Halogenation of N-substituted para-quinone monoimine and para-quinone monooxime esters: V. Chlorination and bromination of N-arylsulfonyl-1,4-benzoquinone monoimines dialkyl-substituted in the quinoid ring

The direction of halogen addition to N-arylsulfonyl-1,4-benzoquinone monoimines dialkyl-substituted in the quinoid ring is governed by the steric factors: the size and position of the substituent, the halogen volume, and the position of the substituent at the nitrogen. The first stage of halogenation of N-arylsulfonyl-4-aminophenols with two alkyl substituents in the phenylsulfonyl ring largely occurs as electrophilic substitution.