154 pteroylglutamic acid 



5. Pteroyl Derivatives of Different Amino Acids 



A large number of pteroyl derivatives of different amino acids have been 

 prepared; the only one that functions as an antagonist is the aspartic acid 

 analog." The inhibition index is 40 for S. faecalis and 2000 for L. casei and 

 is constant over relatively large ranges of concentration. The inhibition 

 ratio for S. faecalis in the presence of pteroic acid is decreased to 2. Pteroyl- 



HOOC 



I H 

 HC-N-C 



I 



HjC 



I 



HjC 



I 



HOOC 



Benzimidazole-2-methyl-p-aminobenzoylglutamic acid'''' 

 Growth promoter 0.01 '^c as active as PGA for S. faecalis R 



HOOC N- 



h6-S-s/ Vn-c-c. 



.==/ H H^ >| 

 H^C 



I 



H2C 



I 



HOOC 



Benziraidazole- 2- methyl- p-aminobenzene sulfonylglutamic acid™ 

 Growth inhibitor inhibition ra4-io for S. faecalis R :S000 



HOOC ^^^^N. 



HC-N-C( V^'-VA^N 



I H \=/ H 



H2C 



I 



H2C 



I 



HOOC 



Quinazohne-4-p-anunobenzoylgiutamic acid '° 

 Growth promoter 1 to 10 '/o as active as PGA 



HOOC Hr^-^\^N 



HC-N-cf^N-C-4^1^ 



HaC O 



I 

 H2C 



I 



HOOC 



Quinazoline-2-carboxylyl-/>;umiiubonzo> Igiutamic acul^" 

 Antagonist inhibition ratio for L casci -'600, 000 



Fig, 10. Modification of the pteridine nucleus of pteroylglutamic acid. 



