Todd A. Davis
Assistant Professor of Chemistry
Postdoctoral Studies, 2004-2007
Vanderbilt University, Advisor: Ned Porter
Ph.D. Organic Chemistry, 2004 Texas Tech University, Advisor: Bob Flowers
B.S. Chemistry
Grand Valley State University
| Research Area: | Organic, Medicinal, Environmental, and Analytical Chemistry |
| Student Experience required for research: | Chem. 301 and Chem. 302 |
| Student Experience gained from research: | Organic Synthesis, Mechanistic Investigation, and Instrumentation (NMR, GC, GC-MS, HPLC, and HPLC-MS-MS) |
| Ideal Preparation for: | Careers in the Pharmaceutical and Chemical Industries, Graduate and Professional School |
Research Description:
1.) Utilizing Fluorine to Direct Stereoselective Synthesis :
The introduction of fluorine to organic molecules can have a profound influence on biological activity. Recently, there has been a significant increase in the number of fluorinated drug candidates in Phase II and III clinical trials. Due to the heightened interest in fluorinated drug candidates, our laboratory has focused on developing methods for the preparation of fluoro-organics in high yield and stereoselectivity. The methods that are being developed will provide medicinal/pharmaceutical chemists with new tools for the synthesis of fluorine containing molecules with potential biological activity.
Recently, our lab has developed a stereoselective reduction of α-fluoroimines using trichlorosilane (Cl3SiH) as the reductant. It has been shown that this reaction is highly efficient proceeding in high yields and in select cases complete stereocontrol. It is believed that the high stereoselectivity is due to the reaction being under chelation control in which both the nitrogen and fluorine are required to activate silicon (Scheme 1). We are currently expanding on these methods by developing stereoselective nucleophilic addition reactions to α-fluorinated carbonyls (ketones and imines) utilizing a variety of organosilanes.
2.) Designing Polymer Flocculants for the Removal and Recycling of Inorganic Phosphate
Eutrophication is a process in which increased chemical nutrients cause unnatural aging (greening) of waterways. This unnatural aging of waterways forms algal blooms depleting the oxygen uptake in water causing serious risks to the ecosystem. The cause of these increased chemical nutrients can arise from water runoff, over fertilization, or sewage. One of the leading chemical contaminants in the eutrophication process is inorganic phosphates.
In this project, we are designing molecular hosts that can be synthetically incorporated into a polymer flocculant as a potential means for the removal and recycling of inorganic phosphate from contaminated water sources. Flocculants are polymers that are soluble in bulk solvents; however, in the presence of charged solid materials aggregate and precipitate out of solution. It is our intention that derivitization of a polymer flocculant with a phosphate trapping group will be an effective means for the removal of inorganic phosphate from wastewater. Our trapping groups are based on the strong hydrogen bonding interaction between thiourea and inorganic phosphate (Scheme 2).
Currently, we have tested our first generation polymer flocculant and have discovered that 34% of the total inorganic phosphate is removed under optimum conditions. Although this figure is still low, it is three times more efficient than the commercially available polymer flocculant (Magnifloc). Future endeavors will examine the ability to incorporate a third hydrogen binding site, investigate the role of pH, and extend this to examine the removal of pesticides.
Recent Publications:
- “Modifying Polymer Flocculants for the Removal of Inorganic Phosphate from Water” Goebel T. S.; McInnes, K. J.; Senseman S. A.; Lascano, R. J.; Marchand, l. S.; Davis, T. A. Tetrahedron Lett. 2011, 52, 5241-5244.
- “Highly Efficient Diastereoselective Reduction of α-Fluoroimines” Malamakal, R.M.; Hess, W.R.; Davis, T.A. Org. Lett. 2010, 12, 2186-2189.
- “Development of Novel LC/MS/MS Methodologies for the Quantification of Peroxidation Products Derived from Arachidonic Acid” Yin, H.; Davis, T.A.; Porter, N.A. Methods Molecular Biology 2010, 610, 375-386.
- “Rate Constants for Peroxidation of Polyunsaturated Fatty Acids and Sterols in Solution and in Liposomes” Xu, L.; Davis, T. A.; Porter, N. A. J. Am. Chem. Soc. 2009, 131, 13037-13044.
- “In vivo and in vitro Lipid Peroxidation of Arachidonate Esters: The Effect of Fish Oil w-3 Lipids on Product Distribution” Davis, T.A.; Gao, L.; Yin, H.; Morrow, J. D.; Porter, N.A. J. Am. Chem .Soc. 2006, 128, 14897-14904.
- “Chelation-Controlled Reductions of α-Fluoroketones” Mohanta, P. K.; Davis, T. A.; Gooch, J. R.; Flowers, R. A., II J. Am Chem. Soc. 2005, 127, 11896-11897.
- “Reduction of β-Hydroxyketones by SmI2/Et3N/H2O” Davis, T. A.; Chopade, P.; Flowers, R. A., II. Org. Lett. 2005, 7, 119-122.
- “Solvent Dependent Diastereoselectivities in Reductions of β-Hydroxyketones by SmI2” Chopade, P.; Davis, T.A.; Prasad, E.; Flowers, R.A., II Org. Lett. 2004, 6, 2685-2688.
- “Molecular Recognition of Heavy Metals by Polymer Supported Carbohydrates.” Todd A. Davis and Robert Smart, 1999 McNair Scholars Summer Research Journal.