The preparation of some thiochroman-3-ones and derivatives

Abstract

The use of 2,3-dihydrobenzo[b]thiophene-2,3-dione as a source of 2-mercaptophenylacetic acid permits a convenient preparation of 2-carboxymethylthiophenylacetic acid or derivatives. These undergo a Dieckmann cyclization to 3-acetoxybenzothiopyrans, which may be hydrolysed to thiochroman-3-ones. The further reactions of some of these are described.