反应详情

Sodium cyanoborohydride (8.42 g, 134 mmol) was added into a stirred suspension of 5-aminophthalide (5.0 g, 33.5 mmol) and 37% CH2O/H2O solution (24.9 mL, 335 mmol) in 120 mL of acetonitrile. The mixture was stirred at room temperature for 1 hour, cooled to 0° C. and 120 mL of 10% aqueous acetic acid solution was added. The mixture was then stirred at room temperature for 1 hour, evaporated under low pressure until no acetonitrile remained. The resulting mixture was extracted with ethyl acetate (2×125 mL). The combined organic extracts were washed with saturated NaHCO3 solution (125 mL) and brine (125 mL), dried over Na2SO4 and evaporated to dryness to give a light brown solid, which was triturated with hot MeOH (10 mL) to give the title compound (3.9 g, 66%) as an off-white solid.

1. temperaturecooled to 0° C.
2. stirringThe mixture was then stirred at room temperature for 1 hour
3. customevaporated under low pressure until no acetonitrile
4. extractionThe resulting mixture was extracted with ethyl acetate (2×125 mL)
5. washThe combined organic extracts were washed with saturated NaHCO3 solution (125 mL) and brine (125 mL)
6. dry with materialdried over Na2SO4
7. customevaporated to dryness
8. customto give a light brown solid, which
9. customwas triturated with hot MeOH (10 mL)