Oxidation of Methoxy- and/or Methyl-Substituted Benzenes and Naphthalenes to Quinones and Phenols by H2O2 in HCOOH

Article abstract of DOI:10.1246/bcsj.62.1652

The oxidation of a number of arenes (methoxybenzenes, methylbenzenes, and naphthalenes) to quinones and phenols by H2O2 in HCOOH has been examined.Methoxybenzenes were much more easily oxidized to p-benzoquinones than methylbenzenes (e.g., 1,3,5-trimethoxybenzene was oxidized to 2,6-dimethoxy-p-benzoquinone in a 75percent yield and 1,2,4-trimethylbenzene to 2,3,5-trimethyl-p-benzoquinone in a 16percent yield).Electron-withdrawing substituents, such as nitro, cyano, and chloro groups, lowered the conversion of reactants and changed the product selectivity from quinones to phenols.Methoxybenzonitriles were oxidized to corresponding phenols in a moder ate yield (e.g., 2,6-dimethoxybenzonitrile to 3-hydroxy-2,6-dimethoxybenzonitrile in a 39percent yield and a 64percent selectivity).