Antimicrobial Activities of some Synthesized Cyclo (Nα-dinicotinoyl) [L-phenylalanyl-L-leucine] Pentapeptide Candidates

Abstract

Some of cyclo (N^α-di-nicotinoyl)[L-phenylalanyl-L-leucine]pentapeptides3-6 has been synthesized starting from bis-(1-carboxy-2-substituted)-3,5-diaminocarbonyl)pyridine 3 and N,N-bis-(1-hydrazonyl-2-substituted)-3,5 diaminocarbonyl) pyridine 2. Treatment of 1 or 2 afforded the corresponding bis-ester derivative 3, which was hydrolyzed with sodium hydroxideto give bis-acid 4. Cyclization of bis-acid 4 with L-dibasic amino acid methyl esters, afforded the corresponding macrocyclic methyl esters 5a,b, respectively. Finally, hydrazonolysis of 5a,b with hydrazine hydrated in refluxing methanol afforded macrocyclic pentapeptide hydrazides 6a,b, respectively. Some of these compounds exhibited antimicrobial activities comparable with Chloramphenicol and Fusidic acid as reference drugs.