THE SYNTHESIS OF THE PROTEINS 11 



C 6 H 5 . CO NH . CH 2 . CO NH . CH . COOH 



COOH 



CH 2 . 



CH 2 . 



The ester of this compound was converted into the hydrazide by 

 means of hydrazine, 



C 6 H B . CO NH . CH 2 . CO NH . CH . CO . HN . NH a 



CH 2 .CO.HN.NH 2 



from which hippuryl-aspartic acid azide was obtained by the action of 

 nitrous acid : 



C 6 H 5 .CO NH.CH 2 .CO NH.CH.CO.N 3 



CO.N 3 



This reacted in ethereal solution with aspartic ester yielding hippuryl- 

 asparagyl-aspartic ester from which the free acid, 



C 6 H 5 . CO NH . CH 2 . CO NH . CH . CO NH . CH . COOH 



CH 2 .COOH 



CH 2 .CO NH.CH.COOH 

 CH 2 .COOH 

 was obtained by saponification with baryta. 



The hydrazide of this compound was then prepared from the ester 

 in the usual manner, and from this the azide, which did not, however, 

 possess the normal structure, but that of the hydrazi-azide, 



C 6 H 5 . CO NH . CH 2 . CO NH . CH . CO NH . CH . CO . N 3 



CH 2 . CO . NH 

 CH 2 .CO.NH 

 CH 2 . CO NH . CH . CO . N 3 



The condensation product of this compound with aspartic ester was 

 not isolated, but the complex hippuryl-disaspartyl-aspartic acid hydrazi- 

 hydrazide, its hydrazine derivative, 



C 8 H 5 . CO . NH . CH 2 . CO NH . CH . CO NH . CH . CO NH . CH . CO HN . NH 2 



Lj.CO.NH CH 2 .CO HN.NH 2 

 CH 2 .CO.NH CH 2 .CO HN.NH 2 



CH 2 .CO NH.CH.CO NH.CH.CO HN.NH 5 



was obtained when the condensation product was treated in alcoholic 

 solution with hydrazine hydrate. 



Just in the same way hippuryl-aspartyl-glycine ester, 



C 6 H 5 . CO . NH . CH 2 . CO NH . CH . CO NH . CH 2 . COOC 2 H 5 



CH 2 . CO NH . CH 2 . COOC 2 H 5 



