K. Kobayashi, K. Yoneda, M. Uchida
Dec 1, 2001
Citations
0
Influential Citations
7
Citations
Journal
ChemInform
Abstract
4,7-Dioxo-4,7-dihydrobenzo[b]thiophene-2-carboxylates (4) have been synthesized in a one-pot procedure from 2-acyl-1,4-benzoquinones (1) and mercaptoacetates (2) by using 1-trimethylsilylimidazole as a protective reagent as well as a base. Thus, reaction of 1 with 2 in THF at room temperature was followed by treatment with excess of l -trimethylsilylimidazole at 80 °C. Then the cooled mixture was hydrolyzed with hydrochloric acid and oxidized with cerium(IV) ammonium nitrate (CAN) to give the expected thiophenequinone derivatives (4). 4,9-Dioxo-4,9-dihydronaphtho[2,3-b]thiophene-2-carboxylates (7) were similarly prepared from 2-acyl-1,4-naphthoquinones (5) and mercaptoacetates, in general, by omitting the CAN oxidation procedure.