Azirine-containing dipeptides and depsipeptides: synthesis, transformations and antibacterial activity.

Azirine-containing dipeptides and depsipeptides with a wide range of substituents have been synthesized in high yields via the Passerini and Ugi multicomponent reactions (MCRs) using 2H-azirine-2-carboxylic acids as the acid component. The obtained MCR adducts have been transformed to lactam-fused aziridines, as well as pyrrole, imidazole, aziridine, and other derivatives, containing the dipeptide or depsipeptide moiety. The azirine-containing depsipeptides exhibit antibacterial activity against the ESKAPE pathogens, especially Gram-positive bacterial strains (E. faecium - MIC 16 μg mL-1, S. aureus - MIC 9 μg mL-1).