Unexpected crystallization and X-ray crystal structure of racemic 1-phenyl-2-(4-pyridyl)ethanol intermediate

We have isolated, by crystallization, the intermediate, 1-phenyl-2-(4-pyrid yl)ethanol, from the condensation reaction of 4-methylpyridine with benzald ehyde in which the aim was to obtain the model compound 4-styrylpyridine in absence of a condensing agent. Single crystal X-ray analysis shows the for mation of an intermolecular hydrogen bond O-H . . .N between the nitrogen a tom of a pyridine group and the oxygen atom of the OH of the neighboring mo lecule, which helps to stabilize the crystal structure. Crystal structure d etermination clearly revealed that the solid is chiral and racemic, as expe cted. The title compound crystallizes in an orthorhombic system with a spac e group Pna2(1) with two pairs of R and S enantiomers in each crystal cell (a = 15.591(1) Angstrom, b = 12.691(1) Angstrom, and c = 5589(1) Angstrom). Spectroscopic NMR data gave evidence that the isolated compound is actuall y the alcohol just before the dehydration process that yields the double bo nd of the 4-styrylpyridine.