A facile synthesis of 3,5-dimethyl-4-hydroxybenzaldehyde via copper-mediated selective oxidation of 2,4,6-trimethylphenol

2,4,6-Trimethylphenol was selectively oxidized to 3,5-dimethyl-4-hydroxybenzaldehyde in very good yields using catalytic or equivalent amounts of CuCl2 in the presence of K2CO3 and H2O2 in i-PrOH at 65 °C. The effect of the molar ratios of CuCl2, K2CO3 and H2O2 on the yields and product distribution was examined. The oxidation reaction was found to proceed smoothly without the use of additives or ligands which were reported to be necessary.