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Showing 1 to 20 of 35 for “"Cyclobutane"”.
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Synthesis of Novel Cyclobutane Nucleoside Analogues
A synthesis of cyclobutane nucleosides is described. The method involved the triflation of a -hydroxymethyl-cyclobutanone and its subsequent displacement by a 6-chloropurinyl anion to generate N-7 and N-9 regioisomers. The stereoselective reduction of the N-alkylated ketones yielded the …
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Synthesis and Development of Novel Cyclobutane Mechanophores
… synthesis and study of a systematic series of cyclobutane mechanophores, methodology was developed for measuring relative mechanophore reactivity rates and results from these studies were compared to experimentally determined reactivity rates. The straightforward calculations and experimental …
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CRYSTAL ENGINEERING STUDIES ON THE MOLECULAR SALTS AND SILVER(I) COORDINATION COMPOUNDS FOR [2+2] CYCLOADDITION REACTION IN THE SOLID STATE
… a particular isomer of the corresponding cyclobutane compounds. The crucial role of the anions in the selective preorganization before photodimerization and the acid catalysed isomerisation of the cyclobutane derivatives have been explored. It also has been shown how the cooperation of …
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Synthetic Methodology and Application of Enamine [2+2] Cyclisations for Cyclobutane Synthesis. Development of Integrin Antagonists as Anticancer Therapeutics Towards a Total Synthesis of Providencin
Cyclobutanes represent an underutilised structural feature in medicinal chemistry, partially due to difficulties in forming them in an easy and controlled manner. Herein is described their application to a drug discovery project and development of the enamine [2+2] cyclisation; a straightforward …
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Modulation of Cis-syn Cyclobutane Dimer Formation and Deamination at CpG sites by Nucleosome Particles and Its Implications for Deamination Bypass Mechanism for the Origin of C to T Mutations
… sites, which are also sites of preferential cyclobutane pyrimidine dimer: CPD) formation. CPDs containing C or 5-methylcytosine: mC) are not stable and spontaneously deaminate to U or T at pH 7 and 37°C over a period of hours or days. Deamination of Cs or mCs in CPDs is highly mutagenic …
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Photolyase: Its Damaged DNA Substrate and Amino Acid Radical Formation During Photorepair
… bonds between adjacent pyrimidines. Cis-syn cyclobutane pyrimidine dimers (CPD)constitute the most abundant primary lesion in DNA. Photolyase, a light-activated enzyme, catalytically repairs these lesions. Although many steps in the photolyase-mediated repair process have been mapped, details …
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Enantioselective synthesis and reactivity of bicyclobutanes: strained molecular platforms for 4-, 5-, and 6-membered ring synthesis and rhodium(II)-catalyzed reactions of diazoesters with organozinc reagents
… a new method for enantioselective synthesis of cyclobutanes, the total synthesis of cyclobutane-containing natural products, the development of the first examples of transition-metal catalyzed vinylcyclobutane ring expansion reactions, and the rhodium-catalyzed organozincation of diazoesters. …
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Synthesis and Use of a Tetradentate Ligand With C4v Symmetry: 1alpha, 2alpha, 3alpha, 4alpha-Tetrahydroxy- 1beta, 2beta, 3beta, 4beta-Tetramethylcyclobutane
… derivatives designed as possible precursors of a cyclobutane-based tetradentate ligand of C$\sb{\rm 4v}$ symmetry. A new synthetic dehydrogenation reaction to form carbon-carbon double bonds, using the in situ combination of potassium tert -butoxide and tert -butyl hypochlorite, is presented. The …
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Second-site inhibitors of the estrogen and androgen hormone receptors
… coactivator binding inhibitors, a tetra-aryl cyclobutane compound that showed potent estrogen receptor/coactivator disruption was unexpectedly isolated. This compound stemmed from the photocycloaddition of 2,4-dichloro-6-styrylpyrimidine, an intermediate in the synthesis for a number of the …
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Biochemical and Genetic Studies on Origin Recognition and DNA Synthesis From the Mesophilic Archaeon Methanosarcina Acetivorans
… was able to synthesize through abasic DNA and cyclobutane pyrimidine dimers, and these activities were stimulated by the cognate PCNA. Fascinatingly, unlike most translesion DNA polymerases previously described, MacDinB synthesized an unusually long product (∼7.2 kb) in the presence of the …
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Step-Growth Polymerization Towards the Design of Polymers: Assembly and Disassembly of Macromolecules
… of microelectronic devices. In particular cyclobutane diimide functionality within polyimides and poly(siloxane imides) and o-nitro benzyl ester functionality within polyesters acted effectively as chromophores to this end. Thermal solution imidization allowed for the effective synthesis of …
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Mechanistic Studies of Donor-Acceptor Cyclopropanes
… of synthetic organic chemistry. In addition, cyclobutane 1,1-diesters were also investigated as a source of donor-acceptor cyclobutanes. Specifically, their use in cycloaddition reactions has been developed to include the reaction of cyclobutanes with cis-diazenes, providing access to …
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Donor-Acceptor Cyclobutanes and Their Application for Heterocycle Synthesis and Progress Towards Biselide A
The chemistry of cyclobutane-1,1-diester has been investigated with aldehydes and alkyne reaction partners independently of each other. Under Yb(OTf)3 catalysis donor-acceptor cyclobutanes undergo a formal [4+2] cycloaddition with aldehydes to generate tetrahydropyrans exclusively in a cis …
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Jednoduchý elektrochemický DNA biosenzor pro detekci poškození DNA způsobeného UV zářením
… DNA damaging agent. Major DNA lesions, such as cyclobutane pyrimidine dimers (CPDs) and pyrimidine-(6-4)-pyrimidone (6-4PPs) photoproducts, are carcinogenic and mutagenic. UV induced DNA damage was investigated using a simple electrochemical DNA biosensor based on an ultra-trace graphite …
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The photochemistry of 2,4- and 2,6-cyclo-octadienone
… The, exact configuration of the dimer at the cyclobutane ring has not yet been determined. Photolysis in methanol and furan also gave products in which the elements of methanol or furan had been added to the dienone. Low temperature photolysis techniques also showed that this molecule was …
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DNA polymerase interactions and their role In translesion synthesis substitutions.
… is capable of TLS past ultraviolet (UV)-induced cyclobutane pyrimidine dimers (CPDs) as well as cisplatin-induced Pt-GG intrastrand crosslinks. Cisplatin is a well-known cancer treatment used to damage the DNA of cancer cells by generating lesions such as the Pt-GG intrastrand crosslink. By …
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Metal catalyzed generation of reactive benzomethane intermediates for the synthesis of benzopyrans, tetrahydroquinolines and chiral aryl methanes
… stereocenters about the pyran B-ring and a trans-cyclobutane. The core B-ring of the natural product is assembled in a convergent step using a o-hydroxybenzyl alcohol and an olefin. The penultimate benzyl deprotection and diformylation steps completed the synthesis. In collaboration, a cell …
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Application of Femtosecond lasers in confocal and scanning tunnelling microscopy
… (3P). This process leads to the formation of cyclobutane pyrimidine dimmers (CPDs) in the DNA chain. Proliferating Cell Nuclear Antigen (PCNA), involved in the repair of these lesions is tagged with Green Fluorescent Protein (GFP) to visualise the repair process. Damage is detected at peak …
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Total syntheses of (±)-dracephalone A and (±)-dracocequinones A and B, progress towards a total synthesis of cassiabudanols A and B, and synthetic studies towards total synthesis of N-oxy-diketopiperazine containing natural products.
… of (R)-14-hydroxycarvone. Screening of cyclobutane fragmentation revealed SnCl4 as the most reliable Lewis acid in various scales. Subsequent manipulation of (R)-14-hydroxycarvone set the stage for Favorskii rearrangement albeit mixture of diastereomers. Further functional group …
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