122 PTEROYLGLUTAMIC ACID 



reported success by four different methods. Method P • - consisted in re- 

 acting equimolecular amounts of 2,4,5-triamino-6-hydroxypyrimidine, 

 p-aminobenzoyl-L-glutamic acid, and 2,3-dibromopropionaldehyde in the 

 presence of an acetate buffer. The resulting product was 15% active. The 

 dihydro compound was formed first, and this oxidized to the aromatic 

 compound during the course of the reaction. The crude mixture was dis- 

 solved in dilute alkali and the impurities removed by precipitation with 

 barium chloride, adjusting to pH 7.0, filtering, and extracting three times 

 with 10 volumes of butanol. The aqueous phase was concentrated, acidified 

 to pH 3.0, and cooled to 0.5°. The precipitate was redissolved in dilute 

 alkali, the solution was treated with charcoal and acidified to pH 3.0, and 

 the active compound was recovered by crystallization from hot water. 



In Method IP> ^ 2,3-dibromopropionaldehyde was reacted with pyridine, 

 and the product was condensed with 2,4,5-triamino-6-hydroxypyrimidine 

 and KI to yield N-[(2-amino-4-hydroxy-6-pteridyl)methyl]-pyridinium 

 iodide. By heating with Na methoxide in ethylene glycol at 140°, this com- 

 pound was condensed and the product was found to contain 15% of the 

 active compound. 



Method IIP involved the reaction of reductone (2,3-dihydroxyacrylalde- 

 hyde) with p-aminobenzoylglutamic acid to form p-(2,3-dihydroxy-2-ene- 

 propylideneamino)benzoylglutamic acid, then esterification and condensa- 

 tion of the ester with 2,4,5-triamino-G-hydroxypyrimidine. 



Method IV^ involved the reduction of 2-amino-4-hydroxy-G-pteridyl- 

 methylpyridinium iodide to 2-amino-4-hydroxy-6-methylpteridine, bro- 

 mination or chlorination, then condensation of the product with the diethyl 

 ester of p-aminobenzoylgiutamic acid. 



These and similar methods have been patented bj' the American Cyana- 

 mid Company.^ 



2 C. W. Waller, B. L. Hutchings, J. H. Mowat, E. L. R. Stokstad, J. H. Bootho, 

 R. B. Angier, J. Semb, Y. SubbaRovv, D. B. Cosulich, M. J. Fahrenbach, M. E. 

 Hultquist, E. Kuh, E. H. Northey, D. R. Seeger, J. P. Sickels, and J. M. Smith, 

 Jr., /. Am. Chem. Soc. 70, 19 (1948). 



3 M. E. Hultquist, E. Kuh, D. B. Cosulich, M. J. Fahrenbach, E. H. Northey, B. L. 

 Hutchings, J. H. Mowat, J. Somb, E. L. R. Stokstad, Y. SubbaRow, and C. W. 

 Waller. /. Am. Chem. Soc. 70, 23 (1948). 



^ R. B. Angier, E. L. R. Stokstad, J. H. Mowat, B. L. Hutchings, J. H. Boothe, C. 



W. Waller, J. Semb, Y. SubbaRow, D. B. Cosulich, M. J. Fahrenbach, IM. K. 



Hultquist, E. Kuh, E. H. Northey, E. H. Seeger, J. V. Sickels, and J. M. Smith. 



Jr., /. Am. Chem. Soc. 70, 25 (1948). 

 "i J. H. Boothe, C. W. Waller, E. L. R. Stokstad, B. L. Hutchings, J. H. Mowat, 



R. B. Angier, J. Semb, Y. SubbaRow, D. B. Cosulich, M. J. Fahrenbach, M. V. 



Hultquist, E. Kuh, E. H. Northey, D. R. Seeger, J. P. Sickels, and J. M. Smith, 



Jr., /. Am. Chem. Soc. 70, 27 (1948). 

 6 American Cyanamid Co., U. S. Pats. 2,442,836, 2,442,837, 2,442,867, 2,443,165, 



