反应详情

To a solution of the acetate from Step B (0.90 g, 1.84 mmol) in a mixture of tetrahydrofuran (20 mL) and ethanol (20 mL) was added sodium borohydride (70 mg, 1.84 mmol) and calcium chloride (0.21 g, 1.84 mmol) with stirring. The suspension was stirred at ambient temperature for 1 h and more sodium borohydride (70 mg, 1.84 mmol) was added. The reaction was monitored by TLC until no starting material remained. The volatiles were evaporated and the residue mixed with water and extracted with ethyl acetate (3×50 mL). The combined extracts were dried over magnesium sulfate, filtered and evaporated to dryness. Chromatography on silica eluting with a gradient of 20% to 50% EtOAc/hexane gave a solid (0.67 g, 82%): mp 97-99° C.; LCMS (+APCI) 448, 450 (M+H).

1. stirringThe suspension was stirred at ambient temperature for 1 h
2. customThe volatiles were evaporated
3. additionthe residue mixed with water
4. extractionextracted with ethyl acetate (3×50 mL)
5. dry with materialThe combined extracts were dried over magnesium sulfate
6. filtrationfiltered
7. customevaporated to dryness