Hydrochloric Acid → HCID 23050231, compound

Participants

Reaction Steps

4-Chloro-5,6-dimethoxy-benzo[b]thiophene-2-carboxylic acid ethyl ester (29.5 g) was suspended in a mixture of methanol (450 ml), water (75 ml) and potassium carbonate (20.4 g) under an atmosphere of nitrogen. The reaction mixture was heated at reflux for 1 hour then cooled and poured into water (2.5 liter) containing hydrochloric acid (5M, 60 ml). The resultant white solid was filtered and dried at 65° C. under vacuum to give 4-chloro-5,6-dimethoxy-benzo[b]thiophene-2-carboxylic acid (26.8 g). A portion crystallised from dichloromethane:methanol had, m.p. 267°-270° C.

Provenance & Evidence