关键词: 促黑激素; 促黄体素释放激素; 强腓肽; 甲酸铵催化转移氢化; 硝基还原

Abstract:

The p-aminophenylalanine was a useful functional amino acid in the design of peptide drugs, and it was usually prepared by the reduction of p-nitrophenylalanine. Ammonium formate catalytic transfer hydrogenation(AF-CTH) was confirmed feasible in transforming the aromatic nitro group into the amino group in a dipeptide, and the orthogonal protection for p-aminophenylalanine in traditional route could be avoided in this method. Therefore, we wondered if this method could be widely used for the reduction of p-nitrophenylalanine residue in various peptides, such as the MSH(tetrapeptide), LHRH(decapeptide) and dynorphin(heptadecapeptide) analogues. The reduction processes were monitored by HPLC and the results showed that all sequences could be smoothly transformed into the desired products, except the LHRH analogue containing p-chlorophenylalanine due to the dechlorination. It suggested that AF-CTH was an effective method for the reduction of the nitro group in a peptide. In addition, it was found that the reduction rate of the nitro group was slower in longer peptide and not obviously correlative to its site in peptide.

Key words: Melanocyte-stimulating hormones(MSH); Luteinizing hormone-releasing hormone(LHRH); Dynorphin; Ammonium formate catalytic transfer hydrogenation; Nitro group reduction