反应详情

200 mg of the product of Stage C of Example 3 were dissolved in 5 ml of dimethyl ether of ethylene glycol and 1 ml of concentrated sulfuric acid was added at ambient temperature. After stirring for one hour, water was added while cooling in an ice bath. Extraction was carried out with dichloromethane and the organic phases .were washed and dried. The solvent was evaporated under reduced pressure to obtain 180 mg of crude product which was crystallized from ethyl acetate to obtain 140 mg of the expected product melting at 130°-132° C.

1. additionwas added at ambient temperature
2. temperaturewhile cooling in an ice bath
3. extractionExtraction
4. washthe organic phases .were washed
5. customdried
6. customThe solvent was evaporated under reduced pressure
7. customto obtain 180 mg of crude product which
8. customwas crystallized from ethyl acetate