反应详情

580 mg of 4-[1,1-dimethyl-3-(2-pyrimidinyl)-2-pro pynyloxy]benzonitrile were heated at reflux for 3 hours in 20 ml of dichlorobenzene. The solution was allowed to cool and was then evaporated to dryness. The residue was chromatographed on silica gel using ethyl acetate/petroleum ether (1:2) and subsequently ethyl acetate/petroleum ether (1:1) for the elution. There was obtained 361 mg of 2,2-dimethyl-4-(2-pyrimidinyl)-2H-1-benzopyran-6-carbonitrile which melted at 108°-109.5° C. after recrystallization from tert-butyl methyl ether.

1. temperatureto cool
2. customwas then evaporated to dryness
3. customThe residue was chromatographed on silica gel
4. washfor the elution