Abstract The synthesis of methyl 4, 7-dihydro-4, 7-dioxobenzo [b] thiophene-2-carboxylate (20) based on the reaction of methyl mercaptoacetate with activated 1, 4-benzoquinones is described. Methyl 4, 7-dihydro-4, 7-dioxo-5-hydroxybenzo [b] thiophene-2-carboxylate (24) and its corresponding methyl ether 26 were obtained through a Thiele-Winter acetoxylation on 20. On the basis of the properties of methyl 4, 7-dihydro-4, 7-dioxo-6-methoxy-benzo [b ...