The reactivity of the halogenonaphthols towards nucleophiles. Part II. The kinetics and mechanisms of the reactions of 1-halogeno-2-naphthols with anilines

Abstract

1-Halogeno-2-naphthols react with the X-substituted anilines yielding normal substitution products. The ‘abnormal’ activating power of the OH-group in position 2 is related to the presence of tautomeric keto-enolic equilibrium wherein the hydrogen atom migrates from the hydroxylic oxygen atom to position 1, which carbon atom becomes tetrahedral. The reactive species is the keto-form which is an α-halogeno-oxo-derivative.The second-order kinetic constants found experimentally decrease with increase of initial concentration of the reactant amine. This is consistent with the presence of both a first-order and a second-order process. The effects of structural changes in the nucleophile and in the leaving group indicate that the second-order process is similar to an SN2 process while the first-order process has an SN1 mechanism.