2-Anisidine hydrochloride → 3-(2-Methoxyphenylaminomethylene)tetrahydropyran-2-one

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Reaction Steps

The sodium salt of 3-(hydroxymethylene)-tetrahydropyran-2-one (25 g, 0.17 mol) and 2-methoxyaniline hydrochloride (32 g, 0.2 mol) in ethanol (750 ml) were warmed to 70° C. with stirring for 2 hours, then filtered hot. After evaporation of the ethanol, the crude product was taken up in dichloromethane, washed with dilute hydrochloric acid, dried and evaporated. Trituration with ether gave 3-(2-methoxyphenylaminomethylene)tetrahydropyran-2-one (21.5 g, 55%) as a mixture of E and Z isomers, m.p. 85°-100°.

Provenance & Evidence