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Conformational Analysis of Furanose Ring Systems: Experimental and Theoretical Studies

Houseknecht, Justin B
http://rave.ohiolink.edu/etdc/view?acc_num=osu1040404808

Abstract Details

2003, Doctor of Philosophy, Ohio State University, Chemistry.
Experimental and theoretical methods have been used to determine the conformational preferences of substituted furanose ring systems. These studies have provided an improved understanding of the conformations adopted by specific furanose rings and the factors affecting furanose ring conformation. In addition, established methods for probing furanose ring conformation have been improved and new methods have been developed. Synthetic organic chemistry has been used to prepare a series of oligosaccharides in which a central furanose ring was covalently locked or electronically biased toward a particular conformation. High-magnetic field nuclear magnetic resonance (NMR) was used to determine the 3JHH values for each furanose ring within the prepared oligosaccharides. These 3JHH values were used to determine that the conformational preferences of a furanose ring are determined by its substituents, not the conformation of adjacent furanose rings. The first reported study of furanose ring conformation in a model of aqueous solution and a new method for comparing theoretical and experimental conformational data is reproduced. The conformational preferences of methyl 3-O-methyl-a-D-arabinofuranoside were studied by sampling the conformational space with a Systematic Pseudo Monte Carlo (SPMC) search linked to the AMBER* force field. Subsets of the resulting conformers were then subjected to further ab initio and DFT optimizations in both the gas phase and in models for aqueous solution. The procedure used to determine furanose ring conformational preferences from 3JH,H data was improved by determining more accurate values correlating endocyclic and exocyclic dihedral angles for all possible substituent patterns. The previous approximation of these correlation values was found to be inadequate, and improved values were determined from geometries optimized with density functional theory. These same geometries were also used to develop a Karplus equation specific for the 3JC1,H4 coupling in aldopentofuranosides. Measurement of this coupling constant in a series of aldopentofuranosides and use of the new Karplus equation provided a clearer understanding of the less well studied aldopentofuranosides. Finally, these geometries were also used to study the conformational preferences of the aldopentofuranosides in the gaseous and solution phases.
Todd Lowary (Advisor)
529 p.
Chemistry, Organic
carbohydrate; furanose; conformation; coupling constant

Recommended Citations

Citations

  • Houseknecht, J. B. (2003). Conformational Analysis of Furanose Ring Systems: Experimental and Theoretical Studies [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1040404808

    APA Style (7th edition)

  • Houseknecht, Justin. Conformational Analysis of Furanose Ring Systems: Experimental and Theoretical Studies. 2003. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1040404808.

    MLA Style (8th edition)

  • Houseknecht, Justin. "Conformational Analysis of Furanose Ring Systems: Experimental and Theoretical Studies." Doctoral dissertation, Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1040404808

    Chicago Manual of Style (17th edition)

osu1040404808
654
© 2002, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.