Studies on Hydroxy Amino Acids. IV. Syntheses of Several Peptides Containing Aziridinecarboxylic Acid Derived from the Corresponding Hydroxy Amino Acid Derivatives

The β-elimination reaction of the O-tosyl β-hiydroxy amino acid peptide derivative was thoroughly investigated. The N-tosyl-l-serylglycine ester and the N-tosyl-l-threonylglycine ester gave the N-tosyl-l-aziridinecarbonyl-glycine ester and the N-tosyl-3-methyl-l-aziridinecarbonylglycine ester as the resulting products respectively by the elimination reaction. On the other hand, the N-carbobenzoxyglycyl-l-serylglycine ester was not converted into the aziridine peptide derivative; only the dehydroalanine peptide was obtained. However, the N-tosyl-l-phenylalanyl-l-threonylglycine ester and the N-carbobenzoxyglycyl-l-threonylglycine ester were converted into the corresponding aziridine peptide, and the N-tosyl-l-phenylalanyl-3-methyl-l-aziridinecarbonylglycine ester and the N-carbobenzoxyglycyl-3-methyl-l-aziridinecarbonylglycine ester were obtained respectively. It was concluded that the peptides containing threonine were easily converted into the aziridine peptides and not the serine peptides by the β-elimination reaction.