56 THE CHEMICAL CONSTITUTION OF THE PROTEINS 



Udransky and Baumann, and ornithine was therefore a, S-diaminovaleri- 

 anic acid, the hydrolysis of ornithine taking place according to the 

 equation : 



CH 2 CH 2 CH 2 CH COOH CH 2 CH 2 CH 2 CH 2 



I I =co 2 + i i 



NH 2 NH 2 NH 2 NH 2 



Ornithine Putrescine 



The expected synthesis of a-S-diaminovalerianic acid, which was 

 attempted by Willstatter in 1900, by th'e action of ammonia upon a-S- 

 dibromovalerianic acid, led to the synthesis of a-pyrrolidine-carboxylic 

 acid, and only in the following year was the synthesis of this important 

 naturally occurring diamino acid accomplished by E. Fischer. He 

 made use of Gabriel's phthalimide method with a slight modification 

 and obtained ornithine by the following series of reactions : 



ry-phthalimidopropylmalonic ester was prepared from potassium 

 phthalimide, propylene bromide and sodium malonic ester : 



,COv X COOC 2 H 5 



C 6 H/ >NK+Br.CH 2 .CH 2 .CH 2 .Br + Na.CH/ 



^C0 / \COOC 2 H 5 



CCX X COOC 2 H 5 



/ 



= NaBr + KBr + C 6 H N . CH 2 . CH 2 . CH 2 . CH 



\ 



COOC 2 H 5 



On bromination this gave phthalimidopropylbromomalonic ester, 



/CO, ,COOC 2 H 5 



C 6 H 4 ( )N . CH 2 . CH 2 . CH 2 . C^-Br 



\CCK \COOC 2 H 5 



which, on treatment with ammonia, did not give the desired result. On 

 hydrolysis, however, and by loss of carbon dioxide, it is converted into 

 S-phthalimido-a-bromovalerianic acid, 



/ C \ X H 



C 6 H 4 <( ">N . CH 2 . CH 2 . CH 2 . C^-Br 



\CO/ \COOH 



On treatment with ammonia, whereby Br is exchanged for NH 2 , and 

 on subsequent hydrolysis, this acid yielded a-S-diaminovalerianic acid 

 or ornithine, 



H 2 N . CH 2 . CH 2 . CH 2 . CH(NH 2 ) . COOH. 



The dibenzoyl compound only differed from Jaffe's ornithuric acid 

 by being optically inactive. 



By a very similar series of reactions Sorensen has also synthesised 

 ornithine : he first introduces the phthalimido group into the sodium 



