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21.
Stéphanie Gracia Cédric Marion Jullien Rey Florence Popowycz Stéphane Pellet-Rostaing Marc Lemaire 《Tetrahedron letters》2012,53(25):3165-3168
Horner-Wadsworth Emmons olefination followed by asymmetric hydrogenation allowed the first synthetic access to the chiral thiotryptophan with good enantiomeric excess. Oxazolidinone formation followed by a Pictet–Spengler condensation provided the benzothiophenic analog of Azatoxin. 相似文献
22.
Mihaela RomanBruno Andrioletti Marc Lemaire Jean-Marie BernardJohannes Schwartz Philippe Barbeau 《Tetrahedron》2011,67(7):1506-1510
Using HMDS as catalyst for the trimerization of isocyanates presents many advantages as the expected isocyanurate is not contaminated by the catalyst or other side-products resulting from its degradation. In addition, HMDS presents a low toxicity, and is compatible with industrial applications. This article describes the hexamethyldisilazane (HMDS)-catalyzed trimerization of octylisocyanate. Experimental investigations and mechanistic considerations indicate that the true catalyst of the trimerization is trimethylsilyloctylamine, which results from the preliminary condensation of HMDS with octylisocyanate. 相似文献
23.
F. Chitry S. Pellet-Rostaing A. Guy J. Foos M. Lemaire 《Journal of Radioanalytical and Nuclear Chemistry》2002,251(1):155-157
The separation of Am(III) from a mixture of lanthanides(III) was performed in aqueous medium by nanofiltration combined with a complexation step using a DTPA derivative as selective complexing agent. 相似文献
24.
Barclay TM Hicks RG Lemaire MT Thompson LK Xu Z 《Chemical communications (Cambridge, England)》2002,(16):1688-1689
The synthesis of a verdazyl radical with a carboxylate substituent renders the radical highly soluble in water, thereby permitting the aqueous synthesis of Ni(II) and Co(II) verdazyl complexes which have been structurally and magnetically characterized. 相似文献
25.
Lemaire J Boissel P Heninger M Mauclaire G Bellec G Mestdagh H Simon A Le Caer S Ortega JM Glotin F Maitre P 《Physical review letters》2002,89(27):273002
The first example of direct structural characterization of polyaromatic ions by coupling a Fourier transform ion cyclotron resonance mass spectrometer with an infrared free-electron laser is presented. Measurement of the IR spectra of selectively prepared ionic reactive intermediates is allowed by the association of the high peak power and wide tunability of the laser with the flexibility of the spectrometer, where several mass selection and ion reaction steps can be combined, as demonstrated in the case of iron cation complexes of hydrocarbons. The present experimental setup opens the way to understanding chemical reaction paths. 相似文献
26.
F. Herlemont M. Lyszyk J. Lemaire Ch. Lambeau A. Fayt 《Journal of Molecular Spectroscopy》1979,74(3):400-408
Fifty Doppler-broadened absorption lines of ethylene have been measured within large profiles CO2 or N2O lase lines. These laser lines are produced by a high pressure waveguide laser and have a full width between 200 and 900 MHz. Eleven absorption lines, the more intense ones, have been assigned to the ν7 band of C2H4. The other absorption lines must belong to hot bands or to the ν7 band of H212C13CH2. 相似文献
27.
D. Bordeaux J. Lajzerowicz-Bonneteau R. Briere H. Lemaire A. Rassat 《Magnetic resonance in chemistry : MRC》1973,5(1):47-52
The low temperature phase structure of the nitroxide radical 2,2,6,6-tetramethyl piperidin-1-oxyl (Tanane) is isomorphic of 2,2,6,6-tetramethyl-4-piperidinol-1-oxyl (Tanol). An ESR study of single crystals yielded the principal values and position of principal axes of the ? tensor in these two radicals. The major significant differences observed in Tanol are a moderate decrease in the gxx, gyy and gzz values, and a deviation of the principal axes situated in the molecular mirror plane from the N? O bond and π-orbital, respectively (8° ± 2°). The intermolecular hydrogen bond is probably responsible for this fact. 相似文献
28.
S. Nagamiya L. Anderson W. Brückner O. Chamberlain M.-C. Lemaire S. Schnetzer G. Shapiro H. Steiner I. Tanihata 《Physics letters. [Part B]》1979,81(2):147-150
Inclusive proton spectra, as well as two-particle correlations, resulting from collisions between energetic nuclei have been measured. Protons associated with large momentum transfers show exponential-type energy distributions having a decay constant about (70–90 MeV)?1. For light-mass targets a strong two-particle correlation has been observed, which is kinematically consistent with quasi-elastic pp scatterings. 相似文献
29.
Mauclaire G Lemaire J Boissel P Bellec G Heninger M 《European journal of mass spectrometry (Chichester, England)》2004,10(2):155-162
MICRA, a compact Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer is described. The amount of miniaturisation in this device, based on a 1.24 T permanent magnet, remains compatible with genuine FT-ICR performance and analytical power in the mass range 2-1000 m/z, with a mass resolving power of 73,000 at mass 132. A first application of the transportability is the repetitive coupling of MICRA with a large-scale source of IR photons, the free electron laser CLIO. 相似文献
30.
This paper investigates the integration of the employee timetabling and production scheduling problems. At the first level, we manage a classical employee timetabling problem. At the second level, we aim at supplying a feasible production schedule for a set of interruptible tasks with qualification requirements and time-windows. Instead of hierarchically solving these two problems as in the current practice, we try here to integrate them and propose two exact methods to solve the resulting problem. The former is based on a Benders decomposition while the latter relies on a specific decomposition and a cut generation process. The relevance of these different approaches is discussed here through experimental results. 相似文献