Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 28, 2003
Publication Date: June 12, 2003
Citation: APPELL, M.D., MOMANY, F.A., WILLETT, J.L. B3LYP/6-311++G** STUDY OF THE BOAT FORMS OF ALPHA- AND BETA-GLUCOPYRANOSE AND ITS MONOSUBSTITUTED EPIMERS.MEETING ABSTRACT. 2003. Abstract p. 100. Technical Abstract: Density functional/ab initio methods were applied to gradient geometry optimize the gg, gt, and tg rotamers of the boat forms of glucopyranose and its epimers in vacuo. Preliminary optimization was carried out at the B3LYP/6-31+G* level and further optimization was carried out at the B3LYP/6-311++G** level of theory. Comparisons of the boat conformers of glucopyranose with epimer boat forms will be discussed. Many epimer conformers retained their initial boat forms following geometry/energy optimization, however some did not. For the gg and gt rotamers of a-glucopyranose, there exists a transition without barrier from the B3, 0 boat tot he 4C1 chair. However, the tg twist-boat of a-glucopyranose and all the rotamers of B-glucopyranose in the B3, 0 boat retained the boat conformation upon energy/geometry optimization. All of the B-mannopyranose rotamers considered have a transition without barrier from the 3, OB boat to the twist-boat form. Only the tg and a selected gg 3, OB form of B-allopyranose underwent a transition without barrier to the twist-boat conformer, while the other hydroxymethyl conformers remained near the starting boat conformation.