The molecule is a dicarboxylic acid that is 5,5',6,6'-tetrahydroxy[biphenyl]-3,3'dicarboxylic acid in which one of the hydroxy groups that is meta to a carboxy group has been converted into the corresponding methyl ether. It is a member of hydroxybiphenyls, a carboxybiphenyl, a member of catechols, an aromatic ether and a dicarboxylic acid. It is a conjugate acid of a 5,6,6'-trihydroxy-5'-methoxy[biphenyl]-3,3'-dicarboxylate.
3-(5-carboxy-2-hydroxy-3-methoxyphenyl)-4,5-dihydroxybenzoic acid