反应详情

The starting material is prepared as follows: To the mixture of 31.5 g of carbon tetrabromide and 65 ml of methylene chloride the solution of 50.0 g of triphenylphosphine in 175 ml of methylene chloride is added dropwise while stirring at 0°-5° under nitrogen. After 20 minutes the solution of 13.5 g of 4-benzyloxy-3,5-dimethoxybenzaldehyde in 50 ml of methylene chloride is added dropwise and the mixture stirred at room temperature for 2 hours. It is washed with 200 ml of water, dried and evaporated. The residue is extracted with hexane-diethyl ether (5:1), the extract evaporated, the residue chromatographed on silica gel, eluted with diethyl ether, the eluate evaporated and the residue recrystallized from hexane, to yield the β,β-dibromo-4-benzyloxy-3,5-dimethoxy-styrene melting at 76°-77°.

1. customThe starting material is prepared
2. additionis added dropwise
3. stirringthe mixture stirred at room temperature for 2 hours
4. washIt is washed with 200 ml of water
5. customdried
6. customevaporated
7. extractionThe residue is extracted with hexane-diethyl ether (5:1)
8. customthe extract evaporated
9. customthe residue chromatographed on silica gel
10. washeluted with diethyl ether
11. customthe eluate evaporated
12. customthe residue recrystallized from hexane