Global ETD Search
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 17 of 17 for “"epoxide opening"”.
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Endo-selective epoxide-opening cascades in water
… is their biogenesis. Cascades of endo-selective epoxide opening inspired by the biosynthetic proposal and promoted by simple neutral water can provide efficient access to these compounds. Chapter II. Water-Promoted Epoxide Opening Accommodates Methyl Substitution. ... Methyl (Me) substitution …
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Directing group-free endo-selective epoxide-opening cascades
… ladder polyethers features a dramatic series of epoxide opening reactions, elegantly accounts for the structural and stereochemical features of all related natural products, and, in principle, could significantly simplify the synthesis of these extraordinarily complex molecules. In practice, …
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Rhodium-catalyzed epoxide-opening cascades toward brevisin and hemibrevetoxin B
CHAPTER I. Rhodium-Catalyzed Epoxide-Opening Cascades: Formal Synthesis of (-)-Brevisin [chemical formula inserted] [Rh(CO)₂Cl]₂ was found to be an effective catalyst for endo-selective cyclizations and cascades of epoxy-(E)-enoate alcohols, thus enabling the synthesis of oxepanes and …
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Studies on the total synthesis of gambierol via endo-selective epoxide-opening cascades
… using water-promoted endo-selective epoxide-opening cascades to construct the poly-THP motifs. The concentration and temperature effects in the waterpromoted cascades were examined, and an operationally simple protocol was developed for the synthesis of polycyclic cascade products on …
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Nickel-catalyzed coupling reactions and synthetic studies toward ent-dioxepandehydrothyrsiferol via an epoxide-opening cascade
… studies of ent-dioxepandehydrothyrsiferol via an Epoxide-Opening Cascade Dioxepandehydrothyrsiferol is a marine polycyclic ether natural product isolated from the red algae Laurencia viridis.
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Bromonium-Initiated Epoxide-Opening Cascades : total Synthesis of ent-Dioxepandehydrothyrsiferol and Synthetic Studies toward (+)-Scholarisine A
CHAPTER I. Bromonium-Initiated Epoxide-Opening Cascades: Total Synthesis of ent-Dioxepandehydrothyrsiferol Our foray into the total synthesis of ent-dioxepandehydrothyrsiferol has led to the discovery and development of the bromonium-initiated epoxide-opening cascade. This transformation constructs …
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Studies on the total synthesis of gymnocin B
… linear sequence, using three different types of epoxide-opening cascades and one fragment coupling. Synthesis of the KLMNO fragment has been completed in 27 steps longest linear sequence, using one epoxide-opening cascade and one fragment coupling. The completion plan of gymnocin B is also …
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Synthesis of Biologically Relevant Sphingolipid Analogues
… both in a sugar approach as in regioselective epoxide opening. Since these experiments failed to provide a reliable means for introduction of branching, we opted to introduce an extra methylene spacer by use of 1,3-dithiane. Hence, the desired N-homo(dihydro)ceramides have been synthesized in …
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Enantioselective synthesis of pretomanid & investigations of Raman spectroscopy for through-tube monitoring of reactions
… synthesis of pretomanid through a selective epoxide-opening cyclization and late-stage nitration. This route offers a new strategy to access the core of pretomanid and avoids the necessity of the explosive starting material. Chapter 2: Investigations of Raman Spectroscopy for Through-Tube …
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Novel methods and syntheses toward HIV/AIDS and tuberculosis pharmaceuticals
… tuberculosis. The synthesis of the final epoxide intermediate of our route has been achieved on multi-gram scale, and the subject of future investigation will focus on the final epoxide opening reaction. Our proposed route uses readily available, inexpensive starting materials, and would …
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Transformations of carotenoids in the oceanic water column
… alcohols (2-94%), dehydrates (0-6%), and opened epoxides (0-19%). Preliminary results suggest that carotenoid esters are hydrolyzed to free alcohols at a rate determined by the turnover of primary productivity. The dehydrated and epoxide opened intermediates of fucoxanthin represent products of …
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Synthesis and determination of the absolute configuration of Armatol A through a polyepoxide cyclization cascade : revision of the proposed structures of Armatols A-F
… fragment coupling were generated via a triepoxide cascade. Elimination of the secondary alcohol in the oxepane ring proved challenging; however, employing the Shapiro reaction successfully provided the desired oxepene. Ketone and aldehyde tricycles were synthesized in 11 and 7 steps, …
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Synthetic studies toward 6-deoxy-ß-D-ido-heptopyranosides related to capsular polysaccharides of Campylobacter jejuni
… which underwent a trans-diaxial epoxide opening to afford the desired β-D-idopyranoside as the only product. The regioselectivity was attributed to the coordination of a counter-cation to one of the sulfonate oxygens with the help of a neighboring cis-oxygen. The role of the …
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Total Synthesis of the 2-Nitropyrrole Natural Product Heronapyrrole C
… key alkene intermediate 255 was converted into epoxide 274 by Shi epoxidation. The construction of the bis-THF scaffold was achieved by successive double TES deprotection and epoxide opening cyclisation. N-Protection of the 2-nitropyrrole motif was key to the successful synthesis of …
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Triazole-linked reduced amide isosteres: An approach for the fragment-based drug discovery of anti-Alzheimer's BACE1 inhibitors and NH-assisted Fürst-Plattner opening of cyclohexene oxides
… can serve as substrate directing moieties in the opening of cyclohexene oxides. We observed that by judicious choice of conditions we could control the regiochemical outcome of the reaction. These studies demonstrate that an intramolecular anilino-NH hydrogen bond donor can direct Fürst-Plattner …
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The Design, Synthesis, and Evaluation of Zwitterionic and Cationic Lipids for In Vivo RNA Delivery and Non-Viral CRISPR/Cas Gene Editing
… tails introduced via conjugate addition or epoxide opening, and a zwitterionic sulfobetaine head group. ZALs were designed with a combination of cationic and zwitterionic lipid properties, to help stabilize and effectively deliver long RNA molecules. A lead compound, ZA3-Ep10, was effective …
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Synthetic strategies for potential trypanocides
Human African trypanosomiasis (sleeping sickness) is a devastating disease which is endemic in parts of sub-Saharan Africa. It is caused by the protozoan parasite T. brucei, which are transmitted by the bite of infected tsetse flies. Although the disease is fatal if left untreated, there is a lack …