Synthesis and molecular structure of the 1-phenyl-2-(2-pyridyl)ethanol intermediate obtained from the condensation reaction of 2-picoline and benzaldehyde

The 1-phenyl-2-(α-pyridyl)ethanol [or 1-phenyl-2-(2-pyridyl)ethanol] compound was obtained from the Knoevenagel condensation reaction between 2-methylpyridine with benzaldehyde without catalyst or solvent. The compound was characterized by IR, 1H-NMR, and by single crystal X-ray diffraction. The X-ray structure clearly revealed that the compound crystallizes in a monoclinic system with centrosymmetric space group, P21/c, with Z′ = 1. The unit cell dimensions are a = 5.2481(3), b = 8.2862(4), c = 23.8498(14) A, and β = 96.761(5)°. The crystal structure showed the formation of one intermolecular hydrogen bond O–H···N between the oxygen atom of the O–H and the nitrogen atom of the pyridine group of the adjacent molecule. The crystallography data gave evidence that the intermediate compound is a new stable 1-phenyl-2-(2-pyridyl)ethanol intermediate which presents an interesting relationship between stability and hydrogen bonds formation in the structure for obtaining similar compounds that have been proposed in the literature. Also, it is shown that it is just before the dehydration process which yields the trans double bond of the 1-phenyl-2-(2-pyridyl)ethene.