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Showing 1 to 8 of 8 for “"ring C"”.
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Studies of paclitaxel analogs modified in ring C
… relationship of the C-6 position and the ring C skeleton of paclitaxel, it was goal of this research to synthesize paclitaxel analogs modified in ring C in order to evaluate the effects of these modifications on biological activity and to reveal the chemistry of paclitaxel. The inactivity …
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Approaches towards C-10-hydroxylated analogues of narciclasine
… of aromatic compounds, as precursors to ring C, and of highly oxygenated aromatic molecules to construct ring A. The document also reports a detailed account of the protocols studied for the intramolecular formation of ring B. Experimental data and spectral data are provided for the novel …
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Trace Diagrams, Representations, and Low-Dimensional Topology
… concerns a certain basis for the coordinate ring of the character variety of a surface. Let G be a connected reductive linear algebraic group, and let S be a surface whose fundamental group pi is a free group. Then the coordinate ring C[Hom(pi,G)] of the homomorphisms from pi to G is …
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Stereospecific Syntheses from Podocarpic Acid
… of diterpenoids possessing an aromatic ring-C is discussed and the assignment of configuration of the 6-bromo substituents from n.m.r. and n.0.e. data is examined. A preliminary investigation into the possibility of preparing a 9a-methyl steroidal analogue by addition of a cyclopentatone …
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Pressure dependence of the luminescence and Raman modes in polyfluorene
… the 1342 cm-1 and 1290 cm-1 modes from phenyl rings connecting the monomer units, and the 1600 cm-1 modes from the intra-ring C-C stretch. All Raman modes analyzed shift to higher energies with pressure. Some of the phonon lines exhibit an antiresonance effect at higher pressures that is …
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Computational thermochemistry of hydrocarbons, oxygenates, cyclic alkanes, and furans
… fuel blends. Methoxyfurans show strong furan ring C---H BDEs of 120 kcal mol-' with a decrease to 98 kcal mol^{-1} for the methoxy-methyl C---H bonds. 2-methylfuran hydroperoxide and alcohol species have over 40 kcal mol^{-1} ranges for the O---O BDEs and alcohol O---H BDEs. Oxidation of …
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Synthese des ABCD-Ringsystems und absolute Stereochemie des Pyrrol-Imidazol-Alkaloids Palau'amin aus dem Meeresschwamm Stylotella aurantium
… Aufgrund der viel größeren Spannung des ABCD-Ringsystems ließ sich 210 allerdings unter keinerlei Bedingungen cyclisieren. Ähnlich reagierte das Atkinson-Reagenz 159, wobei allerdings der Eintritt eines externen Nukleophils in die Position C-10a folgte. Interessanterweise konnte ausgehend vom …
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Experimental and theoretical vibrational spectroscopic studies of diketopiperazines
… wavenumber than that of other DKPs where the ring, essentially, adopts a boat conformation. The degradation of D-cycloserine was examined by 1H-NMR spectroscopy. The resulting degradation products, 3,6-bis(aminoxymethyl)-piperazine-2,5-dione (AMDKP) and 3,6-dimethylene-piperazine-2,5-dione …