Conformational study of some N-Nitroso-2r, 6c-diphenylpiperidin-4-one oximes using NMR spectra
作者:G. Muthukumaran、K. Pandiarajan
DOI:10.1016/j.molstruc.2018.11.068
日期:2019.3
Stereochemistry of N-nitroso-2r,6c-diphenylpiperidin-4-one oxime (1), N nitroso-3t-methyl-2r,6c-diphenylpiperidin-4-one oxime (2), N nitroso-3t-isopropyl-2r,6c-diphenylpiperidin-4-one oxime (3), N- nitroso-3t-ethyl-2r,6c-diphenylpiperidin-4-one oxime (4) has been studied using H-1, C-13 and twodimensional NMR spectra. Analysis of the spectral data shows that in 2, 3 and 4 the NOH group is anti to the alkyl group at C-3. All the four compounds seem to exist largely in boat conformations with one phenyl group in the flagpole position. Analysis on the reported spectral data on N nitroso-2r,6c-diphenylpiperidin-4-ones suggests that these compounds also largely exist in boat conformations with one phenyl group in the flagpole position. Chair conformation with axial phenyl groups may contribute to some extent. The relative populations of the boat and chair conformations have been supported by the observed NOEs in their NOESY spectra. (C) 2018 Elsevier B.V. All rights reserved.