反应详情

9 g of benzyl 2-[3-(4-cyanophenoxy)-3-methyl-1-butyn-1-yl]pyridine-5-carboxylate were dissolved in 300 ml of 1,2-dichlorobenzene and the solution was added dropwise over a period of 5 hours to 100 ml of 1,2-dichlorobenzene heated at reflux. After a further 2 hours the mixture was allowed to cool to room temperature and was then evaporated. The residue was chromatographed on silica gel using ethyl acetate/petroleum ether (1:9), (1:6) and (1:4) for the elution. There were obtained 5.5 g of benzyl 6-(6 -cyano-2,2-dimethyl-2H-1-benzopyran-4-yl)-3-pyridinecarboxylate which was used without further purification.

1. temperatureheated
2. temperatureat reflux
3. customwas then evaporated
4. customThe residue was chromatographed on silica gel
5. washfor the elution