Pyrrole-Annulated Heterocyclic Systems. Synthesis of 2H-Pyrrolo[3,4-b][1,5]benzothiazepine 4,4-Dioxide Derivatives

Abstract

Condensation of 2-nitrothiophenol with ethyl propiolate afforded 3-(2-nitrophenylthio)propenoate. Oxidation of sulfur atom to sulfone group gave ethyl 3-(2-nitrophenylsulfonyl)propenoate, which underwent condensation with tosyl methylisocyanide (TosMIC) to yield ethyl 4-(2-nitrophenylsulfonyl)pyrrole-3-carboxylate. Reduction of nitro group afforded ethyl 4-(2-aminophenylsulfonyl)-1H-pyrrole-3-carboxylate, which was cyclized to 2H-pyrrolo[3,4-b][1,5] benzothiazepin-10(9H)-one 4,4-dioxide. Similar procedure was used for the synthesis of 9,10-dihydro-10-methyl-2H-pyrrolo[3,4-b][1,5]benzothiazepine 4,4-dioxide.