反应详情

12 98 g of 4-[1,1-dimethyl-3-(2-pyridyl)-2-propynyloxy]benzonitrile were dissolved in 50 ml of 1,2-dichlorobenzene and heated at reflux for 5 hours. After cooling the mixture was evaporated. The residue was chromatographed on silica gel using ethyl acetate/petroleum ether (1:2), ethyl acetate/petroleum ether (1:1) and ethyl acetate for the elution. There were obtained 6.5 g of 2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran-6-carbonitrile of melting point 106-108° C. after recrystallization from cyclohexane.

1. temperatureheated
2. temperatureat reflux for 5 hours
3. temperatureAfter cooling the mixture
4. customwas evaporated
5. customThe residue was chromatographed on silica gel
6. washfor the elution