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Thesis advisor: Jia Niu / Thesis advisor: Abhishek Chatterjee / The functions of natural nucleic acids such as DNA and RNA have transcended from serving as the primary information carrier in cells and have emerged as a new class of functional material with applications encompassing medicine, diagnosis, and research tools. While the vulnerability of natural nucleic acids to nuclease degradation as well as the lack of chemical functionality have imposed a significant constraint on their ever-expanding applications, scientists have put in the effort to develop new classes of synthetic nucleic acids (XNAs) to overcome current limitations. In this dissertation, we will describe the development of a novel XNA oligonucleotide structure, the “click handle-modified FANA” (cmFANA), as the next-generation nucleic acid-based biopolymer that is capable of post-polymerization functionalization and evolution. In this dissertation, we divide our graduate research into three chapters: the development of the essential building block for cmFANA and the synthesis of cmFANA oligonucleotide as Chapter 1; the evolution and application of cmFANA as a sugar-presenting affinity reagent that targets disease-related Carbohydrate-Binding Proteins (CBPs) as Chapter 2; and other collaboration projects as Chapter 3. Together, we described a highly potential XNA structure that goes beyond established impressions of nucleic acids and carries the ability to be a versatile platform technology. / Thesis (PhD) — Boston College, 2023. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第23238号 / 農博第2445号 / 新制||農||1083(附属図書館) / 学位論文||R3||N5328(農学部図書室) / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 渡邊 隆司, 教授 植田 充美, 教授 梅澤 俊明 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

My research involved in two different areas, development of novel glycosylation methodology and scope in oligosaccharide synthesis. A new scaffold for antibiotic development targeting the bacterial cell wall: Total synthesis of Albocycline and its analogs to see the mechanism of action in cell wall biosynthesis. Developed novel gem-dimethyl analogs of Fraser-Reid’s NPGs from 3,3-dimethyl 4-pentenol and 2,2-dimethyl 4-pentenol. These donors are stable toward acidic and basic conditions, which makes them step-efficient when compared to other glycosylating agents. The scope and reactivity of 3,3-dimethyl 4-pentenyl glycosides of glucose, mannose, galactose, and N-acetylglucosamine have been studied extensively for oligosaccharide synthesis. The donors are readily prepared from commercial starting materials and both glycosylation and hydrolysis yields are in the synthetically useful in oligosaccharide synthesis. NSMD methodology introduced a key step in albocycline synthesis, where (‒)-albocycline has great biological activity against “superbug” methicillin-resistant Staphylococcus aureus (MRSA). We hypothesize that albocycline inhibits the first committed step in bacterial cell wall biosynthesis. We have successfully completed two generation syntheses of albocycline. Vinylogous aldol on the left-handed fragment, aldehyde to get selectively up alcohol at the C-8 position using Davis-Ellman sulfinylimine chemistry and then oxidation with Davis oxaziridine to access requisite stereochemistry at C-4 alcohol followed by Horner-Wadsworth-Emmons to access seco-acid. Finally, a Keck macrolactonization reaction provided access to desired (‒)-Albocycline. / Chemistry

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