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991.
992.
Straightforward Synthesis of 5‐Bromopenta‐2,4‐diynenitrile and Its Reactivity Towards Terminal Alkynes: A Direct Access to Diene and Benzofulvene Scaffolds
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Dr. Nicolas Kerisit Dr. Loïc Toupet Dr. Jean‐Claude Guillemin Dr. Yann Trolez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(16):6042-6047
The high‐yielding synthesis of 5‐bromopenta‐2,4‐diynenitrile (BrC5N) was achieved for the first time. Its reactivity with triisopropylsilylacetylene and triisopropylsilylbutadiyne in the presence of copper and palladium as co‐catalysts and diisopropylamine was evaluated. It revealed an unprecedented cascade reaction leading to a diene in one case and to a benzofulvene in the other case, with a unique structure. Both of them were characterized by X‐ray crystallography, among other techniques. The mechanism of the reaction leading to the diene was investigated experimentally. Theoretical calculations at the DFT level suggest that the mechanism leading to the benzofulvene relies on a hexa‐dehydro Diels–Alder (HDDA)‐type of mechanism. This work constitutes an example of an unanticipated reactivity leading to an important increase of chemical complexity. 相似文献
993.
994.
Shuwen He Peng Li Xing Dai Hong Liu Zhong Lai Dong Xiao Casey C. McComas Chunyan Du Yuehui Liu Jingjun Yin Qun Dang Nicolas Zorn Xuanjia Peng Ravi P. Nargund Anandan Palani 《Tetrahedron letters》2017,58(14):1373-1375
We report a general approach for the synthesis of 5,6-dihydroindolo-naphthyridine ring system via an intramolecular cyclization of the indole NH to an alkene moiety as the key step. 相似文献
995.
Nicolas Charalambakis George Chatzigeorgiou Yves Chemisky Fodil Meraghni 《Continuum Mechanics and Thermodynamics》2018,30(1):1-51
In this paper, a review of papers on mathematical homogenization of dissipative composites under small strains and on the interplay between homogenization procedure and dissipation due to mechanical work is presented. Moreover, a critical survey on the links between mathematical homogenization and computational homogenization is attempted. 相似文献
996.
Automated system measuring triple oxygen and nitrogen isotope ratios in nitrate using the bacterial method and N2O decomposition by microwave discharge
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997.
998.
999.
Julien Rolland Pierre Guillet Jean‐Marc Schumers Nicolas Duhem Véronique Préat Jean‐François Gohy 《Journal of polymer science. Part A, Polymer chemistry》2012,50(21):4484-4493
Interpolymer polyelectrolyte complexes of chitosan (CS) with poly(acrylic acid) homopolymers and polystyrene‐block‐poly(acrylic acid) diblock copolymers were prepared and characterized. The influence of the positive/negative charge balance (charge ratio), pH, and ionic strength were thoroughly studied by dynamic light scattering. The existence of a strong polyelectrolyte effect was also highlighted in this study. Domains of stability, in which nanoparticle sizes are smaller than 100 and 200 nm for complexes of CS with the homopolymer and copolymer, respectively, were identified and confirmed by scanning electron microscopy and atomic force microscopy. The charged nature of the surface of the nanoparticles was evidenced by Zeta potential measurements. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
1000.
Time‐of‐flight secondary ion mass spectrometry imaging of biological samples with delayed extraction for high mass and high spatial resolutions
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