反应详情

A solution of ammonium cerium nitrate (125 g; 228 mmol) in water (320 ml) was added to a solution of Example 28 (42 g crude; 95 mmol) in ethyl acetate (90 ml) and the mixture was stirred overnight. The aqueous phase was extracted three times with ethyl acetate, then rendered alkaline with NaHCO3 and extracted again with ethyl acetate. The combined organic phases were washed with 5% strength NaHCO3 solution and saturated sodium chloride solution, dried and concentrated. Silica gel chromatography of the residue (hexane/ethyl acetate step gradient) gave 19.2 g of a yellow solid [72% of theory; m.p. 80°-5° C.; Rf : 0.54 (methylene chloride: methanol=10:1)].

1. extractionThe aqueous phase was extracted three times with ethyl acetate
2. extractionextracted again with ethyl acetate
3. washThe combined organic phases were washed with 5% strength NaHCO3 solution and saturated sodium chloride solution
4. customdried
5. concentrationconcentrated