反应详情

Mixture of p-toluene-sulfonic acid monohydrate (0.38 g, 2.0 mmol, 0.2 equiv), compound 22 (4.0 g crude, ˜9.88 mmol, 1.0 equiv) and toluene (100 mL) was refluxed for 1 hour. After cooling to room temperature, the mixture was washed sequentially with saturated sodium bicarbonate (100 mL) and saturated brine (100 mL). The organic layer was dried over sodium sulfate, filtered, and concentrated under reduced pressure. The residue was purified on an AnaLogix (25-80 g) column, eluting with a gradient of 0 to 10% ethyl acetate in heptanes to give compound 23 (2.5 g, 67% yield for 2 steps) as a white solid.

1. temperaturewas refluxed for 1 hour
2. washthe mixture was washed sequentially with saturated sodium bicarbonate (100 mL) and saturated brine (100 mL)
3. dry with materialThe organic layer was dried over sodium sulfate
4. filtrationfiltered
5. concentrationconcentrated under reduced pressure
6. customThe residue was purified on an AnaLogix (25-80 g) column
7. washeluting with a gradient of 0 to 10% ethyl acetate in heptanes