Pfizer Handbook of Microbial Metabolites 



548 



J. G. Moffatt and H. G. Khorana, /. Am. Chem. Soc. 81 1265 



(1959). (Synthesis) 



1047 Puromycin, C22H29O5N7, white crystals, m.p. 175.5-177° 

 (uncorr.), [a]D^^ —11° (c 1 in ethanol). 



HOCH 



0==C— CH— CH 



OCH3 



Streptomyces albo-niger 



J. W. Porter, R. I. Hewitt, C. W. Hesseltine, G. Krupka, J. A. 

 Lowery, W. S. Wallace, N. Bohonos and J. H. Williams, Anti- 

 biotics and Chemotherapy 2 409 (1952). 



Coy W. Waller, Peter W. Fryth, Brian L. Hutchings and 

 James H. Williams, /. Am. Chem. Soc. 75 2025 (1953). 

 ( Structure ) 



B. R. Baker, Robert E. Schaub, Joseph P. Joseph and 

 James H. Williams, ibid. 77 12 (1955). (Synthesis) 



0. PTERIDINES AND FLAVINES 



Pteridines (pterins), originally discovered in insects, 

 occur widely, and several have been isolated from mi- 

 crobial sources. The most important of these from the 

 metabolic standpoint is folic acid. This substance, or 

 group of related substances, is a vitamin for most mam- 

 mals and plants and for some microorganisms unable to 

 produce it. Pure folic acid first was isolated from liver 

 and from yeast. The triglutamyl form was isolated from 

 a corynebacterium, and the heptaglutamyl derivative, first 

 isolated from yeast, since has been found in a variety of 

 microorganisms. The reason for the polypeptide chains is 

 not clear. These forms are as effective as folic acid in 



