反应详情

313 mg of methyl 3,4-dihydro-2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran-6-carboxylate were dissolved in 10 ml of dichloromethane at room temperature and 283 mg of m-chloroperbenzoic acid were added. After stirring at room temperature for 2 hours the mixture was washed with sodium bisulphite solution and sodium bicarbonate solution. The organic phase was dried over sodium sulphate and evaporated. The residue was chromatographed on silica gel using initially 2% (v/v) methanol/ethyl acetate and finally 5% (v/v) methanol/ethyl acetate for the elution. There were obtained 250 mg of 2-[3,4-dihydro-6-(methoxycarbonyl)-2,2-dimethyl-2H-1-benzopyran-4-yl]pyridine N-oxide as an oil which solidified upon trituration with diethyl ether. After recrystallization from toluene the product melted at 128°-130° C.

1. washwas washed with sodium bisulphite solution and sodium bicarbonate solution
2. dry with materialThe organic phase was dried over sodium sulphate
3. customevaporated
4. customThe residue was chromatographed on silica gel using initially 2% (v/v) methanol/ethyl acetate and finally 5% (v/v) methanol/ethyl acetate for the elution