Aerobic oxidation of 1,3,5-triisopropylbenzene using N-hydroxyphthalimide (NHPI) as key catalyst
作者:Yasuhiro Aoki、Naruhisa Hirai、Satoshi Sakaguchi、Yasutaka Ishii
DOI:10.1016/j.tet.2005.08.087
日期:2005.11
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 02 in the presence of a catalytic amount of NHPI and azobisisobutyronitrile (AIBN) at 75 degrees C. Upon treatment of the resulting products with sulfuric acid followed by acetic anhydride led to 5-acetoxy-1,3-diisopropyl benzene and 3,5-diacetoxy-1-isopropyl benzene as major products and a small amount of 1,3,5-triacetoxybenzene. When t-butyl peroxypivalate (BPP) was employed as a radical initiator, the oxidation could be achieved in good yield even at 50 degrees C. This oxidation provides a facile method for preparing phenol derivatives bearing an isopropyl moiety, which can be used as pharmaceutical starting materials. (c) 2005 Elsevier Ltd. All rights reserved.