A new aspect of the Pfitzinger reaction: Microwave-assisted synthesis of the new heterocyclic ring system 6-Arylbenzo[4,5]imidazolo[2,1-b]quino[4,3-e]-1, 3-thiazin-14-one

Abstract

We report herein on the utility of the Pfitzinger reaction in a facile two-step synthesis of the new heterocyclic ring system 6-arylbenzo[4,5] imidazolo[2,1-b]quino[4,3-e]-1,3-thiazin-14-one using microwave irradiation (MWI) and/or conventional heating. Microwave irradiation was used for a rapid and efficient synthesis of quinoline-4-carboxylic acids 6a - d from the reaction of isatin with 2-(1Hbenzimidazol-2-ylthio)-1-arylethanones 3a - d. Cyclization of cinchoninic acids 6a - d afforded the fused title compounds 7a - d. © 2009 Verlag der Zeitschrift für Naturforschung.