Revised Structures,1-Methylene-1 H -[1,4]thiazino[4,3- a ]-benzimidazole and 10-Methylene-10 H -imidazo[2,1- c ][1,4]-benzothiazine Derivatives,for the Cycloadducts Accompanying Rearrangement from Imidazo[2,1- b ]benzothiazole and Thiazolo [3,2- a ] benzimidazole Derivatives with Propiolic Esters †

Abstract

Formerly-proposed structures, thiazolo[3,2-a] [1,5]benzodiazepine and [1,4]diazepino[7,1-b]benzothiazole derivatives, cycloadducts from the reactions of thiazolo[3,2-a] benzimidazole and imidazo[2,1-b]benzothiazole derivatives with propiolic esters, are revised to methyl 2-[4-methyl-(E)-1H-[1,4]thiazino[4,3-a]benzimidazol-1-ylidene)methoxycarbonylmethyl]-(E)-acrylate and methyl [2-methyl-(E)-10H-imidazo[2,1-c] [1,4]benzothiazine-10-ylidene)-methoxycarbonylmethyl]-(E)-acrylate, respectively, whose structures are deduced by X-ray structure analysis.