Theoretical studies on the conformations of cyclitols in solution

Abstract

Theσ-charges on various atoms in inositols have been computed by using the MO-LCAO method of Del Re. The potential and free energies of seven inositols in the normal (N) and alternative (A) conformations have also been calculated. Minimization of the energies of these conformations have been studied by suitably tilting the axial hydroxyl groups. Tilts of about 1.5° are predicted for the hydroxyl groups involved in syn-axial interactions, in the minimum energy conformations. As in aldopyranoses, in inositols also conformations which have fewer axial hydroxyl groups are favoured. The present calculations predict the order of preference ofneo-, allo- andmuco-inositols in the equilibrium mixture, in accordance with the experimental results.