Preparation of New Nitrogen-Bridged Heterocycles. 35. Smooth Synthesis of 10aH-Pyrido[1,2-d][1,4]thiazepine Derivatives

Abstract

Abstract Various 1-pyridinio(thiocarbonyl)methylides and 2-isoquinolinio(thiocarbonyl)methylides react smoothly with dimethyl acetylenedicarboxylate at room temperature or at the reflux temperature in chloroform to give new heterocycles, dimethyl 10aH-pyrido[1,2-d][1,4]thiazepine-1,2-dicarboxylate derivatives, in moderate yields. Similarly, the reactions of some 3-(1-pyridinio)thiophene-2-thiolates with the same reagent afforded the corresponding dimethyl 6aH-pyrido[1,2-d]thieno[2′,3′-b][1,4]thiazepine-5,6-dicarboxylates. The structures of these 1,4-thiazepine derivatives were mainly assigned based on physical and spectral inspections, and were finally confirmed by X-ray analyses of three compounds.