The Darapsky degradation, by which a carbethoxy group is replaced by an amino group, has been applied successfully to substituted cyanoacetic esters for the preparation of 10 amino acids. The esters were formed by condensation of ethyl cyanoacetate with alkyl or arylalkyl halides. The hydrazides were obtained by treatment of the esters with hydrazine hydrate and identified by their anisal derivatives. Diazotization of the hydrazides gave rise to azides. These were transformed into carbethoxyaminonitriles by refluxing with absolute ethanol. The urethanes, on acid hydrolysis, yielded the amino acids. The following amino acids were synthesized: DL-β-methylleucine, DL-α-amino-β-methylisoheptanoic acid, DL-α-amino-β-cyclohexylpropionic acid, DL-C-o-methylcyclohexylglycine, DL-C-m-methylcyclohexylglycine, DL-C-p-methylcyclohexylglycine, DL-C-o-xylylglycine, DL-C-m-xylylglycine, DL-C-p-xylylglycine, DL-p-ethylalanine.