Comparative rates of nucleophilic substitution by thiophenoxide anion at axial and equatorial N-alkyl groups in cyclic quaternary salts

Abstract

Study of the degradation of isomeric N-ethyl-N-methyltropanium iodides, and of N-methyl [¹⁴C]methiodides derived from 2-methyl- and 4-phenyl-piperidines, tropane, camphidine, and trans-decahydroquinoline with sodium thiophenoxide in hot digol has for most of the reactions confirmed the previous conclusion that the nucleophilic displacement removes an alkyl group more readily when this is in the orientation it preferentially adopts during its introduction in a quaternisation of the tertiary base.