反应详情

温度

-78 °C

N-butyllithium (232 mL, 464 mmol) was added slowly to a solution of tert-butyl (3,4-dimethoxyphenyl)carbamate (50 g, 193 mmol) in Tetrahydrofuran (THF) (500 mL) under N2 at −20° C. After being stirred for 2 h at −10° C. to −20° C., the mixture was cooled to −78° C. and diluted with Tetrahydrofuran (THF) (500 mL), followed by addition of solid carbon dioxide. The mixture was allowed to warm up to r.t. and was then partitioned between water and Et2O. The aqueous layer was acidified with 6N HCl to pH 1-2 and extracted with Et2O. The organic layer was separated, dried over Na2SO4 and evaporated. The crude product was purified by recrystallization from i-Pr2O to afford 6-((tert-butoxycarbonyl)amino)-2,3-dimethoxybenzoic acid (27.9 g, 94 mmol, 48.5% yield) as a white solid. LCMS: (M+H)+: 319.9.

1. temperatureto warm up to r.t.
2. customwas then partitioned between water and Et2O
3. extractionextracted with Et2O
4. customThe organic layer was separated
5. dry with materialdried over Na2SO4
6. customevaporated
7. customThe crude product was purified by recrystallization from i-Pr2O