Someshwar D. Dindulkar, P. Parthiban, V. Puranik
Mar 29, 2011
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Influential Citations
7
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Journal
Journal of Molecular Structure
Abstract
Abstract A series of thirteen 1-benzyl-3-alkyl-2,6-diarylpiperidin-4-ones 14–26 were conveniently synthesized in high yields 87–92%. In order to find the impact on piperidone stereochemistry, beside the N-benzylation, methyl/ethyl/isopropyl groups at C-3 and halo/alkyl/alkoxy/benzyloxy groups on the phenyl rings at C-2/C-6 were introduced. All the synthesized compounds were characterized by mass, 1H and 13C NMR spectral studies. Of them, the 1-benzyl-3-ethyl-2,6-diphenylpiperidin-4-one 22 was completely characterized by 2D NMR techniques such as 1H 1H COSY, 1H 13C COSY and NOESY to assign the signals, unambiguously. The proton coupling constants and NOE correlations provided the complete stereochemistry of 22, which is further witnessed by its single-crystal XRD analysis. The NMR and XRD studies revealed that the compound 22 exists in a chair conformation with equatorial orientation of all the substituents in both solution and solid states. On the basis of their vicinal coupling constants, the chair conformation with equatorial orientation of the substituents at C-2, C-3, C-6 and N is proposed for all compounds 14–26; moreover, a considerable population of boat conformation also suggested for the compound 26 along with the predominant chair conformation, in solution.