反应详情

Concentrated sulphuric acid (1 mL) was added to a solution of 2-amino-4-methyl-benzoic acid (1.0 g, 6.62 mmol) in dry methanol (10 mL) at 0° C., and then heated at reflux for 16 hr. The mixture was cooled to room temperature and concentrated in vacuo. The crude compound was diluted with water (25 mL) and basified with sodium bicarbonate (10 mL). The aqueous layer was extracted with ethyl acetate (2×50 mL) and the combined organic layers were washed with water (50 mL), brine (50 mL) and dried over sodium sulfate. The organic layer was concentrated under reduced pressure affording 2-amino-4-methyl-benzoic acid methyl ester (900 mg, 82%) as yellow liquid.

1. temperatureheated
2. temperatureat reflux for 16 hr
3. concentrationconcentrated in vacuo
4. additionThe crude compound was diluted with water (25 mL)
5. extractionThe aqueous layer was extracted with ethyl acetate (2×50 mL)
6. washthe combined organic layers were washed with water (50 mL), brine (50 mL)
7. dry with materialdried over sodium sulfate
8. concentrationThe organic layer was concentrated under reduced pressure