Synthesis, Characterization And Structural Studies Of Medicinally Important Pyridine Derivatives
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Date
2016-04
Authors
Farhadikoutenaei, Abbas
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Publisher
Universiti Sains Malaysia
Abstract
In this work, twenty novel salts of 2-amino-5-methylpyridine and 2-amino-4-methylpyrimidine with aromatic and aliphatic carboxylic acids have been investigated using spectroscopic methods such as powder and single crystal X-ray crystallography, infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy. In all the compounds, the protonated N atom and the 2-amino group of the cations are hydrogen bonded to the carboxylate O atoms of the anions via a pair of N‒H···O and N+‒H···O¯ hydrogen bonds, forming an R2/2 (8) ring motifs. The refinement of the structures indicates that fourteen of the compounds crystallized in the monoclinic space group, four in triclinic and one each in tetragonal and orthorhombic. In this research, the formation of the new crystal is shown by a good consistency between the powder diffraction pattern of the bulk samples and the simulated patterns obtained from single X-ray diffraction data and they were different from the powder pattern of the starting materials. In all the compounds, the combination bond of the N‒H in pyridine and pyrimidine was shown by the peaks related to stretching frequencies of 1877 to 2044 cm‒1 and the ion of carboxylate is characterized by asymmetrical and symmetrical stretching frequencies in the region of 1550‒1650 and about 1400 cm‾1, respectively. The proton transfer and the skeleton for all the compounds were also analyzed by 1H NMR and 13C NMR.
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Spectroscopic