Halogenation of N-substituted p-quinone monoimines and p-quinone monooxime esrers: XI. Synthesis and halogenation of 4-[aryl(alkyl)aminocarbonyl-oxyimino]cyclohexa-2,5-dien-1-ones

4-[Aryl(alkyl)aminocarbonyloxyimino]cyclohexa-2,5-dien-1-ones were synthesized by treatment of various substituted p-quinone monooximes with aryl isocyanates. The selectivity in the halogenation of the obtained p-quinone monooxime esters depended on the substrate structure and was either completely (syn addition) or partly regioselective (syn or anti addition). In all cases, the effect of steric factor was crucial, and the reaction was accompanied by halogenation of the aryl fragment.