反应详情

620 mg of the crude product obtained in Example 28 was dissolved in 10 ml of methylene chloride, and to the solution were sequentially added 0.29 ml of benzyloxycarbonyl chloride and 3.04 ml of triethylamine with ice cooling. After stirring for two hours with ice cooling, 40 ml of saturated sodium chloride aqueous solution was added to the reaction mixture, which was then extracted twice with 20 ml of chloroform, and the extract was dried over magnesium sulfate and concentrated under a reduced pressure to obtain a residue. The residue was dissolved in 6 ml of methanol, and after the addition of 2 ml of 1N sodium hydroxide aqueous solution, the mixture was refluxed for two hours, dried over magnesium sulfate and concentrated under a reduced pressure. The resulting residue was applied to a silica gel column and eluted with chloroform/methanol (80:1 to 50:1) to obtain 336 mg of the title compound as colorless crystals.

1. additionwas added to the reaction mixture, which
2. extractionwas then extracted twice with 20 ml of chloroform
3. dry with materialthe extract was dried over magnesium sulfate
4. concentrationconcentrated under a reduced pressure
5. customto obtain a residue
6. temperaturethe mixture was refluxed for two hours
7. dry with materialdried over magnesium sulfate
8. concentrationconcentrated under a reduced pressure
9. washeluted with chloroform/methanol (80:1 to 50:1)