Z. Dega‐Szafran, E. Dulewicz, M. Szafran
Jul 3, 2006
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0
Influential Citations
4
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract Conformations of two 1-carbethoxymethyl-4-hydroxy-1-methylpiperidinium chlorides ( 1α and 1β ), 4-hydroxy-1-methylpiperidine betaine hydrochlorides ( 2α and 2β ), and 4-hydroxy-1-methylpiperidine betaine inner salts ( 3α and 3β ), having a hydroxyl group at axial (α) or equatorial (β) positions, have been studied by the 1 H and 13 C NMR spectroscopy. The signals attributed to the equatorial and axial protons at C-2,6 have been found to differentiate the appropriate conformers. The NOE effect has been used to assign the equatorial and axial protons at C-3,5. The C-2,6 carbon atoms in the α-conformers have been shown to be shielded by the axial 4-hydroxyl group due to the γ-gauche substituent effect. The magnetic isotropic shielding tensors have been calculated by GIAO/B3LYP/6-31G(d,p) method and correlated with the experimental chemical shifts.