wen-Ling, Du Chen-Xia, Song Qiu-Ling

1998, 19(S1):  381-382. 

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Ferrocene derivatives especially the chiral and optically active 1,2-disubstituted ferrocenes are the most extensively investigated metallocenes. The common way to obtain the planar chirality in the ferrocene moiety is the usage of a chiral precursor. Sokolov et al have reported the asymmetric cyclopalladation with the salts of optically active carboxylic acids as nucleophilic catalysts, however, this method was suitable only when the reaction experienced the diastereomeric transition states^[1]. The only report,of the resolution of cyclometallated ferrocene derivatives was given by Nonoyama and his coworkers^[2]. They resolved dimethyl-aminomethylferrocene to optically pure enantiomers using the (S)-proline as chiral auxiliary and separated the diastereomers by solubility difference.

Red Light Emitting Devices Based on Organo-lanthanide(Ⅲ) Complex

Yu Gui, Wu Xia, Liu Yunqi, Wang Mingzhao, Ji Linpei, Zhu Daoben

1998, 19(S1):  383-384. 

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An organic electroluminescent devices with Eu³⁺-complex as an emitter was fabricated. A device structure of ITO/emitting/electron transport layer/Al was empolyed. Its color was red.

Physical Organic Chemistry

CAGED CHOLINERGIC LIGANDS AND PHOTOREGULATION OF CHOLINESTERASE ACTIVITIES

Ling Peng, Maurice Goeldner

1998, 19(S1):  385-385. 

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Photolabile precursors of biologically interesting molecules, or "caged" compounds can provide control of temporal and spatial release of desired molecules by rapid photolysis, and are thus important tools in the study of fast biological processes. Acetylcholinesterase (AChE) is a particularly fast enzynie which hydrolyses the neurotransmitter acetylcholine with a turnover number approaching 20000 s^-1. Knowledge of the 3-D structure of AChE[1] has permitted a better understanding of structure-function relationships in the cholinesterases, but has also raised cogent new questions concerning the traffic of substrate and products to and from the active site. Time-resolved crystallography would present an ideal approach to investigate this issue at the atomic level and in real time,provided that suitable probes, which regulate the enzymatic activity by temporally and spatially controled release of enzyme substrates or product.

The Anomalous Triplet Exciplex Emission of 4-phenylbenzophenones with Amines

Chch-Yung Liu, Tai-Shan Fang

1998, 19(S1):  386-387. 

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Structured phosophorescence with 20μs life time[480nm, 510nm (max),550nm] from 4-phenyl-benzophenone (4-PBP) was quenched by trieyhylamine (TEA) in benzene. An Anomalous exciplex emission with strutureless peaking at 647nm and 30μs life time. A quenching mechanism has been shown to involve a mixed (π,π^*) and (n,π^*) triplet of 4-PBP to form an exciplex with the grond state of TEA.

Application of P-31 NMR to the Study of Phosphorylated/Cellulose and Lignocellulosic Materials(Wood)

Chen-lan Wang

1998, 19(S1):  388-388. 

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Phosphorylation of cellulose and wood(also named as lignocellulosic material) is one of the potential methods for chemical modification of these natural polymers. In this research, α-cellulose and wood meals (extracts free) were mixed with certain organophosphoryl chloride compounds, producing the corresponding phosphorylated derivatives. A series of model chemicals (e.g. ethylene glycol, glucose, cellobiose, phenols,guaiacol, etc.) were converted to the same derivatives as references. The phosphorylated products were examined by using P-31 NMR spectroscopy to analyze their structural characteristics.

The constituents of the South American liverwort Lepicolea ochroleuca

Huei-Ju Liu, Chia-Li Wu, J. Zapp, Hans Beeker

1998, 19(S1):  389-389. 

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Ten terpenoids _1-10 were isolated from the South American liverwort Lepicolea ochroleuca, collected at Chile, South America. Compounds 1 and 2 were the major components and the others were just minor. Among them, compounds 8-10 were novel. Their structures were established by spectral analysis.

SOME INTERESTING FINDINGS FROM TAIWANESE LIVERWORTS

Chia-Li Wu, Huei-Ju Liu, Ran-Chien Chang, Yi-Wei Chen, Chung-Shing Liou

1998, 19(S1):  390-390. 

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Here we wish to report some interesting new compounds identified from our recent studies on the constituents of liverworts from Taiwan.

Screening of Antioxidants and Antiozonants and Their Protection Mechanisms

Xian-Man Zhang

1998, 19(S1):  391-392. 

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Antioxidants and antiozonants have been widely used in polymer industry because addition of a small amount of antioxidants and/or antiozonants could prevent the degradation caused by oxygen and/or ozone from atmospheric air and significantly increase the service life-time of polymer products.¹ The related degradation is also responsible for foodstuff deterioration, and for ageing and cancer of the biological systems.^1b

3D-SAR And A novel Molecular Pharmacology Model of Cholinergic And Anticholinergic Drugs

Wenxiang HU, Liuhcmg YUN, Jianying WANG, Jianshe WANG, Shengjian TAN

1998, 19(S1):  401-402. 

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Anticholinergic drugs have been widely used for many years in neurological research field and clinicial therapy of many dieases, such as parkinsonism stomachache and the organophosphorus agents poisoning. It is important that investigating the conformation-activity relationship (CAR), 3D-QSAR and molecular pharmacology of these compounds to aid in die design highly selective drugs and explain many phenomena understood difficultly,including the similar biological effects for various compounds and different effects for a single compound.

Substituent Effects And Structure-Reactivity Relationship of Organophosphorus Compounds

Wenxiang HU, Chengye YUAN, Shushen LI, Jianying WANG

1998, 19(S1):  403-404. 

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To evaluate the substituent effect in organophosphorus compounds, a series of model compounds, namely 4-substituted-2,6,7-trioxa-1-phosphabicyclo[2.2.2] octane-1-oxides, alkyl hydrogen p-substituted phenyl-phosphonates, dialkyl p-substituted phenylphosphonates, as well as alkyl hydrogen alkylphosphonates, were synthesized and studied. Since in these compounds the substituents are located far away from reaction centre and the contribution of the steric effect of substituents can thus be eliminated, the substituent polar effect was evaluated based on ³¹P NMR, pKa and charge density of phosphoryl oxygen of these compounds calculated by the quantum mechanies MNDO method. The results showed that the polar effects of substituent in carboxylic and organophosphorus esters are similar, and the variation in polar effect among the alkyl groups is not significant. In the meantime, some steric parameters E_s^p of substituents were suggested for organophosphorus compounds, which are different from the Taft's E_s and Charton's υ parameters^[1,2].

Determination of Aldehydes and Ketones Pollutants in Ambient and Polluted Air by HPLC with Precolumn Chemical Derivatization

Qingtao PENG, Wenxiang HU, Runwu CAO

1998, 19(S1):  405-406. 

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In the last years, aldehydes and ketones have been the pollutants constantly in air with the development of the chemical industry. Most of aldehydes and ketones are toxic or carcinogenic. There are six carbonyl compounds in the pollutants with the maximum permission concentration, which limited by our state standard in residential area, workshop air and surface water formulated in 1979. In New Clean Air Act of America, there are 189 toxic and harmful pollutants including nine carbonyl compounds.Therefore, it is extremely necessary to study the sampling process and analytical method of aldehydes and ketones. At present, the main domestic analytical methods are colorimetric method and titrimetric method. In addition, ion chromatography and gas chromatography are also adopted. These methods can only be used for the analysis of one or two kinds of aldehydes and ketones. The absorbent solutions in these methods includes acidic sulfate, potassium hydroxide,water and weak acid. Because the reaction of these absorbent solutions and carbonyl compounds has no specificity, the selectivity and sensitivity of these methods are often low. Thus, the application of these methods in analysis of actual samples are limited greatly.

The Determination of T-2 Toxins by HPLC with Chemical Derivatization and Fluorescence Detection

Wenxiang HU, Qingtao PENG, Shenjian TAN, Jianshe WANG, Xunsheng SHAO, Peirang Chen, Ye CAO

1998, 19(S1):  407-408. 

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Even though many pharmaceuticals show native chromophoric properties, there are also many important compounds, such as anticholinergic drugs, toxins, steroids and anticancer agents, which are not chromophoric and can not be determined by usual spectra analysis. T-2 toxin is one kind of the compounds. The detection of these compounds by HPLC imposes severe limitation on sensitivity and ofen togather with unacceptable constraints on mobile phase selection. Precolumn or postcolumn derivatization technology by using chromophoric group is often an inexpensive but effective way to overcome this problem, which make these compounds chromophoric and then enhance detcetability of them. For trace analysis, there is a balance to be attained between rigour of sample cleanup and selectivity of detection. Derivatization of target compounds of pharmaceuticals interest offers significant advantages, such as improving selectivity and thus reducing the complexity of the sample cleanup required.

The Calculation for the Molecular Position Electronegativity of Organic Molecules

Han Chang-Ri

1998, 19(S1):  409-410. 

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The molecular position electronegativity (MPEN) is a new concept and based on the auther's studying of group electronegativity^[1,2]. MPEN represents the power of attracting an electron of the center atom situated different molecular environment. MPEN is defined as the electronegativity of the center atom situated different molecular environment and this is affectde by neighbors of the center atom.

A NEW METHOD FOR THE PREPARATION OF CARBONYL DIAZO COMPOUNDS

XueShun Jia, Lei SHI, DongLan Ma, YuLu WANG

1998, 19(S1):  411-412. 

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Azo compounds are very important in organic chemistry. In resent years, some notoworthy studies show that azobenzene derivatives possess very good optic remembering and photoelectric properties, optical switching and image storage by means of azobenzene liquid crystal film.^1,2 We have reported some new methods for the Azo compounds³. In this paper, We describe a new oxidation system KCIO₃/H₂SO₄ catalyzed by FeSO₄ to synthesis diazo compounds (ArN=NCON=NAr) in short time and good yield for the first time.

Stereochemistry of the Heterocyclic Alcohols Containing Piperidine Unit

Gao Shouhai, Hu Wenxiang, Yun Liuhong

1998, 19(S1):  413-414. 

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The stereochemistry of the heterocyclic alcohols (R₁-OH~R₄-OH,see Fig.1) containing piperidine unit has been studied on the basis of the calculations of molecular mechanics and quantum chemistry. The calculations of alcohols (R₁-OH~R₄-OH) and their carboxylate derivatives were carried out, and the results of these calculations were listed in Tab.1 and Tab.2. It was showed that there existed the non-classical orbital super-conjugated interactions between the nitrogen atom and oxygen atom which caused the conformations to be more stable when the hydroxylic group lay at axial than at equatorial with respect to the piperidine ring in compounds (R₁-OH) and (R₃-OH). If the axial hydrogen atoms at C₂ and C₆ positions in the piperidine ring were substituted, or the molecular existed in the polar solutions, this non-classical orbital super-conjugated interactions would be much weak even diminished. In this case,the conformations were more stable when the hydroxylic group at equatorial than at axial in these compounds. These consistented with the experimental results.

Structural characterization of a glucan from Angelica sinesis (Oliv) Diels

Chen Li, Cheng-Gang Huang, Zhi-Xiao Li, Yao-Zu Chen

1998, 19(S1):  415-415. 

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Angelica sinesis (Oliv) Diels is a traditional Chinese drug used clinically in the treatment of gynecological diseases. Its polysaccharide fraction been reported to have several immunomodulating, antitumor, antiradiation activities^[1] and a recent paper showed it could obviously act on the hemopoietic system^[2]. Haruki Y. et al. have elucidated the chemical structure of a α(1→4) linked D-glucan from Angelica acutiloba^[3]. We now describe the structure of a water soluble glucan, AS-1, which was isolated and purified from the water extract of Angelica sinesis (Oliv) Diels. It is only composed of D-glucose and its mean molecular weight is estimated to be 5.3×10⁵. The absorption peak of 846cm^-1 on IR, the chemical shift of δ 99.98 ppm for C-1,and the 168 Hz of ¹J_C-H suggested that the D-glucose residues were α-linked. Methylation analysis (Table 1),periodate oxidation, Smith degradation, ¹H NMR and ¹³C NMR (Table 2) showed that it is α(l→6) linked D-glucan to which are attached two glucosyl side chains, Glc-(l→3)-Glc→1 and Glc-(1→4)-Glc→1, both at 3-O of the glucosyl residues of every 14th glucose units of the main chain. The structure was further proved by using HMBC,HMQC and DQF-COSY techniques. The details of its pharmacological results will be published elsewhere.

Studies on Isothermal Vapor-Liquid Equilibrium for Styrene-Cumene Binary System

Yu Shuxian, Deng Fengjie, Xu Min, Yu Zubing, Han Shijun

1998, 19(S1):  416-417. 

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This dissertation has studied the isothermal vapor-liquid equilibrium(VLE) in associating system of styrene-cumene at 353.15K and 373.15K by using a modified Rose still. The pressures are indirectly measured from the boiling points of pure waler in a separate inclined cbulliometer with a pump-like stirrer. The experimental data are well correlated with Wilson equation.

Effect and Solvent Effect on Monooxygenation of Cyclohexane Catalyzed by A Dimanganese Schiff Base Complex

CHEN Xin-Bin, GUI Ming-De, ZHU Shen-Jie

1998, 19(S1):  418-419. 

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A new dimanganese Schiff base complex-Bis[N,N'-ethylene-2,2,-(phenylmethylene) bis (3,4-dimethyl pyrrole-5-aldimino)] dimanganese Mn₂L was synthesized and used as a catalyst for PhIO oxidizing cyclohexane to cyclohexanone and cyclohexanol. This paper reports temperature effect and solvent effect on the reaction.

Heterolytic and homolytic bond dissociation energies of the N-NO bonds in N-nitroso diethyl phosphoramidates

Kun Wang, Jinpei Cheng, Chongjie Zhu, Feng Gao

1998, 19(S1):  420-421. 

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Interest in nitric oxide(NO) as a biological radical in affecting human life has increased dramatically over the last twenty years.^[1] It has been implicated in diverse physiological process, including vasodilatory and antiplatelet effects, macrophage-induced cytotoxicity, and neurotransmission.

The First Titration Calorimetric Determination of Iron-Carbon Bond Dissociation Energy

Jiantao Guo, Jin-Pei Cheng

1998, 19(S1):  422-423. 

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Organometallic Chemistry is one of the most rapid growing areas in modern chemistry in the past a few decades. Interest in deepening a more fundamental understanding of the fabulous chemistries in this exciting area has led us to explore the information regarding to the M-C bonding energetics where M represents a metal atom, since breaking or forming a metal-carbon bond is an integral part of many key steps in organometallic reactions. Although scientists have a high desire for and have actually made considerable efforts determining metal-carbon bond strengths, the bond dissociation energy data of metal-carbon bond are still very scarce^[1-3].

Carbon-halogen Bond Cleavage Energies of Alkyl Halides and Haloalkyl Radical Anions in Solution

Lijuan Wang, Jinpei Cheng

1998, 19(S1):  424-425. 

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Radical anions are intermediates in a variety of processes:dissolving metal reductions, cathodic reductions⁽¹⁾,homogeneous redox reactions, S_RN² reactions⁽²⁾ and nucleophilic substitions⁽³⁾. Several techniques ranging from pulse rediolysis, near-infrared spectroscopy, derivative linear-sweep voltammetry, and electron spin resonance spectroscopy have been employed to study the characteristic properties of the radical anions. The most characteristic property for the radical anions derived from organic halides, in particular, has been known to be the severe weakening of the carbon-halogen bond and consequently the ease of its dissociative cleavage to form halide ion and radical (eq.l) or to form halogen atom and anion (eq.2) as seen in the key step of the S_RN¹ mechanism.

Metal Ions Transport across Liquid Organic Membranes by Cyclic Peptides

Linjing Mu, Jin-pei Cheng, Hai Huang, Ning Zhang, Jianming Lu, Xubo Hu

1998, 19(S1):  426-427. 

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Valinomycin is one of the most "important" antibiotic-ionophore. It is known to form more or less stable equimolar complexes with alkali ion in neutral solvents^[1] Some synthetic carriers showing similar properties have also become known, among them, the most frequently seen are compounds like depsipeptides, cyclic polyethers and polythioethers^[2]. These compounds are able to complex with alkali and alkaline-earth ions and make them soluble in nonpolar media. Such quality has attracted great research interest. In this note, we report our recent investigation on the migration of alkali and alkaline-earth metal ions across an organic phase as influence by cyclopeptides cyclo-(Pro-Gly)_3,4 synthesized in this laboratory.

Determination of N-NO Bond Heterolysis and Homolysis Energies of Nitrosoureas and Nitrosothioureas

Jin-Pei Cheng, Ming Xian, Xiaoqing Zhu, Yongkai Sun, Linjing Mu

1998, 19(S1):  428-429. 

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There is currently great interest in the chemistry of nitric oxide (NO) following many important discoveries showing that NO is involved in a range of human physiological processes.¹ Among ocean of researches in this area, some attention has been paid on the release of NO from aromatic N-nitrosoureas,not only from the point of view of their potential therapeutical use as alternative NO-releasing drugs,² but also with regard to their possible involvement in vivo as potential NO-storage and transport vehicles.³ Thus, the cytoxicity mediated by NO is expected to be potent in aromatic N-nitrosoureas having NO-releasing ability. For NO-donor compounds, homolytic cleavage energy of N-NO bond (ΔHhomo) is considered a good measure of their NO-releasing ability. Here, we provide a method to derive the ΔHhomo data and present some results showing structure influence on the N-NO bond strengthes for several series of disubstituted ureas and thioureas.

Cyclopeptides incorporating pyridine subunit as new receptors for phosphomonoester

Linjing Mu, Jinpei Cheng, Hai Huang, Xiaohu Gao, Jianming Lu

1998, 19(S1):  430-431. 

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Phosphates play a crucial role in a wide range of biological processes. Numerous efforts have been devoted to molecular recognition, transport and catalytic hydrolysis of phosphate^1-4. Recent reports have shown that molecules containing several hydrogen-bonding group directed into a cleft or cavity can effectively recognize phosphate^5,6. We now report a new family of pseudo-cyclopeptides 1-4 as receptors for phosphomonoester, which were synthesized by the reaction of pyridine 2,6-dicarbonyl dichloride with cystine bis-peptides(H₂N-Xaa-Cyst-Xaa-NH₂) dimethylester leading to a variety of 1+1 cystine-based cyclic peptides with the general structure cyclo(Py-CONH-Xaa-Cyst-Xaa-NHCO-) (Cyst=L-cystine dimethyl ester; Xaa=amino acid X) and identified by conventional spectroscopic methods⁷.

Characterization and Artificial Peroxidase Properties of Hemin Modified by β-Cyclodextrin

Han-xi SHEN, Lu-yuan MAO

1998, 19(S1):  442-443. 

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Biomimetic Enzyme Properties of Hemin Modified by β-Cyclodextrin in the Weak Alkaline Medium

Lu-yuan MAO, Han-xi SHEN

1998, 19(S1):  444-445. 

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Free radical telluroacylative addition of telluroesters to terminal alkynes

Chang-Qiu Zhao, Xian Huang, Jin-Liang Li, Ji-Ben Meng, Yong-Mei Wang

1998, 19(S1):  446-447. 

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Vinyl selenides and tellurides are important precursors of many kinds of organic compounds, particular the substituted alkenes that occurred in many biologically active compounds as skeleton structures. Thus the study of vinyl selenides and tellurides has attracted considerable attention in recent years. The bifunctional addition reactions involving selenium and tellurium moieties are the latest methods for preparation of vinyl selenides with various functional groups. Recently we have reported the selenocarbonylation of alkynes with selenoesters catalyzed by cuprous halides. Nevertheless the similar bifunctional addition involving tellurium atoms has not been reported. Considering the C-Te bonds are easier to be broken than corresponding C-Se bonds, the vinyl tellurides containing electron-withdrawing groups may have particular reactivity and application in the preparation of substituted alkenes. Herein we describe the synthesis of β-aryltelluro-α,β-unsaturated ketones via bifunctional addition.

Structural Analysis of Simvastatin

Zuo Yumin, Xu Jie, Ren Sumei

1998, 19(S1):  448-449. 

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Compactin(1) and lovastatin(2) are potent inhibitors of cholesterol biosynthesis in humans, and the more active semisynthetic derivative simvastatin(3) are pharmacologically useful compounds for lowering of serum cholesterol levels, The structure of simvastatin and related compounds is shown in Fig.1. It contains a hexahydronaphthalene ring system, a β-hydroxylactone and dimethylbutyrate structural unit.

New Method for Developing ALS Enzyme Inhibitor

LIU Jie, LI Zhengming

1998, 19(S1):  450-451. 

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Following with the rapid development of computer technology, Computer Aided Molecular Design (CAMD) has become a focus of attention in assisting the molecular design of some novel agrochemicals.

A Novel Nucleophilic Substitution of 3-Halo-6-phenoxypyridazines

Ren Kangtai, Li Huiying, Qi Jun, Song Honghai, Wang Xiang, Yang Huazheng

1998, 19(S1):  452-453. 

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Pyridazines have been found wide application in chemistry of pharmaceuticals and agrochemicals^[1,2], therefore methods of direct introduction of substituents into pyridazine ring are of great interest^[3]. Pyridazine belongs to highly electrophilic heterocycles, it shall undergo various nucleophilic substitution with X^-、O^-、S^-、C^- and H^- anions^[4].

Microwave Assisting Solid Phase Organic Reactions-Approach to the Efficient Solid Phase Organic Synthesis

YU Ai-Ming, YANG Hua-Zheng, ZHANG Chun-Xiang, LIU Zhun, ZHANG Zheng-Pu

1998, 19(S1):  454-455. 

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Solid phase organic synthesis provides a rapid mean for the preparation of compounds libraries, and has been successfully used for the construction of both oligometric compounds and small molecule compounds libraries^[1]. That leads the resurgence of interest in solid phase organic synthesis, which encourages organic chemists to develop new reliable reactions, linkers and analytical techniques.

An ab initio Research on the Pentacoordinate Carboxylic-phosphoric Anhydride

ZHONG Rugang, LI Zhao-Long, ZHAO Yu-Fen, DAI Qianhuan

1998, 19(S1):  460-461. 

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It is well known that phosphorylated peptides involve in a lot of biological processes, such as metabolism, membrane transportation, muscle contractility,cell cycle control, and so on^[1] Some recent researches revealed a new respect of this kind of compounds. An N-phosporyl-α-amino acid can react with an n-peptide to form an ¹(n+l)-peptide and react with an n-(desoxy-)ribotide to form an (n+1)-(desoxy-)ribotide in aqueous solution at about 38℃, as shown in Fig.1. However, N-phosporyl-β-amino acids can not react with the same substrates at the same conditional^[2].

A theoretical Research on Two Type Compouds Derived from 5λ⁵-phospha-spiro[4.4]nonane

ZHONG Rugang, LU Hai-Yan, ZHAO Yu-Fen, DAI Qianhuan

1998, 19(S1):  462-463. 

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Two kinds of derivatives of 5λ⁵-phospha-spiro[4.4]nonane, which are similar in structure, have very different properties. l,4,6-Trioxa-9-aza-5λ⁵-phospha-spiro[4.4]nonane-7-one (1) are easily hydrolyze in aqueous solution at room temperature as general pentacoordinate phosphorus compounds do. But the other derivative, l,6-Dioxa-4,9-diaza-5λ⁵-phospha-spiro[4.4]nonane-2,7-dione (2) are unusually stable in the same condition.

Synthesis and Molecular Recognition of Novel Cleft-type Receptors

Shu-hua Chen, Dong-Hong Li, Fang Li, Hua-Ming Zhao

1998, 19(S1):  466-467. 

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A novel type of molecular cleft has been designed and synthesized from estrogen and approprite spacer groups such as xylylene or pyridine dimethylene. These receptor compounds 1a-d and 2a-d have been characterized by Mass spectra,¹H-NMR spectra,IR spectra and elemental analyses. The structures of the receptors are shown in scheme 1. Their molecular recognition properties for the aromatic amine and aromatic amino acids have been investigated by UV-visble spectrophotometric titration. The titration data were analyzed by using the Benesi-Hildebrand equation^[1].

Synthesis of Calix[6]arene-Porphyrin Receptors and Study on their Catalytic Performance in Epoxidation of Styrene

Donghong Li, Shuhua Chen, Huaming Zhao

1998, 19(S1):  468-469. 

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The artificial receptors with multiple recognition site had been synthesized by linking two unsymmetrical monofunctionalized porphyrin to p-tert-butyl calix[6]-arene via two flexible chain, followed by inserting metal ion into the porphyrin species.The structures (see Fig 1) of these calix[6]arene-diporphyrins and their metal complexes were confirmed by UV-vis spectra, IR spectra, mass spectra, ¹NMR spectra(600 MHz) and/or ¹³C NMR. Their conformations were investigated preliminarily by UV-vis spectra and computer simulation. In constrast with the correspounding porphyrin monomer, the soret bond of calix[6]arene-diporphyrins in UV-vis spectra showed hypsochromic shift. This phenomenon suggested that two porphyrin rings maintain a face to face parallel conformation, as confirmed by computer simulation that showed the conformation energy is the lowest as two porphyrin rings hold such a conformation. Besides, simplicity of the ¹NMR spectra indicates that the conformation of calix[6]arene-diporphyrin possesses high symmetry. Therefore,the calix[6]arene must be cone conformation.

Hydrolysis of Lipophilic Amino Acid Esters Catalyzed by Metallomicelles

Xiao-Qi Yu, Jing Song You, Qing-Xiang Xiang, Qian-Shun Yan, Ru-Gang Xie

1998, 19(S1):  470-471. 

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Metallomicelles as the model of hydrolytic metalloenzymes have begun recently¹. Examples are the metal-ion complexes of lipophilic imidazoles² and pyridines³ co-micelled with surfactants. Herein we report the complexes of a novel macrocyclic 12-membered di-oxotetraamine ligand bearing bis-hydroxy groups as functional pendants which can mimic the catalytic function of carboxypeptidase A in micellar media.

The Competition between the S_RN1 and the S_NAr on the β-position of Porphyrin Ring

Chen Zhangping, Chen Yangsheng, Jiang Zhongxing, Zai Baoping, Wu Xuanjie

1998, 19(S1):  476-477. 

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In our recently reports, a series of amphipathic β-substituted porphyrins are synthesized, And their LB films show some novel properties.^[1] During the preparation of the intermediate of amphipathic porphyrins by the reaction of 2-nitro-5, 10,15,20-tetraphenylporphyrinato copper (Ⅱ) 1 with phenoxide ion 2(eq.l), we found that the product distribution mainly relied on if the electron acceptor was added and which solvent was used. Here we will first report the influence of p-dinitrobenzene (P-DNB) to the above reaction,the influence of the solvents to this reaction and the reaction of 2-naphoxide with 1 will be reported elsewhere.

Study on the Heterogeneous Photodegradation of 2,6-dimethylphenol on the Nanometer-size TiO₂ with UV-spectra and Fluorescent Spectra

MA Wan-Hoa, CAI Ru-Xiu

1998, 19(S1):  478-479. 

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In this paper, a verious of intermediates were found in photodegradiation of 2,6-dimethylphenol catalyzed on nanometer size TiO₂ surface by UV absorption spectra and fluorescent spectra.The characteristics of intermediates formed and degradiated contributed to traping had step by step in successive reaction, and possible mechanism was discussed.

Photosensitization of Two-dimensional Conjugated Polymers of Iron(Ⅱ)-and Cobalt(Ⅱ)-porphyrazine with Sulfur Bridges to CdS-PVA Film

PENG Zheng-he, CHEN Xiao-gui, WANG Zheng-ping, WEI Yi-hai, QIN zi-bin

1998, 19(S1):  480-481. 

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Metal-porphyrazines (MPzs) and their polymers exhibit high thermal stability and unique photoelectric functions due to the macrocyclic planar structure and a delocalized π-electron system of the porphyrazine^[1-3]. We have been found that the metal-thioporphyrazines (MS_xPzs) and their conjugated polymers (PMS_xPzs) have usually peculiar a gas-sensitivity, photosensitivity and electrocatalytic activity^[5-8]. In the present abstract we report briefly photosensitization of the title polymers PMS₈Pz (see Scheme 1) to the CdS-PVA film.

The Studies of Fast Atom Bombardment Mass Spectrometry of Melezitose Derivatives

Cao Linghua, Sun Guanzhong, Liu Yuting, Dou Hui, Wang Wei

1998, 19(S1):  482-483. 

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Melezitose is a kind of nonreducing sugar, its structure is 3-(α-D-glucopyranosyl)-β-D-fructofuranosyl-α-D-glucopyranose, it is a principal constituent of Alhagi pseudalhagi Desv.manna, which is used as a drug in Uygur medicine.

The photoconductive properties of bisazo pigments from 1,5-diaminoanthraquinone

Zhang Yu-Hong, Ruan Jian-Li, Lu Wen-Li, Yu Qing-Sen

1998, 19(S1):  484-485. 

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The photoconductive properties of azo compounds were reported as early as 1969 by Rau^[1] who observed photocurrents from thinlayers of 1-phenylazo naphthol. From then on, thousands of pigments of a variety structures have been synthesized and studied^[2].The pigments absorb and photorespond in the visible region are not usable in the xerographic printers which use the long wavelength illuminators, such as light-emitting diodes(660-700nm) and solid state diode lasers(700-850nm). So the need of laser addressable photoconductors is obvious and the various strcture IR photoconductors were studied intensely in recent years^[3-5].

Theoretical Studies of Azulene and Its Derivatives

Bo-Cheng Wang, Pei-Yu Wang

1998, 19(S1):  489-489. 

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The results of ab initio calculation with STO-3G and 6-31G basis set on the azulene and its derivatives (included azulenequinones, diazoazulenequinones and polyether bridged azulenes) are presented in accordance with considerations of structures and bonding. Azulene is a nonalternant aromatic compound with ten π electrons and it has either C_s or symmetry dgpend on the different carbon and carbon bonding. The calculation results indicate that C_s symmetry is the ground state structure of azulene. TTie simple MO and CIS calculations describe the excited state of azulene.

Electrooxidation of Azulene Compounds

Arh-Hwang Chen

1998, 19(S1):  490-490. 

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Azulenoid, a parent structure of bicyclo[5,3,0] decapentaene with 10 π-electrons, is a class of the fused bicyclic compounds, non-benzenoid hydrocarbons. It is essentially used for the dye materials, the medical treatment of inflammation and hypertension and the development of liquid crystals. More recently, azulopquinones have been found to exhibit a significant antitumor activity. In the early organic electrochemical studies, azulene was first known the oxidation potential, 0.91 V vs SCE in acetic acid. The reversible and irreversible reduction potential,-1.6 V and -2.6 V vs Ag/AgCl in liquid methyl amine and dimethyl amine, respectively, were measured by Heinze et al in 1989 using cyclovoltammetric method. The conducting polymers were successfully developed from azulene and 4,6,8-trimethylazulene via electropolymeriztion by Waltman et al in 1986. Recently in 1993, Shono et al revealed that azulene was easily reduced to 5,5'-biazulene or consequently to react with alkyl halides producing 1,1'-dialkyl-5,5'-biazulene.