Substituted Quinolinones, Part 12: Heterocyclization Reactions of 3-(3-Chromonyl)acryloylquinolinone with Some Bifunctional Nucleophiles Mohamed Abass, Mohamed Abdel-Megid, and Mohamed Hassan Department of Chemistry, Faculty of Education, Ain Shams University, Roxy, Heliopolis, Cairo, Egypt Abstract: 4-Hydroxy-1-methyl-3-[E-3-(4-oxo-4H-chromen-3-yl)acryloyl]quinolin- 2(1H )-one (3) was smoothly obtained via a one-pot aldol dehydration reaction of 3-acetyl-4-hydroxyquinolin-2(1H )-one with 3-formylchromone and was utilized to prepare miscellaneous triheterocyclic systems containing the quinolinone moiety. Both the a,b-unsaturated ketone side chain and the g-pyrone ring in compound 3 were subjected to nucleophilic cyclization with certain 1,2- and 1,3-bifunctional N,N-, N,O-, N,C-, and O,C-nucleophiles under different reaction conditions. Many pyr- azolinyl-, isoxazolinyl-, pyrimidinyl-, and pyridinylquinolinones bearing other six- or five-membered heterocyclic systems have been conveniently synthesized using more than one synthetic route. Keywords: chromone, nucleophilic cycloaddition, quinolinone, a,b-unsaturated ketone INTRODUCTION Quinolinones are the effective moiety in a large number of natural and synthetic heterocyclic compounds that exhibit significant antibiotic activity Received in the U.K. April 27, 2006 Dedicated to the memory of the late Professor Sayed Ibrahim El-Nagdi. Address correspondence to Mohamed Abass, Department of Chemistry, Faculty of Education, Ain Shams University, Roxy, Heliopolis 11757, Cairo, Egypt. E-mail: m.abass@chemist.com Synthetic Communications w , 37: 329–352, 2007 Copyright # Taylor & Francis Group, LLC ISSN 0039-7911 print/1532-2432 online DOI: 10.1080/00397910601033930 329