Sodium Hydroxide → 2-Hydroxy-3-methyl-4-oxo-4-(3',4'-dichlorophenyl)butanoic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a solution of 1-(3,4-dichlorophenyl)propanone (5.8 g, 28.5 mmol)in 95% ethanol (100 mL) a solution of glyoxylic acid monohydrate (2.63 g, 28.5 mmol) in water (20 mL) was added at 0° C., followed by dropwise addition of a solution of sodium hydroxide (4.6 g, 0.114 mol). The temperature during the addition was maintained below +5° C. on cooling. The resulting reaction mixture was stirred at 0° C. over 3 hours, then allowed to warm to room temperature and stirred further 12 hours. The most of ethanol was then removed under reduced pressure (15° C.), the residue was diluted with water and the pH of the obtained suspension adjusted to 2 by addition of 37% HCl, on stirring and cooling at 0° C. The aqueous phase was extracted with ethyl acetate, and the collected organic extracts were washed with brine, dried and evaporated to provide the crude reaction product as a light yellow oil (4.4 g). Column chromatography (SiO2; CH2Cl2/MeOH 95:5) provided the pure titled compound (2.1 g, 27%), colorless solid (Ethyl ether/hexane) mp. 103-104° C.;

Herkunft & Nachweise