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Showing 1 to 18 of 18 for “"Trityl"”.
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Some attempts to prepare triphenylcarbinyl p-toluenesulfonate, trityl tosylate
Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Chemistry, 1950.
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Part I: Development of New Methods for Application in Multicatalytic Reactions Part II: Investigation of Stable Carbenium Catalysts as Hydride Transfer Agents
… transfer reactions. Both cyclopropenium and trityl catalysts are investigated in a reductive etherification method. A study of trityl catalyst structure and initial investigations into the development of chiral trityl catalysts are presented.
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The synthesis, reactivity and application of functionalized alkyl transition metal complexes
… alcohol and 3,5- dihydroxybenzyl alcohol), trityl salt, PPh3, and CO/AgBF4 has also been studied. The new complexes that we obtained are namely: [CpFe(CO)(L){C=O(CH2) 0Br}] ( L = CO and PPh3 ) from the reactions with CO/AgBF4 and PPh3 respectively, . [CpFe(C0)2{CH2=CH{CH2) 4Br]PF6 from the …
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Rapid-Scan EPR and Imaging
… a non-invasive way. Properties of nitroxide and trityl radical imaging reagents have been studied. Developments in rapid scan imaging techniques are reported that improve efficiency of experiments and user-friendliness of software.</p> <p>Relaxation and signal-to-noise ratio (S/N) in pulse …
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Stabile Vinylkationen
… Hydridtransferreaktion aus Alkinylsilanen durch Trityl TPFPB bei Raumtemperatur. Es wird erstmalig die experimentelle Molekülstruktur eines α-cyclopropylsubstituierten Vinylkations vorgestellt. Die Struktur des α-cyclopropylsubstituierten Vinylkations offenbart die strukturellen Konsequenzen der …
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Thermodynamically Driven (Reversible) End-Capping of Pseudorotaxanes to Produce Rotaxanes
… The new guest species were endcapped in situ as trityl ethers to form new thermodynamically stable rotaxanes. Further work to pursue would include synthesis of rotaxanes using functionalized crown ethers for polymerization to make polyrotaxanes and synthesis of self-assembled polymers using this …
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A new cyclohexyl-based chiral auxiliary: application in the total synthesis of (+)-linalool oxide
… best result was obtained by using (±)-trans-2-trityl-1- cyclohexanol ((±)-2.10 (±)-TTC)), resulting in high diastereoselectivity (dr = 97:3) in the resulting THF diols 2.51a/b. The other auxiliaries synthesised gave only moderate to no diastereoinduction. Different methods were used to resolve …
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High field dynamic nuclear polarization methods: Microwave sources and mechanisms
… studies of two unexplored DNP mechanisms in trityl: the three-spin solid effect and resonant mixing. With solid-state microwave sources and Overhauser radicals, DNP is now more accessible as we can achieve reasonable enhancement without the need for a gyrotron. Moreover, as amplifier and …
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Polarizing agents for high-frequency Dynamic Nuclear Polarization : development and applications
… Alternatively, radical mixtures of TEMPO and Trityl, methyl tris(8-carboxy-2,2,6,6-tetramethyl-benzo[ 1 ,2-d:4,5-d']bis( 1 ,3)dithiol-4-yl, improve the probability of the correct EPR frequency separation compared to TEMPO by itself.
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Towards interlocked structures based on H-bonded barbiturate complexes
… groups (anthracenes, olefins) or stoppers (trityl) were also synthesised. The fluorescence properties of anthracene-tagged barbiturates and their kinetics of intramolecular anthracene photodimerisation and thermal return were studied, demonstrating remarkable differences depending on the …
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Stereoselective synthesis of all-C quaternary stereocentres using non-enolisable 1,3-dialdehydes
… pendant benzyloxy group in contrast to a pendant trityl or TBDPS ether group. The diastereoselection of additions to dialdehydes has been rationalised by considering the reactive conformations involved to form the observed diastereoisomer products of these addition reactions. A double addition …
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Towards the Synthesis of Novel Linseed Oil Based Anhydride Compounds
… were all produced as was the pure monoprotected trityl PEGs. The third and final chapter contains the experimental data for the compounds produced in the previous chapter.
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Dinitroxides in Rapid Scan Electron Paramagnetic Resonance Imaging
… organic free-radicals such as triarylmethyl (Trityl) radicals or nitroxides. Attention is given here to an example of a nitroxide that has been structured to provide longer intercellular retention time. In addition to the use of nitroxides as probes, they can also be utilized as nuclear …
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Synthese von Dioxabicyclooctenen und Thymidinderivaten sowie deren Markierung mit PET-geeigneten Nukliden
… Synthese der Precursor 3-N-Boc-1-(3-O-nosyl-5-O-trityl-ß-D-lyxofuranosyl)thymin erhalten, in einem selbst entwickelten Synthesemodul mit [18F]Fluorid umgesetzt und anschließend hydrolysiert. Die Aufarbeitung der Reaktionslösung erfolgte mittels HPLC und lieferte [18F]FLT in guten Ausbeuten, …
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Computational Studies of Protonated Cyclic Ethers and Benzylic Organolithium Compounds
… of THF-solvated fluorenyl, diphenylmethyl, and trityl lithium was studied computationally. Minimum-energy equilibrium geometries of explicit mono, bis and tris-solvated contact ion pairs (CIPs) and tetrakis-sovlated solvent separated ion pair (SSIPs) were modeled at B3LYP/6-31G*. Associative …
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Borenium Cations as Catalysts for the Reduction of Organic Molecules and Mechanistic Investigations into their Mode of Operation
… hydride. Another borenium ion, synthesized from trityl tetrakis-pentafluorophenyl borate, DABCO, and HBpin did not contain a nucleophilic borohydride counterion and it was isolated in the solid state. This salt was also found to reduce the same substrates with similar yields and reaction times. …
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An Automated Syringe Pump System For Improving The Reproducibility of Dynamic Hyperpolarized Mri Phantoms
… in unpaired electrons, in this case from a Trityl radical, can convey their polarization to a nearby <sup>13</sup>C nucleus through microwave irradiation. Pyruvate, which plays a central role in metabolism, is involved in aerobic glycolysis, a primary energy pathway for cancer cells. In this …
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Development of Low Frequency Electron Paramagnetic Resonance Methods and Instrumentation for Biological Applications
… scan images were collected of nitroxide and trityl radicals <em>in vitro</em> up to 4 dimensions.</p> <p>New methods were tested that use rapid scan, frequency steps, and field jumps to measure electron spin lattice relaxation (T<sub>1</sub>) at 1 GHz. Overall good agreement of the relaxation …