The molecule is a monocarboxylic acid anion that is the conjugate base of pentalenolactone D, obtained by deprotonation of the carboxy group; major species at pH 7.3. It is a conjugate base of a pentalenolactone D.
(1S,4aR,6aS,9aR)-1,8,8-trimethyl-2-oxo-1,4,4a,6a,7,9-hexahydropentaleno[1,6a-c]pyran-5-carboxylate