Di-n-substituted 2-halogenoethylamines. Part VII. NN-dialkyl-2-1′- or -2′-naphthyl derivatives, and some miscellaneous related compounds: synthesis, reactivity, and pharmacology

A series of compounds Ar·CRBr·CH₃·NR′ R″,HBr has been prepared with Ar = 1- or 2-naphthyl, R = H, R′ = R″ = alkyl, and with Ar = Ph or 1-naphthyl, R = Me, Et, or Prⁱ, and R′ = R″ = Me; the corresponding tertiary alcohols have been prepared by the action of an alkylmagnesium halide on an aryl dimethylaminomethyl ketone. The hydrobromides of NN-dimethyl-2-bromo-4- phenylbutylamine, of NN-dimethyl-2-bromo-4-phenylbut-3-enylamine, and of the corresponding piperidino-compounds have also been prepared. From the product of reaction of phosphorus tribromide with NN-dimethyl-2-hydroxy-2,2- diphenylethylamine only dimethylamine hydrobromide was isolated. The action of phosphorus tribromide on (±)-cis- or (±)-trans-NN-dimethyl-2- hydroxycyclohexylamine gave one and the same substance, which is believed to be a mixture of about 37% of the corresponding (+)-trans-bromo-compound, and about 63% of the (±)-cis-bromo-compound. (±) -cis- and (±)-trans-NN-Diniethyl-2-hydroxy-2-phenylcyclohexy lamine have been prepared and characterised, but with phosphorus tribromide they yielded only uncrystallisable products. The solvolysis in 1:1 aqueous acetone at 31-0° of some of the bromoamines has been studied. Compounds containing a naphthyl group or a tertiary arylalkyl bromide group differ from NN-dimethyl-β- bromophenethylamine in yielding no ethyleniminium ion, despite a rapid initial release of bromide ion. These observations are interpreted in terms of a reaction scheme involving a carbonium ion derived from the ethyleniminium ion, and the influence of its structure on its stability and reactivity towards nucleophiles. The pharmacological properties of some of the compounds are briefly discussed.