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Doris Meuche 《Helvetica chimica acta》1966,49(4):1278-1283
The electronic, infrared and NMR spectra of 6, 6-dialkyl-fulvenes and of 6, 6-poly-methylene-fulvenes are reported. 相似文献
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Regio-isomers, 6A6B, 6A6C, and 6A6D-ditosylates of β-cyclodextrin prepared by the reaction of β-cyclodextrin with tosyl chloride were easily and effectively separated through reversed phase column chromatography and assigned. 相似文献
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Conclusions The reaction of 2,3-di-O-acetylcellulose with N-chloro- or N-iodosuccinimide and triphenylphosphine gave the 6-chloro-6-desoxy- and 6-iodo-6-desoxycellulose acetates with a respective degree of substitution (DS) in halogen of 0.8–1.0 and 0.7. The deacetylation of these compounds gave 6-chloro-6-desoxycellulose (DS 0.8) and 6-iodo-6-desoxycellulose (DS 0.6).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2158–2160, September, 1977. 相似文献
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Strout DL 《The journal of physical chemistry. A》2006,110(22):7228-7231
Recent theoretical studies have identified carbon-nitrogen cages that are potentially stable high energy density materials (HEDM). One such molecule is an N(6)C(6)H(6) cage in which a six-membered ring of nitrogen is bonded to C(3)H(3) triangles on both sides. This molecule is based on the structure of the most stable N(12) cage, with six carbon atoms substituted into the structure. In the current study, several N(6)C(6)H(6) isomers (including the previously studied cage) are examined by theoretical calculations to determine which is actually the most stable. Stability will be evaluated from two points of view: (1) thermodynamic stability of one isomer versus another and (2) kinetic stability of each isomer as determined by the energetics of bond breaking. Density functional theory (B3LYP), perturbation theory (MP2 and MP4), and coupled-cluster theory (CCSD(T)) are used in this study, along with the correlation-consistent basis sets of Dunning. Trends in thermodynamic and kinetic stability are discussed. 相似文献
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Hydrophobically modified polysaccharides that contain amine and amide groups possess valuable features for drug delivery and other applications. These chemical groups are known to play a fundamental role in the biological activity of important polysaccharides. Pullulan is known for its non-toxicity and biocompatibility, therefore, we have applied the versatile Staudinger reaction for the synthesis of regioselectively substituted pullulan derivatives containing amine or amide groups with promise for biomedical applications. The synthesis began with the regioselective bromination of pullulan at C-6 with N-bromosuccinimide and triphenylphosphine, providing 6-bromo-6-deoxy-pullulan, which is soluble in a range of organic solvents and therefore is a dynamic intermediate for the synthesis of other pullulan derivatives. Azide displacement of bromide from 6-bromo-6-deoxy-pullulan esters yielded the corresponding 6-azido-6-deoxy-pullulan esters. Staudinger reduction of these azides efficiently and chemoselectively afforded the corresponding amino- or amidopullulans. 相似文献
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Grzegorz Kasperski Paweŀ Możejko Czesŀaw Szmytkowski 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1997,42(3):187-191
Total absolute cross sections for electron scattering on hexafluorobenzene, C6F6, and sulfur hexafluoride, SF6, molecules, have been measured as a function of impact energy from 0.6 to 250 eV. The total cross section for C6F6 exhibits a very broad peak stretching from 10 to 100 eV with some weak features near 9.5 and 15 eV superimposed on the peak. Apart from the well-known low-energy resonant structures in the SF6 total cross section function, a new weak resonant feature close to 25 eV has been noticed in the present experiment, in accordance with earlier theoretical calculations. 相似文献
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Nobuyuki Tanaka 《Macromolecular Symposia》1996,102(1):429-431
The possibility of porosity control in N6/N66 membranes prepared from N6/N66 blend solutions of calcium chloride – methanol mixture was investigated. For N6/N66 blend solutions at 10 °C and 20 °C, the four-phase structure of solid, gel 1, gel 2 and solution was observed clearly in the pore formation process after adding water on a solution surface. In the boundary part between gel 1 and gel 2, the phase separation of N6 and N66 was predicted. The macroscopic pores of blend membranes prepared at 10°C and 20 °C were almost spherical. 相似文献
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The reactions of chalcogenophosphinites with copper(I) metal salts are shown to yield highly stable, multi-metallic copper-chalcogen based clusters with novel topologies. 相似文献
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Institute for New Chemical Problems, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 2, pp. 7–18, March–April, 1989. 相似文献
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Tsukayama M Wada H Kawamura Y Yamashita K Nishiuchi M 《Chemical & pharmaceutical bulletin》2004,52(11):1285-1289
The palladium-catalyzed coupling reaction of 6-iodoisoflavone, prepared from 3'-iodoacetophenone derivative, with 2-methyl-3-butyn-2-ol gave 6-alkynylisoflavone derivative, which was hydrogenated to give 6-alkylhydroxyisoflavone (luteone hydrate) (2). Dehydration of 2 gave 2',4',5,7-tetrahydroxy-6-prenylisoflavone (luteone) (1). Wighteone hydrate (3) was also synthesized from 6-iodotris(benzyloxy)isoflavone in a similar manner. 6-Alkyl-4'5,7-trihydroxy-coumaronochromone (4) was synthesized by oxidative cyclization of 2 with o-chloranil. 相似文献
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Both the spectra and infrared transition strengths of C6H6 and C6D6 for the C? H stretching overtones up to as high as v = 10 are described in high precision with few parameters (six for the spectra and four for the transition strengths) by the Iachello–Oss algebraic model. The Hamiltonian model is solved in the symmetry adapted bases, which are constructed by the symmetrized boson representation (SBR) technique. The results show that the combination of the algebraic method and SBR technique is a powerful method for describing vibrations of large molecules and high overtones. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 相似文献