134 



AARON BENDICH 



NH 



II 

 C 



/ \. 

 H NH, 



CN 



+ 



CHN=N— 



^CN 



n-C4H90H 



n-CiHgONa 



(70-80%) 



Formamidine Phenylazomalononitrile 



NH2 



NH, 



N=N— ( 



*N 

 I ., 



NH2 

 4,6-Diamino-5-phenyl- 

 azopyrimidine 



Zn, H2O 



NHo 



(60-85%) 



■^ *N 



\N/*\ 



NH2 

 4,5,6-Triamino- 

 pyrimidine 



HCOOH, HC0NH2 



NH2 



"N 

 I 



(90%) 



HCONH2 



(75%) 



(90%) 



HCOOH 



NH2 



^N 

 I . ^ 



NHCHO 



NH2 



H 



Adenine 



4, 6-Diamino-5-f ormyl- 

 aminopyrimidine 



c. From, Imidazoles 



It is of interest that the rat transforms 4-amino-5-imidazolecarboxamide 

 into nucleic acid purines'"* (cf. Chapters 23 and 25) since the conversion of 

 this and other imidazoles into a variety of purines may be achieved chemi- 

 cally as well. In earlier syntheses of purines by this route (cf. Lythgoe^^^), 

 the intermediate imidazoles were relatively inaccessible. This has been 

 remedied to a great extent by newer methods of preparation. ^°' .448-452 



The fusion of 4-amino-5-imidazolecarboxamide with urea leads to the 

 formation of xanthine in 75% yield^^^ (cf. Stetten and Fox^^^). When the 



*« C. S. Miller, S. Gurin, and D. W. Wilson, Science 112, 654 (1950) ; /. Am. Chem. Soc. 



74,2892 (1952). 

 "9 I. Heilbron, /. Chem. Soc. 1949, 2099. 



«« A. H. Cook and I. Heilbron, Rec. trav. chim. 69, 351 (1950). 

 «' E. Shaw and D. W. Woolley, /. Biol. Chem. 181, 89 (1949). 

 «2 E. Shaw, /. Biol. Chem. 185, 439 (1950). 

 *" M. R. Stetten and C. L. Fox, Jr., J. Biol. Chem. 161, 333 (1945). 



