Water → 6-cyano-3,4-dihydro-2,2-dimethyl-trans-3-hydroxy-4-(4-methoxy-2-oxo-3-pyrrolin-1-yl)-2H-1-benzopyran

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Reaction Steps

A solution of 6-cyano-3,4-dihydro-2,2-dimethyl-3,4-epoxy-2H-1-benzopyran (15 g) and 4-methoxy-3-pyrrolin-2-one (8.5 g) in dimethylsulfoxide (40 ml) was stirred and sodium hydride (80% dispersion in oil, 2.2 g) was added. The mixture was stirred at room temperature for 5 hours. Water (50 ml) was slowly added, and the resulting solution extracted with ethyl acetate (2×50 ml). After drying the organic layer with sodium sulfate the solvent was removed under reduced pressure and the residual oil chromatographed on silica gel (4% methanol in methylene chloride). The product obtained was dissolved in diethylether and precipitated with pentane to afford 4 g of 6-cyano-3,4-dihydro-2,2-dimethyl-trans-3-hydroxy-4-(4-methoxy-2-oxo-3-pyrrolin-1-yl)-2H-1-benzopyran, m.p. 256° C.

Provenance & Evidence