Maleimide and N-substituted maleimides are arylated by diazonium salts in aqueous acetone at pH 3 in the presence of cupric chloride (Meerwein reaction). a-Arylmaleimides are formed in 20-55% yield. The yield is lowest with unsubstituted phenyl and it increases with the introduction of either electron-attracting or electron-releasing substituents into the para position. The arylmaleimides can be hydrolyzed readily and recyclized to arylmaleic ...
