反应详情

温度

-78 °C

To a solution of the compound from Step A (0.87 g, 0.9 mmol) in dichloromethane (30 mL) at −78° C. was added boron trichloride (1M in dichloromethane, 9.0 mL, 9.0 mmol) dropwise. The mixture was stirred at −78° C. for 2.5 h, then at −30° C. to −20° C. for 3 h. The reaction was quenched by addition of methanol/dichloromethane (1:1) (9 mL) and the resulting mixture stirred at −15° C. for 30 min., then neutralized with aqueous ammonia at 0° C. and stirred at rt for 15 min. The solid was filtered and washed with CH2Cl2/MeOH (1/1, 50 mL). The combined filtrate was evaporated, and the residue was purified on a silica gel column (5×5 cm) using CH2Cl2 and CH2Cl2/MeOH (40/1 and 30/1) gradient as the eluent to furnish the desired compound (0.22 g) as a colorless foam.

1. waitat −30° C. to −20° C. for 3 h
2. customThe reaction was quenched by addition of methanol/dichloromethane (1:1) (9 mL)
3. stirringthe resulting mixture stirred at −15° C. for 30 min.
4. customneutralized with aqueous ammonia at 0° C.
5. stirringstirred at rt for 15 min
6. filtrationThe solid was filtered
7. washwashed with CH2Cl2/MeOH (1/1, 50 mL)
8. customThe combined filtrate was evaporated
9. customthe residue was purified on a silica gel column (5×5 cm)