Pfizer Handbook of Microbial Metabolites 



406 



HO 



HO 



CH2OH 



I 



c=o 



OH 



J 



c — c 



OH 



c=o 



H O 



2, 5-Diketogluconic Add 



o=c 



CHOH 



C OH 



H / OH 



— 2H^ 

 — H2O 



c=o 



OH 



C— C 



OH 

 Enol Form 



-2H,0 



o=c 



OH H 



|- I 



OH H 



1 I 



c=c 



OH COOH 



Rubiginic Acid 



— CO2 



OH H 



I I 



c=c 



1 I 



OH H 



Rubiginol 



o=c 



c=c 



1 1 



H COOH 

 Comenic Acid 



