112 



PTEROYLGLUTAMIC ACID 



R- 



HCOOH 

 AC2O 



HCOOH 



h4 



R-N-CH 



hc=o 



HH 



N N^ 



I ^ 



HC=0 °" 



H 



XVII 



(5,10-Difoimyl-5,6,7, 

 tetrahydro PGA) 



OH- 



HCOOH 

 AC2O 



H 



R-NHCHj-L-, 



H^ 

 HC = 

 XII 



(Synthetic citrovorum factor 

 leucovorin, folinic acid-SF) 



OH- 



HCl 



/ 



H-i 

 CH 



H H 



R-N 



H 



\, 



-i\H, 



N 

 OH 



CH' 



XIII 



(Isoleucovorin chloride) 



ci- 



XIX 



(Anhydro- 

 leucovorin-B) 



0.1 A' 

 HCl 



H2O 100°, 

 then cool 



HOOC 



I II 



CHNH-C 



I 

 R= CH2 



I 



CH2 



I 

 HOOC 



Fi(j. 7. Choinical transl'ornuitioiis in the sjiithosi.s of leucovorin from pteroylglu- 

 tamic acid. 



pH 4 

 100° 



HH 



XVIII 



(Anhydroleucovorin-A) 



^NHj 



N 



J 



