Synthesis and in vitro antimicrobial activity of some newer quinazolinone–sulfonamide linked hybrid heterocyclic entities derived from glycine

Abstract

A novel series of 4-(amino or acetamido)-N-{[3-(substituted aryl)-4-oxo-3,4-dihydroquinazolin-2-yl]-methyl}benzenesulfonamide derivatives (1–19) were designed to assimilate 4-quinazolone and sulfonamide moieties in a single molecular framework. To derive entitled hybrid entities with structural diversity, an efficient multi-step synthetic approach initiated from glycine was developed, which involves milder conditions for emphasizing steps viz., reaction in aqueous-media, phosphazo-method of condensation, base mediated selective ester-cleavage, along with key-step, rapid and improved Grimmel’s hetero-cyclization method. The structure of the synthesized compounds was confirmed by physico-chemical characteristics and spectroscopic investigations. All these compounds were screened for their in vitro antimicrobial activity. The minimum inhibitory concentrations of the synthesized compounds against various bacteria (S. aureus, B. cereus, E. coli, K. pneumonia, P. aeruginosa) and fungus (A. niger, C. albicans) was measured by broth microdilution assay. Further, results on the preliminary biological activity indicated that most of the screened compounds have displayed varied degree of inhibitory actions.