Pyridine → (2E)-3-ethoxy-N-(4-trifluoromethylphenyl)prop-2-enamide

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Reaction Steps

To a solution of 4-(trifluoromethyl)aniline (2.56 g, 15.9 mmol) in dichloromethane (40 ml) was added pyridine (3.77 g, 47.7 mmol). The solution was cooled to 0° C. before a solution of 3,3-diethoxypropanoyl chloride (4 g, crude) in dichloromethane (10 ml) was added dropwise with stirring. The resulting solution was stirred for 4 hours at 20° C. and then washed with water (200 ml). The resulting mixture was extracted with dichloromethane (3×80 ml) and the organic layers were combined and concentrated under vacuum. The crude residue was purified by Pre-TLC with 1-20% ethyl acetate in petroleum ether to elute. The product-containing fractions were combined and concentrated under vacuum to afford (2E)-3-ethoxy-N-(4-trifluoromethylphenyl)prop-2-enamide as a yellow solid (4.0 g). (ES, m/z): [M+H]+ 260; 1H NMR (300 MHz, DMSO): δ 10.10 (s, 1H), 7.83 (d, J=8.4 Hz, 2H), 7.72 (s, 1H), 7.60 (d, J=8.7 Hz, 1H), 7.50-7.56 (m, 1H), 5.52 (d, J=12.4 Hz, 1H), 3.90-4.01 (m, 2H), 1.15-1.30 (m, 3H).

Provenance & Evidence