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.