Synthesis of chiral linear and macrocyclic candidates: III. Synthesis and antimicrobial activity of linear tetrapeptide and macrocyclic pentapeptide Schiff bases

A series of tetrapeptide Schiff bases and a macrocyclic pentapeptide were synthesized using Nα-dinicotinoyl-bis[L-leucyl-L-phenylalaninyl acid hydrazide] derivative and macrocyclic pentapeptide ester as starting materials and were screened for antimicrobial activity. Some of the newly synthesized compounds exhibited better antimicrobial effect compared to the reference controls. The structures of the newly synthesized compounds were confirmed by IR, NMR, and mass spectral data and elemental analyses.