56 THE CHEMICAL CONSTITUTION OF THE PROTEINS 



Udranskyand 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, CH 2 CH 9 



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 the action of ammonia upon a-- 

 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 : 



7-phthalimidopropylmalonic ester was prepared from potassium 

 phthalimide, propylene bromide and sodium malonic ester : 



/co x x cooc 2 H 5 



C 6 H/ pNK +Br . CH 2 . CH 2 . CH 2 . Br + Na . CH/ 



\CCK \COOC 2 H 5 



/CO, X COOC 2 H 5 



= NaBr + KBr + C 6 H / ">N . CH 2 . CH 2 . CH 2 . CH/ 



XXK X COOC 2 H 5 



On bromination this gave phthalimidopropylbromomalonic ester, 



cooc 2 H 5 



, CH 2 . CH 2 . CH 2 



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, 



/ C0 \ /* 



C 6 H 4 \ ^N.CH 2 .CH 2 .CH 2 .C<J-Br 



\CCK \COOH 



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

 on subsequent hydrolysis, this acid yielded a-8-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 



