反应详情

The compound (126 g) obtained in step B was dissolved in a mixed solvent of dichloromethane (150 ml) and ethanol (150 ml). A 4N hydrochloric acid-dioxane solution (500 ml) was added with stirring at room temperature and the mixture was stirred at the same temperature for 5 hr. The reaction mixture was diluted with dichloromethane and water and the aqueous layer was extracted. An ice-cooled aqueous sodium hydroxide solution was added to the ice-cooled aqueous layer to give a strongly-alkaline aqueous layer. The aqueous layer was extracted with dichloromethane. The organic layer was dried over potassium carbonate, and the insoluble material was filtered off. The solvent was evaporated under reduced pressure. The obtained oil was dissolved in diethyl ether (500 ml), and 4N hydrochloric acid-dioxane solution (140 ml) was added with stirring under ice-cooling to allow precipitation of a solid. This was filtered, washed with diethyl ether, and dried under reduced pressure to give the title compound (75.89 g, yield 81%) as a gray solid.

1. stirringthe mixture was stirred at the same temperature for 5 hr
2. extractionthe aqueous layer was extracted
3. temperatureAn ice-cooled aqueous sodium hydroxide solution
4. additionwas added to the ice-
5. temperaturecooled aqueous layer
6. customto give a strongly-alkaline aqueous layer
7. extractionThe aqueous layer was extracted with dichloromethane
8. dry with materialThe organic layer was dried over potassium carbonate
9. filtrationthe insoluble material was filtered off
10. customThe solvent was evaporated under reduced pressure
11. dissolutionThe obtained oil was dissolved in diethyl ether (500 ml)
12. addition4N hydrochloric acid-dioxane solution (140 ml) was added
13. stirringwith stirring under ice-
14. temperaturecooling
15. customprecipitation of a solid
16. filtrationThis was filtered
17. washwashed with diethyl ether
18. customdried under reduced pressure