Synthesis of Some Novel Derivatives of Substituted 2H-[1]- Benzopyran-2-Ones and Their Antimicrobial Activity

Abstract

Novel derivatives of substituted bezopyran-2-ones are synthesized by catalytic reactions under refluxing conditions. 4-Hydrazinyl-3-nitrobenzopyran-2-one 4 is synthesized from 4-hydroxybenzopyran-2-one 1 via three steps reaction. By condensation reaction of 4-hydrazinyl-3-nitrobenzopyran-2-one 4 and aromatic aldehydes, corresponding 4-(Nbenzylidene-hydrazino)-3-nitrobenzopyran-2-ones 5(a-c) are obtained. Cyclization reaction of 4-hydroxybenzopyran-2-one 1 with aromatic aldehydes and malononitrile, in the presence of SDS, resulted by formation of 2-amino-5-oxo-4-phenyl-(4H, 5H) pyrano-[3,2-c]-chromen-3-carbonitrile derivatives 6(a-c), whereas by reacting of 4-hydroxybenzopyran-2-one 1 and aromatic aldehydes, in presence of SDS, corresponding 3,3'-(benzylidene)-bis-4-hydroxyibenzopyran-2-ones 7(a-c) are synthesized. The synthesized products are characterized on the basis of spectrometric data. Antimicrobial activity of products 5(a-c), 6(a-c) and 7(a-c) against S. aurous, E. coli and Klebsiella are investigated measuring of inhibition zones around the discs which are marked with their N, N-DMF solutions. Compounds of series 5 and 6 showed considerable antimicrobial activity against these microorganisms, whereas compounds of series 7 showed moderate activity. Impact of the substituents in antimicrobial activity also is investigated.