反应详情

To a solution of 3-hydroxy-4-nitrobenzoic acid (50.0 g, 0.273 mol) in dichloroethane (1000 mL) under a nitrogen atmosphere were added trimethoxyborane (45.4 g, 0.437 mol) and boron trifluoride diethyl etherate (62.0 g, 0.437 mol) followed by dropwise addition of borane-pyridine complex (38.1 g, 0.410 mol). After stirring at room temperature for 4 hours, methanol (100 mL) was added dropwise under cooling in an ice-bath. The mixture was concentrated under reduced pressure and toluene (400 mL) was added to the residue. The resulting mixture was extracted with aqueous 1N NaOH solution (300 mL×3), and the combined aqueous lavers were acidified with conc. hydrochloric acid to pH 1 and extracted with ethyl acetate (500 mL and 300 mL). The organic layers were combined, washed with water (300 mL×2) and brine successively aid dried over magnesium sulfate, and the solvent was evaporated under reduced pressure to give B-3 (43.3 g, 94%).

1. additionfollowed by dropwise addition of borane-pyridine complex (38.1 g, 0.410 mol)
2. temperatureunder cooling in an ice-bath
3. concentrationThe mixture was concentrated under reduced pressure and toluene (400 mL)
4. additionwas added to the residue
5. extractionThe resulting mixture was extracted with aqueous 1N NaOH solution (300 mL×3)
6. extractionextracted with ethyl acetate (500 mL and 300 mL)
7. washwashed with water (300 mL×2) and brine successively aid
8. dry with materialdried over magnesium sulfate
9. customthe solvent was evaporated under reduced pressure
10. customto give B-3 (43.3 g, 94%)