m-Chloroperbenzoic acid → 2,2-Dimethyl-4-(1-oxidopyridin-1-ium-2-yl)-3,4-dihydrochromene-6-carbonitrile

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Reaction Steps

406 mg of m-chloroperbenzoic acid were added to a solution of 528 mg of 3,4-dihydro-2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran-6-carbonitrile in 15 ml of dichloromethane at room temperature. After 2 hours at room temperature, the mixture was washed with sodium bicarbonate solution and the organic phase was dried over sodium sulphate and evaporated. The residue was crystallized from t-butyl methyl ether and was recrystallized from toluene to give 360 mg of 2-(6-cyano-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)pyridine N-oxide of melting point 158°-160° C.

Provenance & Evidence