The kinetics and mechanism of the hydrolysis of 2,3-(phenylmethylenedioxy)benzoic acid (OO?-benzylidene-2,3-dihydroxybenzoic acid)

The hydrolysis of OO-benzylidene-2,3-dihydroxybenzoic acid is considerably faster than that of OO-benzylidene-3,4-dihydroxybenzoic acid and OO-benzylidenecatechol. The pH-rate profile is of the form: kobs=k1/(1 +Ka/10–pH). The high rate is associated with the k1-term which probably arises from intramolecular general-acid catalysis. This kinetic parameters of this reaction are compared with those for the formally analogous inter-molecularly general-acid catalysed hydrolysis of benzylidenecatechol. OO-Benzylidene-2,3-dihydroxybenzoic acid is not intramolecularly hydrogen bonded in dilute solutions in carbon tetrachloride