Hydrochloric Acid → 4-Chlorobenzo(b)thiophene-2-carboxylic Acid

Participants

Reaction Conditions

Reaction Steps

A mixture of methyl 4-chlorobenzo[b]thiophene-2-carboxylate (20 g), 5M aqueous sodium hydroxide solution (100 ml) and water (300 ml) was heated at 95° C. for 5 hours then poured into a mixture of concentrated hydrochloric acid (180 ml) and water (2000 ml) and stirred at ambient temperature for 2 hours. The resulting solid was collected by filtration, washed with water (3×500 ml), and dried in vacuo at 60° C. to give 4-chlorobenzo[b]thiophene-2-carboxylic acid (21.0 g) as an off-white solid, m.p. 246-248° C.

Provenance & Evidence