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Development Of An Isotopic Approach For Detailing Heparin Sequences, Qing Guo

Doctoral Dissertations

Heparin/heparin sulfates are carbohydrate polyionic polymers that participate in a host of critically important biological processes such as blood anticoagulation, pathogen infection, cell differentiation, growth, migration and inflammation, to mention a few. A century has passed since heparin’s initial discovery with a fair understanding of its overall composition. Unfortunately, there has been no structural work at the detailed chemical level that might support a synthetic effort. In this study, I utilize a chemical derivatization strategy (dual permethylation) that imparts isotopic structural specificity, which can be followed by step-wise disassembly in an ion trap mass spectrometer, (MSn). A set of analytical …

Formal Synthesis Of Cj-12,954 And Cj-13,014 Using Zinc-Mediated Tandem Chain Extension-Aldol Reaction And Synthesis And Investigation Of Diastereoselectivity Of Hydroxy-Cyclopropyl Peptide Isosteres, Yashoda Naga Deepthi Bhogadhi

Doctoral Dissertations

A formal synthesis of the natural products CJ-12,954 and CJ-13,014 was successfully accomplished using the zinc-mediated tandem chain extension-aldol reaction methodology. This chemistry was performed on a chiral β-keto imide synthesized using a DCC coupling reaction. The diastereoselectivity of the aldol reaction was controlled by an Evans chiral auxiliary. Comparison between the reported and experimental spectral data for the spiroketals confirmed the structural assignment.

The diastereoselectivity of the homologation-cyclization-rearrangement-lactonization reaction of β-keto imide derived from phenyl carbamate-protected proline was studied. Tetra-n-butylammonium fluoride-mediated rearrangement of trimethylsilyl cyclopropanol demonstrated the role of chiral auxiliary and the amino acid stereocenter in controlling the …

Single Chain Technology: Toward The Controlled Synthesis Of Polymer Nanostructures, Christopher Kenneth Lyon

Doctoral Dissertations

A technique for fabricating advanced polymer nanostructures enjoying recent popularity is the collapse or folding of single polymer chains in highly dilute solution mediated by intramolecular cross-linking. We term the resultant structures single-chain nanoparticles (SCNP). This technique has proven particularly valuable in the synthesis of nanomaterials on the order of 5 – 20 nm. Many different types of covalent and non-covalent chemistries have been used to this end.

This dissertation investigates the use of so-called single-chain technology to synthesize nanoparticles using modular techniques that allow for easy incorporation of functionality or special structural or characteristic features. Specifically, the synthesis of …

Syntheses And Characterization Of Linearly Extended Tropylium Salts As N-Type Organic Semiconductors, Jinyu Yang

Master's Theses and Capstones

Organic semiconductors have been of interest to scientists since the 1970s. However, while much attention was focused on p-type organic semiconductors, n-type organic semiconductors were seldom reported. In this thesis, a series of linearly extended tropylium salts (LETS) were synthesized as n-type organic semiconductors and characterized by 1H NMR, 13C NMR spectroscopy, MALDI-TOF-Mass spectrometry and UV-Vis spectroscopy. The proposed synthetic strategy has proven highly suitable to synthesize LETS compounds. UV-Vis spectra of LETS in solution have been studied as well as their stability. Linear extension of the backbones has been found to be an effective way to improve the optical …