Ethyl benzamidomalonate

A mixture of 58 g. (0.32 mole) of ethyl aminomalonate (p. 144), 50 ml. of pyridine, and 250 ml. of water is stirred while 48.5 g. (0.35 mole) of benzoyl chloride is added at such a rate that the temperature of the reaction mixture remains below 50°. The mixture is cooled to room temperature, and the white crystalline precipitate is collected by filtration and dried. The solid is recrystallized by dissolving in the minimum amount of hot benzene and slowly adding six times the volume of petroleum ether. There is obtained 92.4 g. (90%) of ethyl benzamidomalonate melting at 73-74°. 

Twenty-five grams (0.088 mole) of ethyl benzamidomalonate (p. 145) and 24 g. (0.13 mole) of isobutyl iodide are added to a solution of 2.1 g. of sodium in 200 ml. of dry absolute ethanol (p. 142). The mixture is heated under reflux for 3,5 hours with protection from... 

A large number of a-amino acids have been prepared by various modifications of the Sorensen m.ethod ° in which acylaminornalonic esters are alkylated and degraded. Ethyl acetamidomalonate (R = CHjethyl benzamidomalonate (R = C Hs), and ethyl formamidomalonate (R = H) have been used. The acetyl group is more easily introduced and removed than the benzoyl group. ... 

The amino acids listed below are prepared in similar manner by reaction of the proper organic halide with benzamidomalonic ester (p. 145). The halides used and the yields of dl-amino acid obtained are given in parentheses phenylalanine (benzyl chloride, 90%), aspartic acid (ethyl chloroacetate, 62%) and valine (isopropyl iodide, 71%). 

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