Hydrochloric Acid → 2-(4-Fluorophenoxy)-5-nitro-α-oxobenzenepropanoic acid

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Reaction Steps

183.4 G. of 2-(4-fluoro-phenoxy)-5-nitro-benzaldehyde are stirred at reflux for 20 minutes together with 71 g. of potassium bicarbonate and 82 g. of acetylglycine in 395 ml. of acetic anhydride. Then, there are added successively 1.62 liters of glacial acetic acid, 870 ml. of water and 675 ml. of concentrated hydrochloric acid, and the mixture is stirred for 5 hours at reflux. The resulting mixture is cooled and 1.2 liters of water are added. The mixture is extracted with 3.1 liters of methylene chloride in 3 portions. The methylene chloride solutions are washed twice with 2 liters of water each time and subsequently extracted with a solution of 250 g. of sodium carbonate in 4.5 liters of water. The obtained bicarbonate solutions are acidified with hydrochloric acid and extracted with ethyl acetate. The ethyl acetate solutions are dried over sodium sulfate and evaporated in vacuo. The crystalline residue is boiled out with 400 ml. of benzene. The crystals are removed by filtration and there is obtained 2-(4-fluoro-phenoxy)-5-nitro-phenylpyruvic acid having a melting point of 142°-143° C. By concentration of the filtrate, there is obtained an additional amount of this compound.

Provenance & Evidence