O-ALKYLATION OF N-PHENYLHYDROXYLAMINE IN DIMETHYL-SULFOXIDE WITH METHYLARENESULFONATES

The methylation of N-phenylhydroxylamine (NPHA) with methylarenesulfon ates in DMSO gives alkylation of the O atom in contrast to methylation in methanol where N alkylation occurs. The Hammett rho values indicat e 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, th e zwitterion I, is examined with leaving group studies and comparison with benzyl alkoxide reactivity.