THE CHEMICAL CONSTITUTION OF THE UNITS 115 



for this constitution was only given in 1 890 by L. Wolff who syn- 

 thesised glutamic acid from laevulinic acid. Dibromolaevulinic acid is 

 obtained by bromination, and this when boiled with water gives diacetyl 

 and glyoxylpropionic acid ; diisonitrosovalerianic acid is formed from 

 the latter, on treatment with hydroxylamine : 



CH 3 



Br 



I 



B, 

 CH 2 



CH 2 

 COO 



H 



Laevulinic acid 



HNOH 



OOH 



OOH 



Dibromolaevulinic Glyoxylpropionic 



acid 



acid 



COOH 



Diisonitrosovalerianic 

 acid 





NaOH 



This is converted into furazanpropionic acid by sulphuric acid and then 

 into cyanonitrosobutyric acid by caustic soda. Saponification changes 

 the cyanonitrosobutyric acid into a-nitrosoglutaric acid from which 

 glutamic acid is obtained by reduction: 

 CH = 



A = 



CH 2 

 CH 2 



COOH 



Furazanpropionic 

 acid 



This appears to be the only recorded synthesis of glutamic acid. 



The next member of this homologous series, a-amino-adipic acid, 

 has been prepared by Sorensen from phthalimidosodium malonic ester 

 and chlorobutyronitrile in the following way : 



COOC,H 5 COOC 2 H 5 



I yCH 2 .CH 2 .CH 2 CN 

 ,CO V 4. ci . CH_ . r.R- . rH.r.N = c<^ / CO \ 



N / \p rr 



\ /^6 H 4 



. CH 2 . CH 2 . CH 2 CN 



+ NaCl 



COOC a H 5 



COOC 2 H 5 



/CHa.CHa. 

 .CO 



COONa 



| . 



| \NH . COC 8 H 4 COONa 

 COONa 



COOC a H 5 



COONa 



I /CHa. CH a .CH 2 . COONa 

 -C<( +2C 2 H 5 



I \NH. CO. C 6 H 4 . COONa 



COONa 



CH 2 .CH 2 . 



= H.C.NH 2 



COOH 



C a H 4 (COOH) 2 + CO 2 



8 * 



