Sulfuric Acid → [2-Cyano-2-(3,4-dimethoxy-phenyl)-vinyl]-carbamic acid ethyl ester

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Reaction Steps

To the mixture of 2-(3,4-Dimethoxy-phenyl)-3-oxo-propionitrile (20.5 g, 0.1 mol), urethane (8.9 g, 0.1 mol) in toluene (400 mL) was added concentrated sulfuric acid (0.5 mL, 10 mmol). The mixture was refluxed and was concentrated by slow distillation to a volume to about 50 mL. The cooled mixture was filtered and the precipitate was washed with benzene and dried. Flash chromatography (Merck Silica gel 60, 70–230 mesh, 20% methylenechloride) afforded [2-Cyano-2-(3,4-dimethoxy-phenyl)-vinyl]-carbamic acid ethyl ester as a solid: LC-MS m/e calcd for C14H16N2O4 (MH+) 277, found 277. 1H NMR (300 MHz) compatible.

Provenance & Evidence