Abstract: A simple synthesis of 3-amino-6/8-substituted-1H-pyrazolo[4,3-c]quinolines via closed ring reaction of 4-amino-3-aryl-5-mercapto-s-1,2,4-triazoles with 1,4-dihydro-4-oxo-quinoline-3-carboxylic acids in the presence of phosphoryl chloride, followed by the ring-opening reaction in the presence of hydrazine hydrate was described. This novel and straightforward method for the construction the 3-amino-1H-pyrazolo[4,3-c]quinolines can be carried out under mild conditions by using readily accessible or commercially available inexpensive materials. The new compounds were dertemined by elementary analyses, IR, ¹H NMR and MS spectra. Their spectral properities were also discussed. This mothod may represent a potentially useful route to otherwise laboriously accessible condensed pyrazoles ring systems. With the advantage of economy, a single pot procedure, excellent yields and mild conditions. This condensed pyrazoles can be synthesized on a large scale conveniently and economically.

Key words: 1,2,4-Triazolo[3,4-b]-1,3,4-thiadiazole, 3-Amino-6/8-substituted-1H-pyrazolo[4,3-c]quinoline, Synthesis, Property