反应详情

A mixture of 47 (3.9 g, 10 mmol), 2,5-dimethoxybenzyl amine (1.9 g, 11 mmol) camphor sulfonic acid (120 mg) in toluene (40 ml) was heated at reflux with removal of water for 8 hours and then the solvent was removed. The residue was dissolved in small amount of THF (5 ml) and this solution was added to a solution of sodium triacetoxyborohydride (5.3 g, 25 mmol) in acetic acid (100 ml) at room temperature. The mixture was stirred at room temperature for 4 hours and the solvent was removed. Water (25 ml) was added and the mixture was neutralized with sodium bicarbonate (NaHCO3) and extracted with ethyl acetate (EtOAc) three times. The combined extracts were dried over sodium sulfate (Na2SO4) and concentrated. The crude was purified by recrystallization from EtOAc to give 49 (2.4 g, 4.4 mmol, 44%)

1. temperaturewas heated
2. customthe solvent was removed
3. dissolutionThe residue was dissolved in small amount of THF (5 ml)
4. customthe solvent was removed
5. additionWater (25 ml) was added
6. extractionextracted with ethyl acetate (EtOAc) three times
7. dry with materialThe combined extracts were dried over sodium sulfate (Na2SO4)
8. concentrationconcentrated
9. customThe crude was purified by recrystallization from EtOAc