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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 10 of 10 for “"Oxocarbenium"”.
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Syntheses of C-glycoside natural products via oxocarbenium cationic intermediates
… synthesis of C-glycoside natural products via oxocarbenium cationic intermediates with a brief introduction given in the first chapter. The second chapter examines our approach to the first total synthesis and absolute configuration of the antibiotic (+)-bruguierol C. The key step is the …
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Oxocarbenium Ion and Alkene Metathesis Strategies for the Synthesis of Complex Cyclohexanes
… synthesis of highly oxygenated cyclohexanes: (1) Oxocarbenium Ion Cyclization (OCC) and (2) Ring Closing Metathasis (RCM).</p> <p>Chapter one gives a review of the literature on the synthesis for highly oxygenated cyclohexanes.</p> <p>Previous results from this laboratory have shown that OCCs on …
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Development of transition state analogues targeting chitinases and oligosaccharyl transferase
… to share similar transition states involving an oxocarbenium ion. To understand the mechanism of OT and discover potent and selective inhibitors against different chitinases, our intent was to utilize the common transition state analogue for both enzymes and systematically introduce additional …
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Development and Investigation of a Dehydrative Glycosylation With Activated Diphenyl Sulfonium Reagents
… the reactive intermediate is likely a glycosyl oxocarbenium.
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I. Microwave-Influenced Diversity-Oriented Synthesis Of Biologically Relevant Small & Natural-Product-Like Molecules Via Multicomponent Coupling Reactions Ii. Synthetic Studies Toward The Total Synthesis Of The Repeating Tetrasaccharide Unit Of Zwitterionic Polysaccharide Ps A1
… to study entirely neutral glycosylation via oxocarbenium ion.</p> <p>We also investigated the total synthesis of the repeating tetrasaccharide unit of zwitterionic polysaccharide PS A1 using different strategies. PS A1 is known to modulate T-cell response via MHC-II pathway and shown to …
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Synthesis And Á-Stereoselective Sialylation Of Kdn And Late Stage Modification Of Neuraminic Acid Sialosides
… mean plane of the pyranose ring destabilizes any oxocarbenium ion thus necessitating a higher cone voltage to initiate mass spectral fragmentation. By analogy the cyclic protecting group retards oxocarbenium ion formation in the course of glycosylation reactions and so promotes associative …
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Development and applications of acid degradable polymeric materials
… trap for chain shattering. Thus, transient oxocarbenium ion formation with an organic acid induces intramolecular cyclization to depolymerize a polyurethane (PU) backbone at room temperature in anhydrous or low moisture environments. With minimal chemical modification, the resulting …
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Structural and functional analysis of glycosyltransferase mechanisms
… to initiate and stabilize a dissociative oxocarbenium ion do not abolish enzyme activity. The catalytically inactive substrate analogs depict the acceptor nucleophile to lay very close to the anomeric carbon (2.5 Å), which is considerably closer than the closest observed enzymatic dipoles …
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N9 Alkylation and Glycosylation of Purines; A Practical Synthesis of 2-Chloro-2'-deoxyadenosine
… group with consequent stabilization of the oxocarbenium cation, and lowering the activation energy by introduction of trichloroacetimidate at the anomeric carbon.</p> <p>(b) 6-Heteroaryl functions [6-(1,2,4-triazol-4-yl) and 6-(imidazol-1-yl)] were introduced into purine derivatives for …
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Mechanistic insights into the PARP10-mediated ADP-ribosylation reaction and analysis of PARP10's subcellular localization
… placed in a favorable position to stabilize the oxocarbenium transition state of the reaction. This function is normally executed by the catalytic glutamate in ADP-ribosyltransferases and bona fide PARP enzymes. Consequently, a novel catalytic mechanism for PARP10 is proposed, in which the acidic …