The Chemoselective and Regioselective Hydroxylation or Chlorination onto The Aryl Ring of N-(4-Substituted-Aryl) Nitrones. Preparation of 2-Aminophenols by Regiospecific Ortho-Hydroxylation

Abstract

N-(substituted-aryl) Nitrones, in the reactions with a chlorinating reagent such as trichloroacetyl chloride, oxalyl chloride, or thionyl chloride, produce a hydroxylation or a chlorination onto the aryl ring of the arylnitrones. The chemoselectivity and the region selectivity (hydroxylation or chlorination) depend largely on the nature of chlorinating reagent and on that of the 4-substituent in the aryl ring of the arylnitrones. This work provides a novel synthetic route to important intermediates: 2-aminophenols, 2-chloroanilines and 3-chloroanilines which are important industrial intermediates for pharmaceutical products (API), for azo-dye ingredients and for agricultural products.