2, 3-Dimethoxy-5-methyl-p-benzoquinone (IV), a synthetic intermediate of ubiquinones was prepared in excellent yield by oxidation of 2, 3-dimethoxy-5-methyl-p-phenylenediamine dihydrochloride (XIV) obtained via 3, 4-dimethoxy-2, 5-dinitrobenzaldehyde (XII) from vanillin. A number of p-benzoquinones related to IV were also synthesized for biological evaluation.
