Oxidation of Some 2-Methoxyphenols with Chlorous Acid

Article abstract of DOI:10.1021/jo00132a008

Oxidation of 3-ethoxy-4-hydroxy-, 4-hydroxy-3-methoxy-5-methyl-, 3-chloro-4-hydroxy-5-methoxy-, and 2-hydroxy-3-methoxybenzaldehyde with chlorous acid gives, by oxidative aromatic ring cleavage between the oxygen-bearing carbon atoms, derivatives of (2Z, 4Z)-2,4-hexadienedioic acid in low yields.Chlorous acid oxidation of 2-methoxyphenol and 3-hydroxy-4-methoxybenzaldehyde yields methoxy-1,4-benzoquinone and 5,5-dichloro-6,6-dihydroxy-2-methoxy-2-cyclohexene-1,4-dione, respectively.The hydrate as well as the corresponding methyl hemiacetal undergoes base-catalyzed ring contraction to a derivative of 1-hydroxy-4-oxo-2-cyclopentenecarboxylic acid.The kinetics of the ring contraction of the hydrate was investigated in aqueous solutions in the pH range 1.15-3.65, where the rearrangement appears to be subject to specific base catalysis.