Rationalizing nuclear overhauser effect data for compounds adopting multiple-solution conformations
✍ Scribed by Mark J. Forster; Barbara Mulloy
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 540 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0192-8651
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✦ Synopsis
Abstract
An algorithm is described for refining the populations of a set of multiple‐solution conformers using experimental nuclear Overhauser effects (nOes). The method is based upon representing the effective relaxation matrix for the set of interconverting proposed conformers as a linear combination of relaxation matrices (LCORMs) due to each conformer. The conformer population derivative of the nOe is derived from a Taylor series expression for the calculated nOe. This derivative may then be used in a standard nonlinear least‐squares refinement procedure. The LCORM nOe procedure is tested using a monosaccharide system, 1‐O‐methyl‐α‐L‐iduronate, that is known to exhibit conformational variability. The measured nOes for this system are used to refine the populations of a set of three static conformers, namely, the ^1^C~4~, ^4^C~1~, and ^2^S~0~ ring conformers. The populations thus derived are compared to those previously obtained using nuclear magnetic resonance proton‐proton coupling constant information. Two possible extensions to the method are discussed: The first uses combined nOe and coupling constant data while the second removes the restrictions that the conformers used for fitting be rigid entities. © 1994 by John Wiley & Sons, Inc.