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1.
2.
Jocelyne Hellou Raymond J. Andersen Shahin Rafii Edward Arnold Jon Clardy 《Tetrahedron letters》1981,22(42):4173-4176
The structure of luteone (), a twenty three carbon terpenoid, has been solved by performing a single crystal x-ray analysis on a 3,4-dinitrophenylhydrazone derivative. 相似文献
3.
Benoít Rigo Etienne Tullier Didier Barbry Daniel Couturier Vincent Warin Jocelyne Lamiot Franois Baert 《Journal of heterocyclic chemistry》1990,27(5):1383-1386
3,5-Dihydrobenz[f]indolizin-3-one was prepared by a novel dehydration reaction involving the heating of 1,2,3,5,10,10a-hexahydro[f]indolizine-3,10-dione with polyphosphoric acid. The structure of this new compound was established by X-ray crystallography, by nmr spectroscopy and by reduction to the known products 1,2,3,5-tetrahydrobenz[f]indolizin-3-one and 1,2,3,5,10,10a-hexahydrobenz[f]indolizin-3-one. 相似文献
4.
Fernandes SA Nachtigall FF Lazzarotto M Fujiwara FY Marsaioli AJ 《Magnetic resonance in chemistry : MRC》2005,43(5):398-404
'Non-covalent synthesis' of novel chiral hosts (calix[6]arene-chiral amine complexes) and its application to enantiomeric discrimination was investigated by (1)H NMR spectroscopy. The topology of a ternary complex was proposed for the calix[6]arene-amine-sulfoxide to rationalize the chiral recognition. 相似文献
5.
C. J. Joachain A. Makhoute A. Maquet R. Taieb 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1992,23(4):397-401
The influence of a strong laser field on the dynamics of fast (e, 2e) collisions in helium is analyzed in the asymmetric, coplanar geometry. The interaction of the laser field with the incident, scattered and ejected electrons is treated in a non-perturbative way, while the remaining interactions are treated by using first order perturbation theory. Detailed calculations are performed for an incident electron energyE k i=600 eV, an ejected electron energyE k B=5 eV and a scattering angle θ A =4°. The influence of the laser parameters (photon energy, intensity and direction of polarization) on the angular distribution of the ejected electron is analyzed. We find that in general the triple differential cross sections are strongly dependent on the dressing of the projectile and the target by the laser field. 相似文献
6.
Riek R Fiaux J Bertelsen EB Horwich AL Wuthrich K 《Journal of the American Chemical Society》2002,124(41):12144-12153
Transverse relaxation-optimized spectroscopy (TROSY) or generation of heteronuclear multiple quantum coherences during the frequency labeling period and TROSY during the acquisition period have been combined either with cross-correlated relaxation-induced polarization transfer (CRIPT) or cross-correlated relaxation-enhanced polarization transfer (CRINEPT) to obtain two-dimensional (2D) solution NMR correlation spectra of (15)N,(2)H-labeled homo-oligomeric macromolecules with molecular weights from 110 to 800 kDa. With the experimental conditions used, the line widths of the TROSY-components of the (1)H- and (15)N-signals were of the order of 60 Hz at 400 kDa, whereas, for structures of size 800 kDa, the line widths were about 75 Hz for (15)N and 110 Hz for (1)H. This paper describes the experimental schemes used and details of their setup for individual measurements. The performance of NMR experiments with large structures depends critically on the choice of the polarization transfer times, the relaxation delays between subsequent recordings, and the water-handling routines. Optimal transfer times for 2D [(15)N,(1)H]-CRIPT-TROSY experiments in H(2)O solutions were found to be 6 ms for a molecular weight of approximately 200 kDa, 2.8 ms for 400 kDa, and 1.4 ms for 800 kDa. These data validate theoretical predictions of inverse proportionality between optimal transfer time and size of the structure. The proton longitudinal relaxation times in H(2)O solution were found to be of the order of 0.8 s for structure sizes around 200 kDa, 0.4 s at 400 kDa, and 0.3 s at 800 kDa, which enabled the use of recycle times below 1 s. Since improper water handling results in severe signal loss, the water resonance was kept along the z-axis during the entire duration of the experiments by adjusting each water flip-back pulse individually. 相似文献
7.
The natural furocoumarin dehydroxyglaupalol and two analogs were prepared by reaction of the appropriate 4-hydroxy-coumarin with 3-chloro-3-methylbutyne in basic medium, followed by catalytic hydrogenation of the exo double bond. 相似文献
8.
Florent Jasinski Emeline Lobry Abraham Chemtob Céline Croutxe-Barghorn Loïc Vidal Ludovic Josien Jocelyne Brendlé Adrien Criqui 《Colloid and polymer science》2014,292(12):3095-3102
When finally processed to provide the function for which the latex was selected―binding, protecting, finishing―components such as surfactant, costabilizer or initiator become generally useless, not to say detrimental. In this study, we show that miniemulsion photopolymerization provides a suitable method to create latex without the apparent addition of these three compounds. Indeed, UV-driven monomer self-initiation can create initiating radicals without the aid of initiator, the fast in situ photogenerated polymer can hinder Ostwald ripening with the assistance of external costabilizer, and finally, UV-transparent clay can replace conventional surfactant to ensure colloidal stabilization. Each strategy has been developed individually before being combined together to end up with a unique miniemulsion procedure free of initiator, costabilizer and surfactant. Such approach paves the way to a simplified and environmentally improved pathway towards aqueous polymer dispersions. 相似文献
9.
Lejeune C Coelho C Bonhomme-Coury L Azaïs T Maquet J Bonhomme C 《Solid state nuclear magnetic resonance》2005,27(4):242-246
We show that it is possible to efficiently transfer magnetization from 31P to 29Si, using variable amplitude CP MAS experiment. This experiment is demonstrated by using Si5O(PO4)6, the synthesis protocol of which is described. From the obtained results, we show that the experiment allows the spectral edition of 29Si spectra from 31P→29Si CP, enabling the studies of derivatives involving Si–O–P linkages, such as phosphosilicate glasses, microporous silicoaluminophosphates (SAPO) and bioactive phosphosilicates. 相似文献
10.
Chrostowska A Miqueu K Pfister-Guillouzo G Briard E Levillain J Ripoll JL 《Journal of Molecular Spectroscopy》2001,205(2):323-330
The flash vacuum thermolysis of cycloalkenyl allyl sulfides, potential precursors of unsubstituted cycloalkenethiones, has been investigated by photoelectron spectroscopy. This technique allowed us to characterize in the gas phase very reactive species of this series, the conjugated and nonconjugated cyclopentene and cyclohexenethiones, and to compare the reactivity of these compounds. The assignment of the PE spectra is supported by electronic structure calculations, particularly by the HF method at the MP2 level and the density functional theory (DFT) using the B3LYP and BP86 functionals with the 6-311G(d, p) basis set. Copyright 2001 Academic Press. 相似文献