Bromine → Ethyl 5-bromo-4,5,6,7-tetrahydro-3-methylthio-4-oxobenzo[c]thiophene-1-carboxylate

Participants

Reaction Steps

Ethyl 4,5,6,7-tetrahydro-3-methylthio-4-oxobenzo[c]thiophene-1-carboxylate (25.12 g) was dissolved in chloroform (400 ml); a solution of bromine (15.59 g) in chloroform (20 ml) was added dropwise at room temperature over a period of 30 minutes. After the reaction mixture was stirred at room temperature for 40 minutes, it was washed with a 2% aqueous solution of sodium sulfite (400 ml), water, a saturated aqueous solution of sodium hydrogen carbonate and water in that order, and dried (MgSO4), after which the solvent was distilled off to yield ethyl 5-bromo-4,5,6,7-tetrahydro-3-methylthio-4-oxobenzo[c]thiophene-1-carboxylate (28.27 g, 87.1%), which was then recrystallized from ethyl acetate-hexane. Light-yellow prisms. Melting point 147-148° C.

Provenance & Evidence