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991.
992.
Jun Ni Yi‐Zhi Li Wen‐Bin Qi Yong‐Jiang Liu Hui‐Lan Chen Zhi‐Lin Wang 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(8):o470-o472
The title compound, 3,3′‐(4‐pyridylimino)dipropanenitrile, C11H12N4, has a twofold axis and consists of a pyridine ring head and two cyanoethyl tails, the three groups being linked by an N atom. The planar geometry around the amino N atom suggests conjugation with the π‐system of the pyridine ring. The molecules are stacked in a layer structure via relatively weak to very weak intermolecular C—H⃛π and C—H⃛N hydrogen‐bond interactions. 相似文献
993.
Shan‐Bao Qiao Chang‐Mei Jiao Qing‐Feng Xu Yong Zhang Bao‐Long Li Jian‐Ping Lang 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(11):m465-m466
The reaction of CuCN and KCN with (NH4)2[WS4] followed by cation exchange with PPh4Br produced the title compound, (C24H20P)2[Cu2WS4(CN)2]·CH3CN·H2O or (PPh4)2[(NC)Cu(μ‐S)2W(μ‐S)2Cu(CN)]·MeCN·H2O. In the structure of the dianion, [(NC)Cu(μ‐S)2W(μ‐S)2Cu(CN)]2−, the WS4 moiety acts as a bidentate ligand that binds two CuCN groups, thus forming a slightly bent WCu2 core with approximate D2d symmetry. The W—Cu distances are in the range 2.6463 (6)–2.6545 (6) Å. 相似文献
994.
Effects of external fields such as magnetic field and boundary conditions on supramolecular structure, molecular arrangement and the texture of the ethyl-cyanoethyl cellulose cholesteric liquid crystalline solutions were investigated. It was found that the molecules of (E-CE)C are oriented to perpendicular to the magnetic field and the diamagnetic anisotropy of (E-CE)C is negative. With homeotropic anchoring boundary condition, the molecules are aggregated with focal-conics arrangement the molecules are aggregated with planar arrangement with homogeneous anchoring boundary condition. The effects of the external field on the orientation of the cholesteric phase were influenced by the concentration of the solution because the twist power of the cholesteric was varied with the concentration. And the effects are also restrains by the surface tension of the interphase. 相似文献
995.
Three new pregnane glycosides, cynatroside A ( 1 ), cynatroside B ( 2 ), and cynatroside C ( 3 ), isolated from the roots of Cynanchum atratum (Asclepiadaceae), were characterized as 7β‐{[O‐α‐L ‐cymaropyranosyl‐(1→4)‐O‐β‐D ‐digitoxopyranosyl‐(1→4)‐β‐D ‐oleandropyranosyl]oxy}‐3,4,4a,4b,5,6,7,8,10,10a‐decahydro‐6α‐hydroxy‐4b‐ methyl‐2‐(2‐methyl‐3‐furyl)phenanthren‐1(2H)‐one ( 1 ), 7β‐{[O‐β‐D ‐cymaropyranosyl‐(1→4)‐O‐α‐L ‐diginopyranosyl‐(1→4)‐β‐D ‐cymaropyranosyl]oxy}‐3,4,4a,4b,5,6,7,8,10,10a‐decahydro‐2,6α‐dihydroxy‐4b‐methyl‐2‐(2‐methyl‐3‐furyl)phenanthren‐1(2H)‐one ( 2 ), and 7β‐{[O‐α‐L ‐cymaropyranosyl‐(1→4)‐O‐β‐D ‐digitoxopyranosyl‐(1→4)‐β‐L ‐cymaropyranosyl]oxy}‐3,4,4a,4b,5,6,7,8,10,10a‐decahydro‐2,6α‐dihydroxy‐4b‐methyl‐2‐(2‐methyl‐3‐furyl)phenanthren‐1(2H)‐one ( 3 ), respectively. In addition, ten known constituents were identified, i.e., cynascyroside D ( 4 ), glaucoside C ( 5 ), glaucoside D ( 6 ), atratoside A ( 7 ), 2,4‐dihydroxyacetophenone ( 8 ), 4‐hydroxyacetophenone ( 9 ), syringic acid ( 10 ), azelaic acid ( 11 ), suberic acid ( 12 ), and succinic acid ( 13 ). Among these compounds, 1 – 4 significantly inhibit acetylcholinesterase activity. 相似文献
996.
Yu Liu Yong Chen Shi-Zhao Kang Li Li Chun-Hua Diao Heng-Yi Zhang 《Journal of inclusion phenomena and macrocyclic chemistry》2003,47(1-2):91-95
Two novel benzo-15-crown-5 tethered β-cyclodextrins 1 and 2have been synthesized by coupling substituted benzo-15-crown-5 with correspondingβ-cyclodextrin derivatives. Their inclusion complexation behavior withrepresentative guests, such as cyclohexanol, cyclohexane carboxylic acid, cyclohexaneacetic acid, sodium cyclohexane carboxylate, and potassium cyclohexane carboxylate,was investigated in aqueous solution by means of fluorescence spectrometry. As compared with parent β-cyclodextrin, benzo-15-crown-5 tethered β-cyclodextrins 1–2 display significantly enhanced molecular binding abilities and selectivities towards model substrates, especially towards substrates containing alkali-metal cations. These results indicate that, bearing two recognition sites in a single molecule, these supramolecular architectures can strongly enhance the molecular binding ability of parent β-cyclodextrin by the cooperative binding of the β-cyclodextrin cavity and the crown ether moiety. Possessing a shorter linker, crown ether-β-cyclodextrin 2 shows much higher binding affinity with guest molecules than crown ether-β-cyclodextrin 1, which may be attributed to the binding size and molecular multiple recognition behavior between host and guest. 相似文献
997.
Yong‐Qian Wu David C. Limburg Douglas E. Wilkinson Gregory S. Hamilton 《Journal of heterocyclic chemistry》2003,40(1):191-193
A mild and efficient synthesis of five‐ and six‐membered nitrogen containing heterocyclic compounds, in which di(imidazole‐1‐yl)methanimine serves as a one‐carbon source, is reported. 相似文献
998.
The reaction of prop‐1‐ene‐1,3‐sultone 1 with a variety of nitrile oxides 3 afforded novel [3+2] cycloaddition products 4 in good yield. The cycloaddition reaction achieved excellent regioselectivity. 相似文献
999.
You-An Xiao Zhi-Qiang Wang Xue-Min Wang Yi Hui Yong Ling Xin-Yang Wang Li-Qin He 《中国化学快报》2013,24(8):727-730
Novel 2-aminoimidazolone derivatives were synthesized.Most compounds displayed strong anticancer activities against human carcinoma cells in vitro.Compounds 8a,8b and 8j exhibited optimal activity superior to 5-FU in most cancer cells tested.Especially,the lC50s of 8b(12.6-21.5μmol/L) against five tumor cells were 1 -4 fold less than those of 5-FU(18.4-56.1μmol/L) in vitro.Furthermore,comp以ound 8b could induce SMMC-7721 cell apoptosis in a dose-dependent manner.Therefore,our novel findings may provide a new framework for the design of new 2-aminoimidazolone derivatives for the treatment of cancer. 相似文献
1000.