The rates of oxidation of several substituted benzyldimethylamines by bromine in 50% aqueous acetic acid have been determined spectrophotometrically. Electron-withdrawing substituents decrease the rate of reaction with the Hammett p value being -0.95. The reaction is subject to general base catalysis and substitution of deuterium in the a-position decreases the rate of reaction by approximately 30%, thus indicating that the a-C-H bond is cleaved in the slow step of the reaction. All results are consistent with a mechanism which involves, in the rate determining step, loss of an a-hydrogen atom as a proton with concomitant transfer of electrons from nitrogen to the oxidant.

The basicities of a series of substituted benzyldimethylamines have been determined potentiometrically in 50% (by weight) aqueous methanol. An excellent Hammett correlation (ρ = −1.38) is obtained. The larger value of ρ in aqueous methanol as compared to water (−1.14) is interpreted in terms of a greater capability of water to solvate ammonium ions, thus suppressing the stabilizing or destabilizing effect of ring substituents.

No abstract

No abstract