反应详情

To a solution of 21-2 (1.38 g, 4.50 mmol) in THF (22.5 ml) cooled in an ice-bath was added 1N lithium hydroxide solution (22.5 ml). The resulting solution was stirred 18 h while warming to ambient temperature. The solution was partially evaporated at reduced pressure, and the remaining aqueous solution was washed with ethyl acetate (20 ml). The aqueous layer was cooled in an ice-bath, stirred rapidly, and concentrated hydrochloric acid (2 ml) was added dropwise, resulting in formation of a precipitate. The mixture was stirred 1 h, the precipitate was collected and dried in vacuo to give product 21-3 as a white solid, mp: 200°-202° C.

1. customThe solution was partially evaporated at reduced pressure
2. washthe remaining aqueous solution was washed with ethyl acetate (20 ml)
3. temperatureThe aqueous layer was cooled in an ice-bath
4. stirringstirred rapidly
5. additionconcentrated hydrochloric acid (2 ml) was added dropwise
6. customresulting in formation of a precipitate
7. stirringThe mixture was stirred 1 h
8. customthe precipitate was collected
9. customdried in vacuo