反应详情

A solution of chromium trioxide (0.04 g, 0.4 mmoles) in water (0.15 ml) and acetic acid (0.3 ml) was added dropwise to a solution of (25R)-16β-hydroxy-26-phthalimidocholesterol (4) (0.26 g, 0.49 mmoles), and sodium acetate (1.00 g, 12.19 mmoles) in acetic acid (35 ml), and stirred for 18 hours at room temperature. The excess reagent was then destroyed with methanol (15 ml), and solvent was evaporated under reduced pressure. The resulting residue was diluted with water, and extracted with methylene chloride. The organic layer was washed with 5% K2CO3 and water, dried over sodium sulfate, and evaporated under reduced pressure to yield 0.23 g (89%) of (25R)-16-oxo-26-phthalimidocholesterol (5). The product was recrystallized from acetone and was found to have a melting point of 178°-180° C. Elemental and structural 1H-NMR) analyses of the product are described below.

1. customThe excess reagent was then destroyed with methanol (15 ml), and solvent
2. customwas evaporated under reduced pressure
3. additionThe resulting residue was diluted with water
4. extractionextracted with methylene chloride
5. washThe organic layer was washed with 5% K2CO3 and water
6. dry with materialdried over sodium sulfate
7. customevaporated under reduced pressure