Carbon Dioxide → 18781-38-9

Participants

Reaction Steps

A mixture of 6-bromo-3-methylbenzo[b]thiophene (16.8 g) and methyl iodide (23.8 g) was added dropwise to a stirred mixture of dry ether (150 ml) and magnesium (11.06 g) at such a rate that gentle reflux was maintained. When the addition was complete, the mixture was heated under reflux with stirring for 30 minutes, then cooled and poured onto a mixture of crushed solid carbon dioxide and ether. When all the carbon dioxide had evaporated, 2N hydrochloric acid (100 ml) was added and the mixture was shaken. The ether layer was separated and the aqueous layer was extracted with ether. The ether solutions were combined, dried (Na2SO4) and evaporated to give a solid which was crystallized from ethyl acetate to give 3-methylbenzo[b]thiophene-6-carboxylic acid (7.71 g), m.p. 230°-232° C.

Provenance & Evidence