反应详情

A mixture of 48 (1.2 g, 3 mmol), 2,5-dimethoxybenzyl amine (0.6 g, 3.3 mmol) camphor sulfonic acid (45 mg) in toluene (15 ml) was heated at reflux with removal of water for 3 hours and then the solvent was removed. The residue was dissolved in small amount of THF (3 ml) and this solution was added to a solution of sodium triacetoxyborohydride (1.7 g, 8 mmol) in acetic acid (40 ml) at room temperature. The mixture was stirred at room temperature for 3 hours and the solvent was removed. Water was added and the mixture was neutralized with NaHCO3 and extracted with EtOAc three times. The combined extracts were dried over Na2SO4 and concentrated. Recrystallization from MeOH/acetone to give by-product. The mother liquor was concentrated and the residue was purified by recrystallization from MeOH/EtOAc to give 50 (0.27 g, 0.56 mmol, 19%)

1. temperaturewas heated
2. customthe solvent was removed
3. dissolutionThe residue was dissolved in small amount of THF (3 ml)
4. customthe solvent was removed
5. additionWater was added
6. extractionextracted with EtOAc three times
7. dry with materialThe combined extracts were dried over Na2SO4
8. concentrationconcentrated
9. customRecrystallization from MeOH/acetone
10. customto give by-product
11. concentrationThe mother liquor was concentrated
12. customthe residue was purified by recrystallization from MeOH/EtOAc