Effect of Solvents on the Conformational Preferences of Oxy[bis(methylene)]bis[(1,3-dioxan-5-yl)methanol]

The conformational behavior of oxy[bis(methylene)]bis[(1,3-dioxan-5-yl)methanol] in various solvents was studied by NMR. According to the results of a 2D NOESY experiment, in С₆D₆ and CDCl₃ the compound prefers a bis(chair) form with diaxial hydroxymethyl groups, and in DMSO-d₆ and CD₃CN – the form with axial and equatorial hydroxymethy groups at С⁵ and С^5' atoms of the rings. The results of computer simulation of the conformational transformations of the studied diformal in these solvents at the DFT PBE/def2-SVP (approximation) are in complete agreement with the NMR data. It was shown that the optimal number of solvent molecules in the nearest solvation shell of oxy[bis(methylene)]bis[(1,3-dioxan-5-yl)methanol] varies from five to seven, depending on the nature of the solvent.