The molecule is a monocarboxylic acid anion that is the conjugate base of pentalenolactone F, obtained by deprotonation of the carboxy group; major species at pH 7.3. It is a conjugate base of a pentalenolactone F.
(1R,4aR,6aS,9aR)-8,8-dimethyl-2-oxospiro[4a,6a,7,9-tetrahydro-4H-pentaleno[1,6a-c]pyran-1,2'-oxirane]-5-carboxylate