1a,7b-dihydro-2,2-dimethyl-7b-(2-pyridyl)-2H-oxireno[c][1]benzopyran-6-carbonitrile → rac-cis-3,4-dihydro-3-hydroxy-2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran-6-carbonitrile

Participants

Reaction Steps

646 mg of 1a,7b-dihydro-2,2-dimethyl-7b-(2-pyridyl)-2H-oxireno[c][1]benzopyran-6-carbonitrile were dissolved in 100 ml of ethanol and 100 mg of 10% palladium-on-charcoal were added. The mixture was shaken under a hydrogen atmosphere overnight and then filtered. The filtrate was evaporated and the resulting oil was chromatographed twice on silica gel, with the elution being carried out initially using ethyl acetate/petroleum ether (1:3) and then 1% to 2% (v/v) methanol/dichloromethane. There were obtained 66 mg of rac-cis-3,4-dihydro-3-hydroxy-2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran-6-carbonitrile of melting point 186°-188° C. (from acetonitrile) and 340 mg of rac-trans-3,4-dihydro-3-hydroxy-2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran-6-carbonitrile of melting point 175°-176° C. (from t-butyl methyl ether).

Provenance & Evidence