4-Methoxybenzaldehyde → (Z)-3-(4-methoxyphenyl)-2-methyl-prop-2-enoic acid

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Reaction Conditions

Reaction Steps

A mixture of 68 g of p-anisaldehyde (500 mmol), 81 g of propionic anhydride (625 mmol) and 48 g of sodium propionate (500 mmol, dried for 5 h at 120° C.) is heated under argon for 30 h at 140° C. This solution, cooled to 80° C., is poured slowly into 400 ml of vigorously stirred saturated aqueous sodium hydrogen carbonate solution. After extraction with dichloromethane (twice 300 ml), the organic phases are combined and then washed with saturated sodium hydrogen carbonate solution (twice 150 ml). The aqueous phases are combined and then poured slowly into a mixture of 300 ml of 12N hydrochloric acid solution and 100 g of crushed ice. The precipitate is collected after filtration, dried in a dessicator, triturated in twice 150 ml of petroleum ether, filtered again and dried in the dessicator. 55.70 g (290 mmol) of a white solid are collected. Yield=58% m.p. 178°-182° C. IR (nujol): 1665 cm-1 1H NMR (CDCl3 /TMS): 9.20 to 8.90 (broad s, 1H); 7.60 (s, 1H); 7.35 to 6.90) AB, 4H, J=8 Hz); 3.80 (s, 3H); 2.1 (s, 3H) 13C NMR (CDCl3): 170.40; 158.50, 137.60; 130.90; 128.10; 126.30; 113.50; 54.80.

Provenance & Evidence