1H and 13C NMR spectral studies of conformation of some N-(2-pyridinyl)-3-pyridinecarboxamides

Singh, Netai C and Sathyanarayana, DN (1998) 1H and 13C NMR spectral studies of conformation of some N-(2-pyridinyl)-3-pyridinecarboxamides. In: Journal of Molecular Structure, 449 (1). pp. 91-98.

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Abstract

The 1H and 13C NMR spectra of N-(2-pyridinyl)-, N-(4-methyl2-pyridinyl)-, and N-(6-methyl-2-pyridinyl)-3-pyridine-carboxamides (1�3, respectively) and 3-pyridinecarboxamide (4) in different solvents have been analysed using COSY, HETCOR, chemical shift and coupling constant correlations. The conformations of 1�4 have been obtained by utilizing the NMR spectra, NOE experiments and MINDO/3 calculations. In dilute solutions, the 2-pyridyl ring is coplanar with the amide group while the 3-pyridyl ring is apparently not. Compounds 1�3 dimerize through cooperative hydrogen bonding in concentrated CDCl3 solution (approximately 0.1 M) and the structure of the dimer resembles some of the DNA base-pairs. Hydrogen bonding between N---H and the solvent molecules hinders dimerization in (CD3)2CO and CD3CN.

Item Type:	Journal Article
Publication:	Journal of Molecular Structure
Publisher:	Elsevier science
Additional Information:	Copyright of this article belongs to Elsevier science.
Keywords:	NMR spectroscopy;Molecular conformation;Hydrogen bonding; Association;Pyridinecarboxamides.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	09 Jun 2011 07:19
Last Modified:	09 Jun 2011 07:19
URI:	http://eprints.iisc.ac.in/id/eprint/38114

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