反应详情

To a solution of 5-hydroxy-4-methoxy-2-nitrobenzoic acid [Sinha J. Ind. Chem. Soc., 47, 925 (1970)] (83.0 g, 0.39 mol) in MeOH (250 ml) was added concentrated H2SO4 (20 ml) and the reaction mixture was heated to reflux for 16 h. On cooling, the reaction mixture was poured into aqueous potassium carbonate solution and acetic acid was added until pH 4 was reached. The mixture was extracted with chloroform, the organic layer washed twice with H2O and dried over MgSO4. Evaporation under reduced pressure afforded the subtitle compound as yellow crystals (77.0 g, 87%). Rf 0.30 (benzene/acetone 4/1, v/v); m.p. 146-9° C.

1. temperaturethe reaction mixture was heated
2. temperatureto reflux for 16 h
3. temperatureOn cooling
4. additionwas added until pH 4
5. extractionThe mixture was extracted with chloroform
6. washthe organic layer washed twice with H2O
7. dry with materialdried over MgSO4
8. customEvaporation under reduced pressure