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 20 of 136 for “"deprotection"”.
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Control of regioselectivity:oxidation and deprotection
… over a palladium catalyst. Oxidative deprotection methods are also available, particularly when the MPM (4-methoxybenzyl) group is used in place of Bn. The NAP (2-naphthylmethyl) protective group has recently been introduced and has been shown to be removed by hydrogenolysis more …
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Synthesis and Application of Boronic Acid Derivatives
… During the synthesis of this compound, published deprotection methods were not suitable to deprotect the pinacol group. A two-step protocol for pinacolyl boronic ester deprotection via a diethanolamine protected intermediate was successfully developed with the advantages of mild reaction …
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Total Synthesis and Stereochemical Revision of Pestalospirane B
… natural product. Initial attempts at late stage deprotection of isopropyl dimer 314 were unsucessful, thus a revision in protecting group strategy was enforced where access to the natural product was envisioned to allow deprotection prior to dimerisation of acetal 342. Attention, therefore …
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Synthesis and Antifungal Evaluation of Barbiturate Saponins And Progress Towards Cysteinyl Metal Peptides
… the barbiturate without requiring protection and deprotection of saccharides. Efficient methods were developed for synthesis of 3<em>β</em> derivatized steroid derivatives containing ether, carbonate, ester and carbamate linker. Synthesized mono and disaccharide barbiturates were incorporated into …
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Preparation of arylphosphinic acid derivatives as building blocks for binding sites
… derived from methyl phosphinate. Deprotection of the bisphenylalanylphosphinate and mixing it with a metal ion lead to self-assembled cyclic metal complex of bisphenylalanyl phosphinic acid. Selective deprotection and peptide coupling of bisphenylalanylphosphinate generate a …
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Synthesis of Delta(3)-Imidazolines as Latent Forms of Peptidyl Trifluoromethyl Ketones
… ketones during typical peptide Fmoc deprotection and elongation reactions. In the final step, the imidazoline was hydrolyzed with dilute acid, which afforded the trifluoromethyl ketone in good yield. This process was carried out without the use of oxidants and was shown not to affect …
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Telomere-Driven Tetraploidy and its Relevance to Cancer
… in early tumorigene sis. Prolonged telomere deprotection caused by inactivation of the telomeric proteins POT1a and POT1b leads to tetraploidy in p53/Rb de cient mouse cells. Irreversible telomere deprotection and other forms of persistent DNA damage induce a prolonged G2 phase followed by …
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Part I: The Study Of 2-Aryl-1,3-Dithiane Derivatives As Pronucleophiles In Palladium-Catalyzed Allylic Alkylation And Propellylation Part Ii: Ligand-Free Palladium-Catalyzed Allylic Amintion Of Hydrazone Derivatives Part Iii: Synthesis Of Criegee Intermediate Precursors
… products in good to excellent yields. Deprotection of these products leads to valuable aryl alkyl ketones. The palladium-catalyzed allylic alkylation of 2-aryl-1,3-dithianes is examined in chapter 1. A direct synthesis of unsaturated ketones via a one-pot allylation-oxidation …
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The use of immobilised crown ethers as in-situ protecting groups for organic synthesis within flow reactors
… pathway (by at least two steps – protection and deprotection), generally leading to an increase in cost and a decrease in yield. The protecting group is often selected based upon the deprotection conditions, leading to the requirement for orthogonal protecting groups. Crown ethers are commonly …
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A small molecule synthesizer
… and are universally susceptible to general mild deprotection conditions. Additionally, MIDA boronates can be prepared by a variety of synthetic methods on multi-gram scale and they demonstrate significantly improved reaction yields with slow-addition cross-coupling (SACC). It was understood that …
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Living Polymerization for the Introduction of Tailored Hydrogen Bonding
… initiated polyisoprenes proved that facile deprotection was not possible and residual catalyst was not removable from the polymer. However, polymers initiated with 3-(t-butyldimethylsilyloxy)-1-propyllithium were quantitatively hydrogenated and deprotected under relatively mild conditions to …
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Solid Phase Synthesis of M-Phenylene Ethynylene Oligomer Heterosequences
… days, efforts were taken to limit the need for deprotection steps and ensure cross-coupling conditions were complete within two hours. This led to the ability to produce mPE heterosequence hexamers with aryl bromide and terminal acetylene endgroups in good yields (typically 55-75%), in twelve …
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Synthesis and structure-activity relationships of ring D alkyl 19-norsteroids
… of which furnished the 16β-alcohol. Routine deprotection of the epimeric pair of methylene 16-alcohols gave the derived estriol analogues, which were subjected to biological evaluation. Treatment of the 14α,15α methylene16-ketone with lithium in liquid ammonia gave …
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Part I: Rapid Synthesis of Dendrimers by an Orthogonal Coupling Strategy. Part II: Design, Synthesis, and Characterization of Hydrogen-Bond Mediated Self-Assembling Dendrimers
… synthetic steps needed by obviating protection-deprotection and activation chemistry.
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Synthesis of P-Stereogenic Bisphosphine Ligands: Application as Hemi-labile Ligands in the Asymmetric Pauson-Khand Reaction
… enantiomeric ratio up to 99:1 er. After borane deprotection of the bisphosphines using DABCO, hemi-labile ligands A and B were obtained. These hemi-labile ligands contain a phosphorus lone pair as a strong coordinating group and a sulfur lone pair on the P=S group as a weak coordinating group. …
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Synthesis of triplex-forming oligonucleotide conjugates of the anticancer drug temodal
… were evaluated. A novel cleavage and deprotection procedure was developed which allowed for the solid phase synthesis of the base-sensitive TFO-drug conjugates using a recently developed silyl-linked controlled pore glass (SLCPG) support. Covalent attachment of either temozolomide or …
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Synthesis and structure-activity studies of skeletally modified estradiol analogues
… 17β-diol, by a hydrogenation, desulfonylation, deprotection reaction sequence. The unexpectedly complex result for the cycloaddition reaction was interpreted with the assistance of other cycloaddition reactions of the Δ¹⁴,¹⁶-dienyl acetate. 17,17-Ethylenedioxy-3-methoxy-9β-estra-l …
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Synthesis of aza-tryptophan derivatives.
… intended product. Subsequent deoxygenation and deprotection of the indole, ring, and the amino and acid functional groups yielded racemic 7-azatryptophan A variety of attempts to synthesize the enantiomerically pure form of 7-azatryptophan were considered. Of those Evans' asymmetric glycine …
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Chemical synthesis of glycosylated oligoribonucleotides for siRNA development
… were synthesized from perbenzylated ribolactone. Deprotection of benzyl-protected ribofuranosyl phenanthrene and pyrene by boron tribromide gave ribofuranosyl phenanthrene and ribopyranosyl pyrene, respectively. UV/vis and fluorescent properties of the ribosides were characterized.
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Synthetic studies on Canangone and beta-Chamigrene
… hydrolysis provided the spirolactone. Subsequent deprotection, Luche reduction and oxidation gave (R*,R*) Canangone and (5R*,6S*)-epi-Canangone. Following the same strategy, optically active (+)-Canangone and (-)-Canangone, and their epimers were synthesized. As a second target, the synthesis of …
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