Diels-alder reactions with cyclic sulfones: X. Synthesis of 4-carbamoyl- and 4-hydrazido-substituted hexahydro-1-benzothiophene S,S-dioxides

Abstract

Reactions of spiro[1-benzothiophene-4,5′-[1,3]dioxane]-4′,6′-diones with various amines led to the formation of 4-carbamoylhexahydrobenzo[b]thiophene-4-carboxylic acid 1,1-dioxides or their decarboxylation products, depending on the conditions. Hydrazinolysis of the spiro adducts in DMF gave the corresponding monohydrazides. The structure of 4-carbamoyl-7-methyl-5-phenyl-2,3,3a,4,5,6-hexahydro-1-benzothiophene-4-carboxylic acid 1,1-dioxide was proved by X-ray analysis.