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 o 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 o 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