NITROXIDE RADICALS .6. STABILITY OF META- AND PARA-ALKYL SUBSTITUTED PHENYL-T-BUTYLNITROXIDES

Aryl-t-butylnitroxides with primary or secondary para-alkyl substituents disproportionate during isolation to the parent hydroxy lamines and the corresponding quinone methide imine N-oxides. These usually react further to yield dimeric, trimeric, or polymeric hydroxylamines, some of which fragment to give amines and p-acylphenyl-t-butylhydroxylamines. Aryl-t-butylnitroxides with meta-alkyl substituents, which hinder attack at the para-position, or with tertiary alkyl para-substituents are sufficiently stable to be isolated.