Stereochemical transformations of some seven-membered pyridoxine dimethyl ketals

Abstract

According to the data of single crystal X-ray diffraction analysis and computational methods, the seven-membered rings of acylated pyridoxine acetonides have C 2 symmetry. Two stereochemical transformations in solutions, enantiotopomerization of P-, M-conformations with spiral chirality of twist-boat forms and diastereotopomerization of structures that differ in the configuration of the phenolic oxygen substituents, were revealed by dynamic 1H NMR spectroscopy. © 2007 Pleiades Publishing, Ltd