TFAA mediated one-pot synthesis of chiral N-protected amino acid-derived 1,2,4-oxadiazoles and their antibacterial studies†

A scalable and environment-friendly one-pot two-component synthesis of chiral N-protected amino acid substituted 1,2,4-oxadiazoles from hydroxyl amidine and (S)-2-(2,2,2-trifluoroacetamido)propanoic 2,2,2-trifluoroacetic anhydride is described. This operationally simple methodology affords an efficient and convenient solution to synthesize chiral N-protected amino acids under catalyst-free conditions. All the synthesized compounds were screened for their in vitro antibacterial activity towards six human pathogenic bacterial species, among which, exhibited a significant efficacy against Escherichia coli with the MIC value of 0.19 μg mL⁻¹.