Elucidating the Origin of Conformational Energy Differences in Substituted 1,3-Dioxanes: A Combined Theoretical and Experimental Study
- 1 January 1996
- journal article
- research article
- Published by American Chemical Society (ACS) in The Journal of Organic Chemistry
- Vol. 61 (11) , 3662-3668
- https://doi.org/10.1021/jo951918p
Abstract
13C NMR spectroscopy, ab initio quantum mechanics, and molecular mechanics have been used to investigate the trans-4-(trifluoromethyl)-2,2,6-trimethyl-1,3-dioxane chair/twist-boat equilibrium. The molecular mechanics calculations were based upon the MM3 and AMBER force fields. A 6-31G basis set was used for the ab initio calculations, and MP2 correlation corrections were applied. Both the ab initio and AMBER molecular mechanics calculations are consistent with the (13)C NMR chemical shift differences for the trans-4-(trifluoromethyl)-2,2,6-trimethyl-1,3-dioxane conformers. The predicted chair to twist-boat equilibrium suggested by the MM3 calculations is not consistent with the experimental data. These results support the suggestion by Howard et al. (Howard, A. E.; Cieplak, P.; Kollman, P. A. J. Comput.Chem. 1995, 16, 243-261) on the critical role of electrostatic interactions in determining the chair/twist-boat equilibrium.Keywords
This publication has 11 references indexed in Scilit:
- A Second Generation Force Field for the Simulation of Proteins, Nucleic Acids, and Organic MoleculesJournal of the American Chemical Society, 1995
- A molecular mechanical model that reproduces the relative energies for chair and twist-boat conformations of 1,3-dioxanesJournal of Computational Chemistry, 1995
- Application of RESP charges to calculate conformational energies, hydrogen bond energies, and free energies of solvationJournal of the American Chemical Society, 1993
- A well-behaved electrostatic potential based method using charge restraints for deriving atomic charges: the RESP modelThe Journal of Physical Chemistry, 1993
- Derivation of fluorine and hydrogen atom parameters using liquid simulationsJournal of Computational Chemistry, 1992
- Macromodel—an integrated software system for modeling organic and bioorganic molecules using molecular mechanicsJournal of Computational Chemistry, 1990
- An all atom force field for simulations of proteins and nucleic acidsJournal of Computational Chemistry, 1986
- An approach to computing electrostatic charges for moleculesJournal of Computational Chemistry, 1984
- Biosynthetic origin of the carbon skeleton and oxygen atoms of nargenicin A1Journal of the American Chemical Society, 1984
- Conformational analysis. 130. MM2. A hydrocarbon force field utilizing V1 and V2 torsional termsJournal of the American Chemical Society, 1977