反应详情

To a solution of 2-amino-3-hydroxy-5-methylbenzoic acid hydrobromide (2.65 g, 10.7 mmol) in anhydrous CH3OH (50 mL) was added thionyl chloride (3.9 mL, 53.4 mmol) at −78° C. The resulting reaction mixture was allowed to warm to room temperature and then heated to reflux for 17 h. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. The residue was treated with a saturated aqueous NaHCO3 solution to adjust pH to 7 and then extracted with EtOAc (4×100 mL). The combined organic phase was washed with H2O, brine, dried (Na2SO4), filtered and concentrated under reduced pressure to afford methyl 2-amino-3-hydroxy-5-methylbenzoate (1.40 g, 72%): 1H NMR consistent.

1. customThe resulting reaction mixture
2. temperatureheated
3. temperatureto reflux for 17 h
4. temperatureThe reaction mixture was cooled to room temperature
5. concentrationconcentrated under reduced pressure
6. additionThe residue was treated with a saturated aqueous NaHCO3 solution
7. extractionextracted with EtOAc (4×100 mL)
8. washThe combined organic phase was washed with H2O, brine
9. dry with materialdried (Na2SO4)
10. filtrationfiltered
11. concentrationconcentrated under reduced pressure