Hydrochloric Acid → (2E)-4-(3,4-Dimethoxyphenyl)-4-oxo-2-butenoic acid

Participants

Reaction Conditions

Reaction Steps

Into a 500 ml four-neck flask were charged 66.9 g (0.682 mol) of maleic anhydride, 150 ml of chlorobenzene, 71.6 ml (0.546 mol) of diethyl sulfate, and 0.186 g (0.975 mmol) of copper iodide under a nitrogen atmosphere. Then, the whole was cooled to 10° C. or lower and 67.6 g (0.507 mol) of aluminum chloride was added thereto. While temperature was maintained at 10 to 15° C., 25 ml (0.195 mol) of 1,2-dimethoxybenzene was added dropwise, followed by 2 hours of reaction. After termination of the reaction was confirmed by HPLC analysis, the reaction solution was added dropwise to 200 ml of a 1N hydrochloric acid aqueous solution cooled to 0° C. to decompose excess aluminum chloride. After liquid separation, the organic layer was washed with 200 ml of a 10% sodium bicarbonate aqueous solution to remove excess maleic anhydride. Then, 42.9 g (0.286 mol) of sodium iodide and 31.1 g (0.286 mol) of chlorotrimethylsilane were added to the organic layer, followed by heating and refluxing. After completion of the reaction, the organic layer was washed with 100 ml of a 5% sodium thiosulfate aqueous solution and 100 ml of a saturated sodium hydrogen carbonate aqueous solution to extract (E)-4-(3,4-dimethoxyphenyl)-4-oxo-2-butenoic acid into the aqueous layer, followed by adjusting the aqueous layer to pH 2.0. After 24 h of stirring at 5° C., filtration was conducted to obtain 24.9 g (yield 54.2%) of the aimed compound as light yellow crystals. As a result of HPLC analysis, the purity was found to be 98.5%.

Provenance & Evidence