The first systematic study on the aerobic oxidation of 1, 3, 5-triisopropylbenzene was examined by the use of N-hydroxyphthalimide (NHPI) as a key catalyst. It was found that 1, 3, 5-triisopropylbenzene was efficiently oxidized with O2 in the presence of a catalytic amount of NHPI and azobisisobutyronitrile (AIBN) at 75° C. Upon treatment of the resulting products with sulfuric acid followed by acetic anhydride led to 5-acetoxy-1, 3- ...