3,3-disubstituted piperidin-4-ones. Conformational analysis by NMR and circular dichroism methods

Abstract

Using ¹H and ¹³C NMR spectroscopy, we have established the conformational inhomogeneity of chiral 3,3-disubstituted piperidin-4-ones. The conformer with an equatorial methyl group on the C₍₃₎ atom predominates in the conformational equilibrium. For (1′S, 3S)-1-(1'-phenylethyl)-3-(2-cyanoethyl)- and 1,3-dimethylpiperidin-4-ones, we found ¹H NMR spectral parameters which may serve as criteria for conformational homogeneity of piperidin-4-one molecules. The conformational composition of the (3S)-enantiomers of 1,3-dimethyl-3-(2-cyanoethyl)- and 1,3-dimethyl-3-(2-carbomethyl)piperidin-4-ones was also estimated on the basis of theoretical analysis of the circular dichroism spectra in solvents of different polarities.

How to Cite
Gaidarova, E. L.; Aliev, A. É.; Chumakov, T. I.; Grishina, G. V. Chem. Heterocycl. Compd. 1994, 30, 800. [Khim. Geterotsikl. Soedin. 1994, 926.]

For this article in the English edition, see DOI https://doi.org/10.1007/BF01169637