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United States Department of Agriculture

Agricultural Research Service

Title: Density Functional Study of the Chair Forms of Alpha and Beta-D-Allopyranose at the B3lyp/6-311++g** Level.

Authors
item Appell, Michael
item Willett, Julious
item Momany, Frank

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 7, 2004
Publication Date: June 17, 2004
Citation: Appell, M.D., Willett, J.L., Momany, F.A. Density functional study of the chair forms of alpha- and beta-d-allopyranose at the b3lyp/6-311++g** level. Midwest Theoretical Chemistry Conference. 2004. {abstract} p. 16.

Technical Abstract: Geometry optimizations were carried out on the 4C1 and 1C4 chair conformations of allopyranose at the B3LYP/6-311++G** level of theory. These density functional calculations will be compared to those of glucopyranose as a means to identify the effects of epimerization at the C-3 position. The alph- and Beta-anomers of the gg, gt, and tg rotamer conformations were investigated, as well as the clockwise and counterclockwise hydroxyl orientations. The 4C1 chair conformations of allopyranose are between 0.4-2.8 kcal/mol higher in energy than the lowest energy glucopyranose structure identified (alpha-gt-4C1 chair). The lowest energy allopyranose structure found is the Beta-gg-4C1 chair conformation with the hydroxyls in the counterclockwise orientation. The 1C4 chair conformations of allopyranose are 2.4-6.8 kcal/mol higher in energy than the Beta-gg-4C1 form. All of the 1C4 chair conformations of allopyranose in this investigation have been found to be lower in overall energy than their glucopyranose counterparts.

Last Modified: 9/22/2014
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