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171.
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Arylated anthraquinones were prepared by Suzuki–Miyaura reactions of the bis(triflates) of various 1,3-(dihydroxy)anthraquinones. While the reactions of the bis(triflates) of parent 1,3-(dihydroxy)anthraquinone and of 2-chloro-1,3-di(hydroxy)anthraquinone proceeded with very good site-selectivity, the corresponding reactions of the bis(triflate) of 2-fluoro-1,3-diarylanthraquinones were not site-selective, which was explained based on the π-donating effect of the fluorine atom. 相似文献
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Viktor O. Iaroshenko Satenik Mkrtchyan Ashot Gevorgyan Marcelo Vilches-Herrera Dmitri V. Sevenard Alexander Villinger Tariel V. Ghochikyan Ashot Saghiyan Vyacheslav Ya. Sosnovskikh Peter Langer 《Tetrahedron》2012,68(11):2532-2543
3-Nitrochromone reacts with electron-rich aminoheterocycles (in glacial acetic acid at reflux) and anilines (in a mixture of DMF and TMSCl at 100–140 °C) to give a variety of hetero(carbo)annulated 3-nitropyridines. The reaction, involving a formal [3+3] cyclocondensation, proceeds in high yields and appears not to be influences greatly by the nature of the 1,3-C,N-dinucleophile as seen from the thorough scope study. The synthetic utility of the products was demonstrated by their conversion into the corresponding 3-aminopyridine derivatives. An NMR study and X-ray crystallographic analysis are reported. 相似文献
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Water adsorbed on Ni(1 1 1) forms an ordered, hydrogen bonded ice structure with a (2√7 × 2√7)R19° unit cell. The 2√7 wetting structure forms as islands and persists up to saturation of the first layer. Adsorption of a fraction of a monolayer more water into a second layer destroys the 2√7 registry and creates a disordered ice film. Gas adsorption measurements indicate that the wetting layer is completely covered by a second layer of water before thicker multilayer ice forms. As the second layer is completed the film orders to form an incommensurate crystalline ice film with a hexagonal LEED pattern, oriented to the Ni close packed rows. This ordered, incommensurate structure persists as the ice multilayer grows thicker. 相似文献
180.
Omer Andac Yildiray Topcu Veysel T. Yilmaz William T.A. Harrison 《Journal of chemical crystallography》2000,30(12):767-771
The crystal structure of trans-bis(monoethanolamine)bis(saccharinato)nickel(II), [Ni(C7H4NO3S)2(C2H7NO)2], has been determined from X-ray diffraction data. The metal complex is monoclinic, with a = 11.0555(5), b = 8.9103(4), c = 11.3890(5) Å, = 105.0230(10)°, Z = 2, and space group P21/c
. The structure consists of individual molecules. Two monoethanolamine molecules and two saccharinate anions coordinate the nickel atom forming a distorted octahedron. The monoethanolamine molecules act as a bidentate ligand and form five-membered trans chelate rings, which constitute the plane of the coordination octahedron, while two saccharinate ions behave as a monodentate ligand occupying the axial positions. Intermolecular hydrogen bonds link the molecules to form a three-dimensional infinite structure. 相似文献