1882.] Dr Latham, On the Composition of Albumen. 171 



C 4 H 9 . CHO + NH 3 = C 4 H 9 . CH (NH 2 ) OH * 

 valeral ammonia. 



C 4 H fl .CH (NH 2 ). OH + HCN + H 2 = C 4 H 9 . CH j^ H +NH 3 t 



leucine 



This is the usual way of obtaining leucine artificially ; but Tiemann 

 has shown;}; that the amido-acids, both of the fatty and aromatic 

 series, may be obtained by converting the aldehydes and ketones 

 into cyanhydrins and then into amido-nitriles or cyanamides. We 

 may consequently also have the following changes : 



4 H 9 . CHO + HON = C 4 H 9 . CH j°|f 



pentene cyanhydrin 



C 4 H 9 .CH |™ +NH 8 =OH B .CH j™ 2 + H 2 



pentene cyanamide 



* Watts, Dictionary, Vol. v. p. 974. t Fownes, p. 385. 



J Berichte der deutsch. chem. Gesell. xiv. s. 1985. " The amido acids of the 

 fatty series are easily obtained by the familiar reactions which take place on treating 

 aldehyde ammonia with hydrochloric and hydrocyanic acids, and which led Strecker 



to the discovery of alanine The reactions indicated by Strecker take place 



unquestionably according to the following general formula : 



[ NH 2 l NH 2 



R ... C ) H + HCN = R ... J H + H 2 0, 

 j OH ' CN 



and 



(NH 2 

 R ... C -j H + 2H 2 + HC1 = R ... CH(NH 2 ) ... COOH + H 4 NC1. 

 (CN 

 The question arises, whether the cyanamide 



(NH 3 

 R...C-JH 

 (CN 



could not be obtained more readily from the cyanhydrides of the aldehydes 



(CN 

 R ... C-JH 



(oh 



by digesting them with ammonia, expecting the ultimate change to be as follows : 



( CN ( CN 



R... O-JH +NH 3 = R...CJH + H 2 0. 

 ( OH ( NH 2 



The truth of this supposition has been confirmed by experiment." — Berichte, xm. 

 8. 382. 



13—2 



