1,3,6-Cycloheptatriene-1,2-dicarboxylic anhydride, 3,6-dihydroxy-5-oxo- 1H-Cyclohepta(c)furan-1,3,6-trione, 4,7-dihydroxy- 606-39-3 NSC 149772 Stipitatonic acid Stiptatonic acid