Synthesis and antimicrobial evaluation of novel bis-β-lactam grafted macrocycles.

A series of macrocyclic bis-β-lactams has been synthesized in three good yielding steps using a Staudinger [2+2] cycloaddition reaction of ketene derived from phenoxyacetyl chloride as the key step. The reaction provided a diastereomeric mixture of cis-anti-cis (C2-symmetry) and cis-syn-cis (meso) bis-β-lactam grafted macrocycles which were screened for their in vitro antibacterial and antifungal activities against four human pathogenic bacteria and two pathogenic fungi. Compounds 6a and 6b exhibited antibacterial activity at lower concentration against four bacterial pathogens and compounds 10b and 12a showed antifungal activity against two fungal pathogens when compared to reference control.