4,6-dihydroxy-2-(hydroxymethyl)-3,5-dimethylbenzoate + H(+) <=> 5,7-dihydroxy-4,6-dimethylphthalide + H2O
4,6-dihydroxy-2-(hydroxymethyl)-3,5-dimethylbenzoate + h(+) <=> 5,7-dihydroxy-4,6-dimethylphthalide + h2o