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.

4-Mono-and 4,4-disubstituted-3-imino-2-benzoyl-5-pyrazoones have been prepared from the corresponding ethyl mono-or disubstituted cyanoacetates and N-benzoylhydrazine. The presence of the imino group in 4, 4-disubstituted-3-imino-2-benzoyl-5-pyrazolones was ascertained by the hydrolysis of 4, 4-dibenzyl-3-imino-2-benzoyl-5-pyrazolor1e into 4, 4-dibcnzyl-3-0x0-2-benzoyl-5-pyrazolone. In order t o prove that the benzoyl group in these pyrazolones was not in Position 1, the synthesis of 4-benzyl-3-amino-1-benzoyl-5-pyrazolone was attempted from 4-beruyl-3-carbethoxy-1-benzoyl-5-pyrazolone through a Curtius degradation of the 3-carbethoxy substituent into a 3-amino group. I t was found that the 1-benzoyl group was hydrolyzed a t the same time as the 3-carbethoxyamino substituent. The ~iltraviolet absorptio~r spectra of all these compounds are reported and discussed briefly. INTRODUCTIONPyrazolones prepared from ethyl mono-or disubstituted cyanoacetates and hydrazine have been previously reported (1,3). Phenylhydrazine and semicarbazide were condensed in the same way to yield the corresponding 2-phenyl (I) and 2-carboxanlido-5-pyrazolones (2).I t was thought of interest to study the condensation of N-benzoylhydrazine under similar conditions. By reacting ethyl monosubstituted cyanoacetates (I) with N-benzoylhydrazine (11) in the presence of sodium ethylate, 4-monosubstituted-3-imino-2-benzoyl-5-pyrazolones (111) were obtained (Table I).The reaction of ethyl disubstituted cyanoacetates (IV) with N-benzoylhydrazine under similar conditions yielded 4,4-disubstituted-3-imino-2-benzoyl-5-pyrazolones (V) (