Description
Part 1 Synthesis and Fluorescent Properties of New tC Derivatives The relationship between chemical structure and photophysical properties of fluorophores is an area in need of more development so that more tailored and customized fluorophores can be created and used in desired applications. In my research, I built on past research dealing with tricyclic cytidines, a fluorescent nucleoside analogue, to further explore how different electron withdrawing groups (EWGs) and electron donating groups (EDGs) can affect the fluorescence of a known, well characterized scaffold. Previous work in our group explored the synthesis of a subset of derivatives of this tC compound. My research advanced this by synthesizing the necessary phosphoramidite precursors needed to incorporate the compounds into synthetic DNA to explore the resulting photophysical properties. We originally suspected that stronger EWG’s on the tC scaffold results in a higher overall quantum yield and vice versa. After determining the quantum yields of (8-CN)tCo and (8-DEA)tC, the quantum yields of these new derivatives the results showed that when modifying the nature of the EDG or the EWG, the fluorescent properties can change significantly and our initial hypothesis of fluorescence increasing with a stronger EWG held true in general. When characterizing the (8-DEA)tC, unique and unexpected fluorescent properties were observed. Although the free nucleoside had unimpressive fluorescent properties and a very low quantum yield, once inside duplex DNA the observed quantum increased up to 20-fold. Part 2 ProDrug Chemistry The goal of this research was to develop a new method for esterification of phosphonic and phosphoric acids via diazoalkane chemistry. Phosphoric and phosphonic acids are prevalent moieties seen in inhibitors for phosphatase enzymes and DNA/RNA polymerases, but cannot be delivered as drugs because their negative charges prevent entry into cells. Prodrug chemistry temporarily masks those charges allowing entry into the cell. In this research, we adapt chemistry recently developed to esterify carboxylic acids in a selective, mild manner and apply it to phosphoric and phosphonic acids. By exploring modifications to the reactions, reagents and conditions, we hope to better understand the reaction mechanism so that it can be optimized to the highest yields possible.
