O-Alkylation of N-phenylhydroxylamine in dimethyl sulfoxide with methylarenesulfonates

The methylation of N-phenylhydroxylamine (NPHA) with methylarenesulfonates in DMSO gives alkylation of the O atom in contrast to methylation in methanol where N alkylation occurs. The Hammett rho values indicate that alkylations with N-methylanilines and NPHAs both involve the N atom. The NPHAs show ''nominal alpha-effects'' but involve comparison of N atoms with O atoms. The reactivity of the principle component, the zwitterion I, is examined with leaving group studies and comparison with benzyl alkoxide reactivity.