A convenient approach to the synthesis of ω-heterocyclic amino acids from carboxy lactams through ring-chain transformation; part 1: Synthesis of (2S)-/(2R)-2-amino-4-(1-aryl-/1,5-diaryl-1H-pyrazol-3-yl)butyric acid

Abstract

A general method is reported for the synthesis of ω-heterocyclic α-amino acids, which involves preparation of enaminone intermediates from thiolactams, followed by reaction with dinucleophiles, resulting in a single-step condensation and ring-chain transformation to the desired ω-heterocyclic α-amino acids after deprotection of amine and carboxylic group. The reaction steps preserve the chirality of the parent-substituted lactam. The method is illustrated by the synthesis of (2S)- and (2R)-2-amino-4-(1-aryl-/1,5-diaryl-1H-pyrazol-3-yl) butyric acids.