title: Examination of chiral stability during the preparation of hydrazides and coupling by the azide procedure using a series of model peptides.
abstract: The peptide hydrazides of N-benzyloxycarbonylglycyl-X where X = alanine, leucine, phenylalanine, valine and isoleucine have been prepared by hydrazinolysis of the corresponding methyl esters and 2,4-distributed-5 (4H)-oxazolones, and by the carbodiimide-mediated reactions of the peptide acids with hydrazine in the presence of 1-hydroxybenzotriazole. The stereochemical purity of the products was examined by coupling them by the azide method with an ester of lysine followed by analysis for the diastereomeric tripeptides by an established procedure. The results concur with and substantiate the generally held notions on the chiral stability associated with hydrazinolysis and the azide procedure, except that an optically pure hydrazide could not be obtained from the oxazolone of the alanyl peptide.
mesh_terms: D001386:Azides; D055598:Chemical Phenomena; D002621:Chemistry; D004151:Dipeptides / Q000138:chemical synthesis*; D004355:Drug Stability; D006834:Hydrazines; D007202:Indicators and Reagents; D008722:Methods; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D001386:Azides; D004151:Dipeptides; D006834:Hydrazines; D007202:Indicators and Reagents