反应详情

To a solution of the compound of Example 11 (0.8 g, 1.96 mmol) in methanol (10 mL) is added a solution of sodium hydroxide (0.392 g, 9.8 mmol) in water (5 mL) and the resultant mixture refluxed for 2 hr. The reaction is cooled to room temperature and the methanol is removed under reduced pressure on a rotary evaporator. The residual aqueous phase is washed with ether (2×10 mL), and then the pH of the aqueous phase is adjusted to 2-3 with 2N sulfuric acid and extracted with ethyl acetate (2×20 mL) to yield the title compound (0.6 g, 80%). MS m/z 395.1 (M+.+1); [α]D20=+141.09° (c=1, CH3OH).

1. customthe methanol is removed under reduced pressure on a rotary evaporator
2. washThe residual aqueous phase is washed with ether (2×10 mL)
3. extractionextracted with ethyl acetate (2×20 mL)