Ethyl 3-oxo-4-phenylbutanoate

Light-yellow Liquid.

Ethyl 3-oxo-4-phenylbutanoate is a useful synthetic intermediate. It is used to prepare pyrazolone derivatives as antiprion compounds. It is also used to prepare pyrrolinylaminopyrimidine analogs as inhibitors of AP-1 and NF-κB mediated gene expression.

Journal of Medicinal Chemistry, 44, p. 78, 2001 DOI: 10.1021/jm001034k
Chemical and Pharmaceutical Bulletin, 30, p. 2440, 1982 DOI: 10.1248/cpb.30.2440

The synthesis of Ethyl 3-oxo-4-phenylbutanoate is as follows:Monoethyl monopotassium malonate (12.9 g, 2.3 equivalents) was mixed with tetrahydrofuran (200 ml), and the mixture was cooled to 5°C. Triethylamine (8.2 g, 2.5 equivalents) and magnesium chloride (8.62 g, 2.8 equivalents) were added, and the mixture was stirred at 5 to 20°C for 3 hours. The reaction mixture was cooled to 5°C. Phenacyl chloride (5 g, 32 mmol, 1 equivalent) was gradually added, and the mixture was stirred at 5 to 20°C for 63 hours. The mixture was cooled to 5°C, and 1 N hydrochloric acid (30 ml) was added. Tetrahydrofuran was evaporated away under reduced pressure, and extraction was carried out with ethyl acetate (50 ml). The organic layer was washed with 1 N hydrochloric acid (30 ml), water (10 ml), saturated aqueous solution of sodium hydrogencarbonate (30 ml) and water (10 ml) in order. The solvent was evaporated away under reduced pressure to obtain the Ethyl 3-oxo-4-phenylbutanoate as a pale yellow oil (5.82 g, yield: 86 %).