反应详情

A mixture of 3,5-dimethyl-4-methoxybenzoic acid ethyl ester (PREPARATION 2, 10.5 g) and aqueous sodium hydroxide (20%, 100 ml) is refluxed for 18 hours. The solution is cooled and acidified with hydrochloric acid (12N, pH 2). The acidified solution is extracted with chloroform (3×). The combined extracts are dried over sodium sulfate and concentrated under reduced pressure to give a solid which is recrystallized from ether/pet ether mixture to give the title compound, mp 189°-191°.

1. temperatureis refluxed for 18 hours
2. temperatureThe solution is cooled
3. extractionThe acidified solution is extracted with chloroform (3×)
4. dry with materialThe combined extracts are dried over sodium sulfate
5. concentrationconcentrated under reduced pressure
6. customto give a solid which
7. customis recrystallized from ether/pet ether mixture