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Development of a Photochromic Nitroxyl Delivery System. David Spivey Mentor: Dr. Kevin P. Schultz Goucher College. Nitroxyl (HNO). HNO has been found to have pharmacological effects: Positive cardiac inotropy Vasodilation Inhibits breast cancer tumor growth
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Development of a Photochromic Nitroxyl Delivery System David Spivey Mentor: Dr. Kevin P. Schultz Goucher College
Nitroxyl (HNO) • HNO has been found to have pharmacological effects: • Positive cardiac inotropy • Vasodilation • Inhibits breast cancer tumor growth • Potential therapeutic agent for heart disease • Downside: highly unstable in physiological conditions
Current HNO Donors • A stable and controllable nitroxyl donor is needed to further study its therapeutic benefits and potential usefulness as a drug
Chromism • A process that induces a reversible color change in compounds • Types of chromism: • Photochromism - color change caused by light • Thermochromism - color change caused by heat • Electrochromism - color change caused by an electrical current • Solvatochromism - color change caused by solvent polarity • Tribochromism - color change caused by mechanical friction
Photochromism • The reversible transformation of a chemical species between two forms by the absorption of electromagnetic radiation, where the two forms have different absorption spectra. • Electrocyclic ring closing reaction
UV/Vis Studies of Photochromic Transformation • First compound used produced results indicative of degradation
Photostationary State • The equilibrium chemical composition under a specific kind of electromagnetic radiation
Parallel vs. Antiparallel UV light
Monitoring Closing by NMR Open form After 10 min of irradiation
Nitroxyl Release • Tried heating open ring form in xylene/water at 140° C
Future Plans • Optimize retro-Diels Alder reaction and HNO release • Optimize side groups to obtain a higher percent in the closed conformation
References • Fukuto, J.M.; Dutton, A.S.; Houk, K.N. “The chemistry and biology of nitroxyl (HNO): a chemically unique species with novel and important biological activity,” Chembiochem,2005, 6, 612–619. • Lopez, B. E.; Shinyashiki, M.; Han, T. H.; Fukuto, J. M. “Antioxidant actions of nitroxyl (HNO),” Free Radical Biol. Med.2007, 42, 482–91. • Atkinson, R. N.; Storey, B. M.; King, S. B. “Reactions of Acyl Nitroso Compounds with Amines : Production of Nitroxyl (HNO) with the Preparation of Amides” Tetrahedron Lett.1996, 37, 9287–9290. • Irie, M., “Diarylethenes for Memories and Switches,” Chem. Rev.2000, 100, 1685–1716. • Lemieux, V.; Gauthier, S.; Branda, N. R. “Selective and sequential photorelease using molecular switches,” Ang. Chem. Int. Ed.2006, 45, 6820–6824. • Erno, Z.; Asadirad, A. M.; Lemieux, V.; Branda, N. R. “Using light and a molecular switch to “lock” and “unlock” the Diels-Alder reaction,” Org. Biomol. Chem.2012, 10, 2787–2792.
Acknowledgements • Kevin Schultz, Ph.D • Goucher Chemistry Department • Claasen Summer Research Fund • KirkbrideLoya • Jaclyn Kellon • Kat Flanagan • Marie McConville