反应详情

220 cc of thionyl chloride were progressively added to 50 gm of 4-methyl-thiophene-2-carboxylic acid [prepared by process in Beil, Vol. 18, p. 294] and the mixture was heated to reflux for 1 hour. Excess thionyl chloride was evaporated off under reduced pressure and the residue was distilled under reduced pressure to obtain 51 gm of 4-methyl-thiophene-2-carboxylic acid chloride boiling at 112°-114° C. at 18 mm Hg. which was used as is for the next step. The light yellow liquid was soluble in ether.

1. temperaturethe mixture was heated
2. temperatureto reflux for 1 hour
3. customExcess thionyl chloride was evaporated off under reduced pressure
4. distillationthe residue was distilled under reduced pressure