Persistent Nitrogen-centered Free Radicals, N-(Arylthio)-3,5-di-t-butylphenylaminyls. The Reactions with Phenols

The reactions of N-(4-chlorophenylthio)-3,5-di-t-butylphenylaminyl (1) with phenols were examined. The reaction with 2,6-dimethyl- and di-t-butylphenols gave 2,6-dimethyl- and di-t-butyl-p-benzoquinone 3,5-di-t-butylphenylimines, respectively, in excellent yields. In the reaction with unsubstituted phenol, 2,6-bis[N-(4-chlorophenylthio)-3,5-di-t-butylphenylamino]-p-benzoquinone 3,5-di-t-butylphenylimine was obtained in 32–56% yields. On the other hand, the reactions with p-substituted phenols such as p-cresol, p-t-butylphenol, and 2,4-di-t-butylphenol, gave phenols which were substituted by 1 at the ortho-positions to the OH group. Furthermore, the reactions with o-cresol, 2,6-di-t-butyl-p-cresol, and 1-naphthol were examined. On the basis of these results, plausible mechanisms for the reactions are presented.