反应详情

7.0 g of the compound prepared under (b) are heated under reflux for 8 hours with a mixture of 50 ml of glacial acetic acid/hydrobromic acid (48% strength) in the volume ratio 1:1. After removing the acid in a rotary evaporator, the residue is taken up with methylene chloride/dilute ammonia, and the organic phase is dried and evaporated in a rotary evaporator. The oily residue is chromatographed on silica gel using a mixture of methylene chloride/ethyl acetate in the ratio 19:1. 2.2 g of pale yellow crystals (38% of theory) are obtained, melting point: 122°-123°.

1. temperatureare heated
2. customAfter removing the acid
3. customin a rotary evaporator
4. customthe organic phase is dried
5. customevaporated in a rotary evaporator
6. customThe oily residue is chromatographed on silica gel using
7. additiona mixture of methylene chloride/ethyl acetate in the ratio 19:1