反应详情

A mixture of 5-bromo-3-methylbenzo[b]thiophene-2-carboxylic acid (5.80 g.), ethanol (500 ml.) and concentrated sulphuric acid (2 ml.) was heated under reflux for 48 hours, and then evaporated. Dilute aqueous ammonia solution was added and the solid was filtered off, washed well with water and dried to give 5-bromo-3-methylbenzo[b]thiophene-2-carboxylic acid ethyl ester (5.70 g.), m.p. 87°-88° C., raised to 88°-89° on crystallization from petrol (b.p. 80°-100°).

1. temperaturewas heated
2. temperatureunder reflux for 48 hours
3. customevaporated
4. additionDilute aqueous ammonia solution was added
5. filtrationthe solid was filtered off
6. washwashed well with water
7. customdried