I, : _>4H,0 = 



THE LINKING TOGETHER OF AMINO ACIDS 25 



except that benzoic acid appears in the place of hippuric acid. Hip- 

 puryl aspartic acid azide and aniline give a compound which is half 

 anilide and half carbanilide, and this on hydrolysis is converted into 

 a-/3-diaminopropionic acid, hippuric acid, aniline and carbonic acid : 

 C 6 H. . CO . NH . CH, . CO NH . CH . CO NH . C,H, 



CH,.NH.CO.NH.C,H 



C.H.. CO . NH . CH, . COOH + NH, . CH . COOH 



i+ 2C a H ft . NH, + CO, 

 H, . NH, 



The normal urethane formed by the action of alcohol on hippuryl 

 aspartic acid azide yields on hydrolysis hippuric acid, carbonic acid, 

 alcohol and aminoacetaldehyde : 



C,H, . CO . NH . CH, . CO NH . CH . NH . COOC.H, 



NH . COOC,H. 



C,H 8 . CO . NH . CH, . COOH + aNH, + NH, . CH, . CHO + CO, + aC,H,OH 

 The first reaction shows the conversion of a compound belonging to 

 the series of dibasic monoamino acids into a diaminomonocarboxylic 

 acid ; in the second reaction a dibasic amino acid is changed into the 

 aldehyde of the monobasic glycine. 



Finally, propylenediamine was obtained when the urethane, resulting 

 from the action of alcohol upon hippuryl-$-aminobutyric acid azide, was 

 hydro lysed : 



C 8 H 5 . CO . NH . CH, . CO NH . CH(CH,) . CH, . NH . COOC,H 5 + 3H,O = 

 C 6 H B . COOH + NH, . CH, . COOH + NH, . CH(CH,) . CH, . NH, + CO, + C,H S OH 

 which shows the conversion of an amino acid derivative into a diacid 

 base. 



The further work of Curtius and his pupils, published in 1906, is 

 concerned with the action of nitrous acid upon the polyglycine com- 

 pounds : diazoacetyl glycine ester N 2 : CH . CO NH . CH, . COOC,H 5 

 was formed by the action of nitrous acid upon glycyl-glycine ester 

 hydrochloride and diazoacetyl glycyl-glycine ester, 



N, : CH . CO NH . CH, . CO NH . CH, . COOC,H,, 



by its action upon diglycyl-glycine ester hydrochloride, and similarly 

 diazoacetyl-bisglycyl-glycine ester. 



By the action of ammonia on the first body diazoacetyl glycine 

 amide, 



N, : CH . CO NH . CH, . CO . NH,, 



was formed, and on the latter diazoacetyl glycyl-glycine amide, 



N, : CH . CO NH . CH, . CO NH . CH, . CO NH,. 



These are yellow substances, but when excess of ammonium hydroxide 

 or liquid ammonia is added to the esters colourless substances are 



