反应详情

p-Toluenesulfonic acid (1.0 g) was added to a solution (50 ml) of Compound 45a (2.0 g) obtained in Step A of Example 45 in methanol at room temperature, followed by heating under reflux. The reaction solution was cooled and then the solvent was distilled off under reduced pressure. A saturated aqueous solution of sodium bicarbonate was added to the residue, followed by extraction with chloroform. The organic layer was washed with a saturated saline and dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (chloroform) to give Compound 57 (1.0 g, 48.2%) as a pale-yellow oily substance.

1. temperatureby heating
2. temperatureunder reflux
3. temperatureThe reaction solution was cooled
4. distillationthe solvent was distilled off under reduced pressure
5. additionA saturated aqueous solution of sodium bicarbonate was added to the residue
6. extractionfollowed by extraction with chloroform
7. washThe organic layer was washed with a saturated saline
8. dry with materialdried over anhydrous magnesium sulfate
9. distillationthe solvent was distilled off under reduced pressure
10. customThe residue was purified by silica gel column chromatography (chloroform)