Hydrochloric Acid → 4-Fluorohippuric acid

A solution of glycine (15 g, 0.2 mol) in 175 mL of 5% aqueous sodium hydroxide is cooled to 10° C. to 15° C. p-Fluorobenzoyl chloride (31.6 g, 0.2 mol) is then added, dropwise, to the mixture and stirred vigorously for 0.5 hour, while maintaining the temperature of the mixture at about 10° C. to 15° C. The pH of the reaction mixture is maintained at pH>9 by the dropwise addition at 50% aqueous sodium hydroxide. The mixture is stirred at 10° C. to 15° C. for two hours with the resulting clear solution then acidified with concentrated HCl to pH=1. The resulting product is filtered off, washed with water (2×100 mL) and air dried to give a white solid (30.8 g, 78.1%); mp=161°-163° C.