Ethyl cyanoacetate → 2-Cyano-3-(3,4-dichlorophenyl)-but-2-enoic acid ethyl ester

関与物質

反応手順

A mixture of 3′,4′-dichloroacetophenone (50 mmol), ethyl cyanoacetate (50 mmol), acetic acid (1.14 mL) ammonium acetate (400 mg), and benzene (50 mL) was heated to reflux in a Dean-Stark apparatus. After approximately 10 hours, additional ethyl cyanoacetate (50 mmol), acetic acid (1.14 mL), and ammonium acetate (400 mg) are added. After an additional 10 hours, the reaction was cooled to room temperature, diluted with ethyl acetate (30 mL), washed with water (240 mL), brine (40 mL), and dried (Na2SO4). After filtering, the extract was concentrated in vacuo and the desired product, as a 1:1 mixture of E and Z-isomers, was isolated by column chromatography on silica gel, eluting with 5% ethyl acetate in petroleum ether. The purified oil solidified on standing at room temperature. Yield: 60%.

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