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

Singha, Netai C and Sathyanarayana, DN (1998) $^1H$ and $^{13}C$ 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 $^IH$ and $^{13}C$ 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 con-centrated $CDCI_3$ 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 $(CD_3)_2CO$ and $CD_3CN$.

Item Type:	Journal Article
Publication:	Journal of Molecular Structure
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Esevier.
Keywords:	NMR spectroscopy;Molecular conformation;Hydrogen bonding;Association;Pyridinecarboxamides
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	17 Jan 2007
Last Modified:	19 Sep 2010 04:34
URI:	http://eprints.iisc.ac.in/id/eprint/9522

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