Journal of Chemistry and Biochemistry December 2016, Vol. 4, No. 2, pp. 45-59 ISSN 2374-2712 (Print) 2374-2720 (Online) Copyright © The Author(s). 2015. All Rights Reserved. Published by American Research Institute for Policy Development DOI: 10.15640/jcb.v4n2a5 URL: https://doi.org/10.15640/jcb.v4n2a5 Synthesis of Some Novel Derivatives of Substituted 2H-[1]- Benzopyran-2-Ones and Their Antimicrobial Activity Ramiz HOTI 1 , Naser Troni 2 *, Idriz VEHAPI 3 , GJyle MULLIQI-OSMANI 4 , Hamit ISMAILI 5 & Veprim THAÇI 6 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-(N- benzylidene-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. Keywords: Benzopyran-2-one; benzaldehyde condensation; cyclization; antibacterial activity 1 Faculty of Nature Sciences, Department of Chemistry, University of Prishtina, “Mother Teresa” street, 10000 Prishtina, Kosovo. 2 Faculty of Nature Sciences, Department of Chemistry, University of Prishtina, “Mother Teresa” street, 10000 Prishtina, Kosovo. E-mail: naser_troni@ yahoo.com; ramizhoti@ yahoo.com; Phone: + 381 (0)38 249 872; Fax: +381 (0)38 226 104 3 Faculty of Nature Sciences, Department of Biology, University of Prishtina, “Mother Teresa” street, 10000 Prishtina, Kosovo. 4 Institute of Public Health of Kosovo,“Rrethi i Spitalit” street, 10000 Prishtina, Kosovo 5 Faculty of Nature Sciences, Department of Chemistry, University of Prishtina, “Mother Teresa” street, 10000 Prishtina, Kosovo. 6 Faculty of Nature Sciences, Department of Chemistry, University of Prishtina, “Mother Teresa” street, 10000 Prishtina, Kosovo.