Synthesis and NMR study of the stereochemistry of r(2),c(6)-diaryl-c(3)chloropiperidin-4-ones

Abstract

r(2),c(6)-Diaryl-c(3)-chloropiperidin-4-ones have been obtained by the epimerization of r(2),c(6)-diaryl-t(3)chloropiperidin-4-ones by treatment with ammonia in DMF. The ¹H and ¹³C NMR spectra of these piperidones were measured in CDCl₃ at 360 and 90 MHz respectively and the chemical shifts assigned unambiguously employing one dimensional ¹H and ¹³C and two-dimensional H, H-COSY, C,H-COSY and NOESY NMR spectra. NMR spectroscopic parameters of the epimeric pair of chloropiperidones have been compared and the differences rationalized in terms of stereochemical features.