411 Pyrans and Related Substances 



of fulvic acid, also produces a variety of other metabolites, 

 including griseofulvin and mycelianamide. There seems 

 to be no close relationship between these compounds and 

 the three mentioned above, however. 



The biosyntheses of sclerotiorin,-' citromycetin- and cit- 

 rinin-' -^ have been investigated by using C'^-labeled ace- 

 tate, formate and methionine. 



The two studies of citrinin (III) were in agreement, the 

 results of both indicating origin from a 10-carbon atom 

 polyketomethylene chain in the sense of (II). 



The carbon atoms 11, 12 and 13 in (III) were contrib- 

 uted by methionine or formate. 



Sclerotiorin also is acetate derived with contribution of 

 three carbon atoms by formate. 



Citromycetin (V) is derived entirely from seven acetic 

 acid units, CH3— COOH (CH3— COOH) and yields the 

 labeUng pattern shown below. 



It would appear that purpurogenone should also be de- 

 rived from seven acetate units. 



- A. J. Birch, P. Fitton, E. Pride, A. J. Ryan, Herchel Smith and 

 W. B. Whalley, /. Chem. Soc, 4576 (1958). 



^ Erwin Schwenk, George J. Alexander, Allen M. Gold and Dean F. 

 Stevens, ;. Biol. Chem. 233 1211 (1958). 



