APPLICATION OF MOLECULAR MECHANICS TO THE STRUCTURE OF 1,6-ANHYDROPYRANOSES

Empirical force-field calculations have been applied to eight 1,6-anhydropyranoses, the crystal structures of which have been studied by single crystal X-ray, or neutron, diffraction analysis. The theoretical calculations reproduce closely the variations in conformation, between 1C4 and E0, which are observed for the pyranoid rings. The smaller conformational differences in the five-membered anhydro ring are not so well predicted. The calculated CC bond lengths agree with those observed within 1.2 pm. with one exception. The CO bond lengths show a larger deviation, 2.7 pm. The non-hydrogen atom valence angles agree within 1.9°. © 1979.