反应详情

79 mg of 4-(4-chloro-2-pyridyl)-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-6-carbonitrile were dissolved in 10 ml of dichloromethane and 70 mg of m-chloroperbenzoic acid were added. The mixture was stirred at room temperature for 3 days, then washed in succession with sodium bisulphite solution, sodium bicarbonate solution and water, dried over sodium sulphate and evaporated. The residue was chromatographed on silica gel using 1% (v/v) methanol/ethyl acetate for the elution to give, after trituration with diethyl ether, a solid which was recrystallized from ethyl acetate/petroleum ether. There being obtained 20 mg of 4-chloro-2-(6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)pyridine N-oxide of melting point 173°-174° C.

1. washwashed in succession with sodium bisulphite solution, sodium bicarbonate solution and water
2. dry with materialdried over sodium sulphate
3. customevaporated
4. customThe residue was chromatographed on silica gel using 1% (v/v) methanol/ethyl acetate for the elution
5. customto give
6. customafter trituration with diethyl ether, a solid which was recrystallized from ethyl acetate/petroleum ether