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Conformational analyses of 2,3-dihydroxypropanoic acid as a function of solvent and ionization state as determined by NMR spectroscopy

Drake, Michael D. and Harsha, Alex K. and Terterov, Sergei and Roberts, John D. (2006) Conformational analyses of 2,3-dihydroxypropanoic acid as a function of solvent and ionization state as determined by NMR spectroscopy. Magnetic Resonance in Chemistry, 44 (3). pp. 210-219. ISSN 0749-1581. http://resolver.caltech.edu/CaltechAUTHORS:20150930-125951835

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Abstract

Vicinal ^1H-^1H coupling constants were used to determine the conformational preferences of 2,3-dihydroxypropanoic acid (1) (DL-glyceric acid) in various solvents and its different carboxyl ionization states. The stereospecific assignments of J_(12) and J_(13) were confirmed through the point-group substitution of the C-3 hydrogen with deuterium, yielding rac-(2SR,3RS)-[3^(-2)H]-1, and the observation of only J_(13) in the ^1H NMR spectra. While hydrogen bonding and steric strain may be expected to drive the conformational equilibrium, their role is overshadowed by a profound gauche effect between the vicinal hydroxyl groups that mimics other substituted ethanes, such as 1,2-ethanediol and 1,2-difluoroethane. At low pH, the conformational equilibrium is heavily weighted toward the gauche-hydroxyl rotamers with a range of 81% in DMSO-d_6 to 92% in tert-butyl alcohol-d_(10). At high pH, the equilibrium exhibits a larger dependence upon the polarity and solvating capability of the medium, although the gauche effect still dominates in D_2O, 1,4-dioxane-d_8, methanol-d_4, and ethanol-d_6 (96, 89, 85, and 83% gauche-hydroxyls respectively). The observed preference for the gauche-hydroxyl rotamers is believed to stem primarily from hyperconjugative σC-H → σ^*C-OH interactions.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1002/mrc.1758DOIArticle
http://onlinelibrary.wiley.com/doi/10.1002/mrc.1758/abstractPublisherArticle
http://www.ncbi.nlm.nih.gov/pubmed/16477695PubMed CentralArticle
Additional Information:© 2006 John Wiley & Sons, Ltd. Received 14 October 2005; Accepted 26 October 2005. Article first published online: 14 Feb 2006. Acknowledgement is made to the donors of the Petroleum Research Fund administered by the American Chemical Society for support of this research. We are also deeply indebted to the National Science Foundation (CHE-0104273), the Summer Undergraduate Research Fellowship Program (SURF) at the California Institute of Technology, the Senior Scientist Mentor Program of the Camille and Henry Dreyfus Foundation, the E. I. DuPont Company, Merck, Dr and Mrs Chester M. McCloskey and Edith M. Roberts for their helpful financial assistance.
Funders:
Funding AgencyGrant Number
American Chemical Society Petroleum Research FundUNSPECIFIED
NSFCHE-0104273
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
Camille and Henry Dreyfus FoundationUNSPECIFIED
E. I. DuPont CompanyUNSPECIFIED
MerckUNSPECIFIED
Dr and Mrs Chester M. McCloskeyUNSPECIFIED
Edith M. RobertsUNSPECIFIED
Subject Keywords:NMR; ^1H NMR; conformational analysis; 2,3-dihydroxypropanoic acid; glyceric acid; solvent effects; gauche effect; hyperconjugation; glyceric acid deuteriation
Record Number:CaltechAUTHORS:20150930-125951835
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20150930-125951835
Official Citation:Drake, M. D., Harsha, A. K., Terterov, S. and Roberts, J. D. (2006), Conformational analyses of 2,3-dihydroxypropanoic acid as a function of solvent and ionization state as determined by NMR spectroscopy. Magn. Reson. Chem., 44: 210–219. doi: 10.1002/mrc.1758
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:60612
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:01 Oct 2015 17:23
Last Modified:01 Oct 2015 17:23

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