IMPROVED PROCESS FOR THE PREPARATION OF STABLE NITROXYL RADICALS

摘要

Process for the preparation of stable nitroxyl radicals (I) starting from N-benzylphthalimide in two steps. In the first step, the intermediate N-benzyl-1, 1, 3, 3-tetra- alkylisoindoline is prepared by treatment with a Grignard reagent, prepared in methyl-tert-butyl ether, of N- benzylphthalimide, obtained in the same reaction environ - ment starting from phthalic anhydride and benzylamine. In the second step, the N-benzyl-1, 1, 3 , 3-tetra- alkylisoindoline is transformed into the nitroxyl radical by hydrogenolysis and subsequent oxidation with hydrogen peroxide in the presence of a catalyst selected from acids and salts of polymolybdic or polytungstic acids.