Some new [(chromen-4-ylamino)-ethyl]-azetidin-2-ones and their antibacterial activity

Abstract

A series of new azetidin-2-ones, on the basis of 3-nitrobenzopyran-2-one were synthesized by cyclo-condensation of various Schiff bases of coumarin with acetyl chloride. 4-(2-Amino-ethylamino)-3-nitro-chromen-2-one (3) is synthesized by condensation of 4-chloro-3-nitrobenzopyran-2-one (2) and ethane-1,2-diamine. The catalytic condensation of compound 3 with benzaldehyde, salicylaldehyde or 3-nitrobenzaldehyde yielded corresponding 4-[4-(benzylidene-amino)-phenylamino]-3-nitrobenzopyran-2-ones, 4a-c. The cyclization reac-tion of compounds 4a-c with acetyl chloride yielded corresponding substituted azetidin-2-ones, 5a-c. The structures of the obtained compounds were established by FT-IR and NMR spectrometric data and their elemental analysis. Prepared compounds 4a-c and 5a-c were screened for their antibacterial activity against S. aureus, E. coli and Klebsiella by disc diffusion method. Compounds 4a-c exhibited moderate antibacterial activity, whereas compounds 5a-c displayed significant activity against these microorganisms. The impact of substitutions in antimicrobial activity was also explored.