Substituted hydroxybenzaldehydes are important feedstock materials for the pharmaceutical and perfume industries.[1, 2] These compounds are commonly made by the selective oxidation of aromatic methyl groups. However, this chemical reaction is difficult and often proceeds to the carboxylic acid derivative. Thus, 4-hydroxy-3, 5-dimethylbenzaldehyde (HDB) is a valuable intermediate, especially for the preparation of drugs.[3–5] A number of ...
