Conformation of monobenzyl ethers of piperidyl-containing acetylenic glycols, according to13C NMR spectroscopic data

Abstract

In the13C NMR spectra of individual (β)- and (γ)-epimers (through the C4 carbon atom of the six-membered ring) of monobenzyl ethers of piperidyl-containing acetylenic glycols, it has been found that the chemical shifts of the epimers differ by as much as 3 ppm for the C2, C4, and C6 carbon atoms. The most probable conformations of the epimers are suggested, including intramolecular hydrogen bonds between the proton of the OH group and the unshared electron pair of the nitrogen.