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4-(3-BROMO-PHENYL)-3-OXO-BUTYRIC ACID ETHYL ESTER synthesis

7synthesis methods
-

Yield:866270-04-4 100%

Reaction Conditions:

Stage #1: ethyl potassium malonatewith triethylamine;magnesium chloride in acetonitrile; for 3 h;
Stage #2: 3-Bromophenylacetic acidwith 1,1'-carbonyldiimidazole in acetonitrile at 18 - 25; for 18.5 h;Heating / reflux;

Steps:

87; 256

4-(3-Brornophenyi)-3-oxo-butyric acid ethyl ester (Scheme 7, A); EPO To a stirring suspension of potassium malonate (7.42 g, 43.6 mmol) in anhydrous acetonitrile (100 mL) at ambient temperature was added triethylamine (9.0 mL, 64.4 mmol) and magnesium chloride (4.94 g, 51.9 mmol) under an argon atmosphere. Stirring was continued for 3 hours before the rapid addition of the 2-(3-bromophenyl) ethanoic imidazolide in the same solvent (60 mL), prepared 20 min. prior by reaction between 3-bromophenylacetic acid (4.47 g, 20.8mmol) and l,l'-carbonyldiimidazole (4.04 g, 24.9 mmol) in dry acetonitrile (60 mL). The reaction mixture was allowed to stir for 17 hours at room temperature, followed by heating to reflux for 1.5hrsbefore quenching by the slow addition of ca. 13% aqueous HCl (100 mL) at 5 0C. The clear biphasic mixture was separated, wherein the organic layer was concentrated by rotary evaporation to a residue and treated with ethyl acetate (80 mL) while the aqueous remains were further extracted into ethyl acetate (2 x 50 mL). The combined organic extracts were washed with a saturated sodium carbonate aqueous solution (2 x 80 mL) and brine (1 x 50 mL), dried over MgSO4, then concentrated in vacuo to afford the desired 4-(3-bromophenyl)-3-oxo-butyric acid ethyl ester (Scheme 7, A) as a clear yellow oil (5.93 g, quant).

References:

WO2006/41404,2006,A1 Location in patent:Page/Page column 84-85; 130