Infrared-spectral studies on the orientation of the lone pairs in piperidine derivatives

Abstract

The infrared spectra of stereoisomers of several piperidines and their N-methyl derivatives in carbon tetrachloride have been measured in the region of 3020 to 2500 cm−1. The estimated intensities (A) of their Bohlmann bands have been analyzed, provided that Formula (1) concerning the intensity defined in the text holds for the compounds examined. The result indicates that piperidine exists mainly, but not exclusively, in the conformation with the lone pair axial.