1 1 8 THE CHEMICAL CONSTITUTION OF THE PROTEINS 



valerianic acid, the hydrolysis of ornithine taking place according to 

 the equation : 



CH Q CHo CH 2 CH COOH CH 2 CH 3 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, 8-diaminovalerianic acid, which was 

 attempted by Willstatter in 1900, by the action of ammonia upon a, S- 

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

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

 naturally occurring diamino acid was 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 : 

 y co x x cooc 2 H 6 



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



\CCK \COOC 2 H 5 



/COv xCOOC 2 H 5 



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



\CCK \COOC 2 H S 



On bromination this gave phthalimidopropylbromomalonic ester, 



/COv /COOCaHjj 



C 6 H 4 <; >N . CH 3 . CH 2 . CH 2 . C^-Br 



>OK X 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, 



X C \ / H 



C 6 H / )N . CH 2 . CH 2 . CH 2 . C-Br 



^CO/ \COOH 



The Br atom is exchanged for the NH 2 group by treatment with 

 ammonia, and on subsequent hydrolysis, this acid yielded a, S-diamino- 

 valerianic 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 

 malonic ester and then allows 7-bromopropylphthalimide to act upon 

 this ; the new substance is treated with sodium and alcohol, and, on 



