172 Dr Latham, On the Composition of Albumen. [Feb. 6, 



0,H 9 . CH {^ 2 + 2H 2 = C 4 H 9 . CH |^ H + NH S . 



leucine 



Leucine prepared in this way is not quite identical with animal 

 leucine. The explanation I venture to suggest is that just as sarco- 

 lactic acid is a compound of ethidene and ethene lactic acids, so 

 leucine is a compound of two or more amido-acids of which a second 

 may be prepared in the following manner : — 



By the oxidation of the pentyl alcohol, diethyl carbinol, we ob- 

 tain diethyl ketone* — 



C 6 H U . HO + = H 2 + (C 2 H 5 ) 2 CO 

 diethyl carbinol diethyl ketone 



Tienian-f- has shown that this with hydrocyanic acid is converted 

 into a cyanhydrin, which, acted upon by ammonia and then by an 

 acid, produces leucine — 



(C 2 H 6 ) 2 CO + HON = (C 2 H 6 ) C {™ 



diethyl-ketone-cyanhydrin 



(C 2 H 6 ) 2 {£* + NH 3 = H 2 + (C 2 H 5 ) 2 C j™ 2 



cyanhydrin 



(C 2 H 6 ) 2 j™ 2 + 2H 2 = (C 2 H 6 ) 2 C |^ H + NH 3 



(NH, 

 = C 6 H 10 | COOH + NH 8 



amido-diethyl acetic acid 

 or leucine 



3. Similarly by the oxidation of propyl alcohol, propionic 

 aldehyde is obtained, which may be converted into propene cyan- 

 hydrin \ — 



/ATT 



C 2 H 6 .CH0 + HON = C 2 H 5 .CH izjJT 



propionic aldehyde propene cyanhydrin 



By oxidation of isopropyl alcohol, dimethyl ketone or acetone 



* Fownes, p. 153. T Bcrichte, xiv. s. 1975. 



X Fownes, p. 329. 



