The Vapour-Phase Reaction of 2-Alkyltetrahydropyrans with Aniline over Alumina

Abstract

The vapour-phase reaction of 2-methyl-tetrahydropyran and 2-ethyltetrahydropyran with aniline over an activated alumina catalyst has been studied. The product, in each case, consisted of a mixture of an N-arylpiperidine, an N-arylpyrrolidine formed by ring contraction, and two N-alkenylanilines formed by ring opening. The structures of the nitrogen heterocyclic compounds were established by independent syntheses involving the reaction of the appropriate dibroinoalkane with aniline. The N-alkenylanilines were characterised by hydrogenation to known N-alkylanilines and by identification of the osonolysis products.