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211.
Mohamed M. El-Kerdawy Ali A. El-Emam Hussein I. El-Subbagh Elie Abushanab 《Monatshefte für Chemie / Chemical Monthly》1990,121(1):45-50
Summary A new series of thiophenic isosters of thioxanthones, namely: 2-substituted-4H-thieno[2,3-b][1]benzothiopyran-4-ones and 5-substituted-2-nitro-8-methyl-4H-thieno[2,3-b][1]benzothiopyran-4-ones were synthesized as potential schistosomicidal agents. The synthesized compounds were characterized by their1H-NMR data.
Synthese von substituierten 4H-Thieno[2,3-b][1]benzothiopyran-4-onen als mögliche schistosomicide Wirkstoffe
Zusammenfassung Es wurde eine neue Serie von thiophenischen Isosteren des Thioxanthons, nämlich 2-substituierte 4H-Thieno[2,3-b][1]benzothiopyran-4-one und 5-substituierte 2-Nitro-8-methyl-4H-thieno[2,3-b][1]benzothiopyran-4-one als potentielle schistosomicide Wirkstoffe synthetisiert. Die synthetisierten Verbindungen wurden mittels ihrer1H-NMR Daten charakterisiert.相似文献
212.
Graziella Tocco Michela Begala Giovanna Delogu Carmen Picciau Gianni Podda 《Tetrahedron letters》2004,45(37):6909-6913
In the presence of catalytic amount of indium(III) chloride (10 mol %), 2,2′-dihydroxybiphenyl and bis(2-hydroxyphenyl)methane react quickly, without using any solvent, with ketones or β-keto esters possessing at least one hydrogen atom in α to the ketone-carbonyl group, to afford some new dibenzo(d,f)(1,3)dioxepines and some 12H-dibenzo(d,g)(1,3)dioxocin derivatives, respectively. 相似文献
213.
Soluble fluoro-polyimides have been synthesized by reacting of a fluorine-containing aromatic dianhydride, 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, with aromatic diamine to yield poly(amic acid)s which were then cyclized to yield polyimide by chemical imidization method. The polyimides have excellent solubility both in strong bipolar solvents, such as NMP and DMAc, and in common organic solvents, such as THF and dioxane, etc. The glass transition temperature of these polyimides were determined by DSC and ranged from 281 to 289 °C. Thermogravimetric analysis indicated that these polyimides have good thermal stability with initial thermal decomposition temperature of 520-526 °C. The polyimide asymmetric membranes were prepared by phase inversion method and the inner structure was observed by method of SEM. The pervaporation properties of the prepared polyimides asymmetric membranes for n-heptane/thiophene mixtures were investigated at 40-77 °C and the permeation flux and the sulfur enrichment factor of the polyimide membranes are in the range of 0.56-1.68 kg/m2 h and 3.12-2.24, respectively. The result demonstrated that the pervaporation method could be very effective method for desulfurization by polyimides asymmetric membranes with ultrathin skin. 相似文献
214.
The synthesis and the characterization of some new aluminum complexes with bidentate 2-pyrazol-1-yl-ethenolate ligands are described. 2-(3,5-Disubstituted pyrazol-1-yl)-1-phenylethanones, 1-PhC(O)CH2-3,5-R2C3HN2 (1a, R = Me; 1b, R = But), were prepared by solventless reaction of 3,5-dimethyl pyrazole or 3,5-di-tert-butyl pyrazole with PhC(O)CH2Br. Reaction of 1a or 1b with (R1 = Me, Et) yielded N,O-chelate alkylaluminum complexes (2a, R = R1 = Me; 2b, R = But, R1 = Me; 2c, R = Me, R1 = Et). Compound 1a was readily lithiated with LiBun in thf or toluene to give lithiated species 3. Treatment of 3 with 0.5 equiv of MeAlCl2 or AlCl3 yielded five-coordinated aluminum complexes [XAl(OC(Ph)CH{(3,5-Me2C3HN2)-1})2] (4, X = Me; 5, X = Cl). Reaction of 5 with an equiv of LiHBEt3 generated [Al(OC(Ph)CH{(3,5-Me2C3HN2)-1})3] (6). Complex 6 was also obtained by reaction of 3 with 1/3 equiv of AlCl3. Treatment of 5 with 2 equiv of AlMe3 yielded complex 2a, whereas with an equiv of AlMe3 afforded a mixture of 2a and [Me(Cl)AlOC(Ph)CH{(3,5-Me2C3HN2)-1}] (7). Compounds 1a, 1b, 2a-2c and 4-6 were characterized by elemental analyses, NMR and IR (for 1a and 1b) spectroscopy. The structures of complexes 2a and 5 were determined by single crystal X-ray diffraction techniques. Both 2a and 5 are monomeric in the solid state. The coordination geometries of the aluminum atoms are a distorted tetrahedron for 2a or a distorted trigonal bipyramid for 5. 相似文献
215.
Synthesis of 12-deoxyroyleanone, cryptoquinone, 11,14-dihydroxy-8,11,13-abietatrien-7-one, and related derivatives from dehydroabietic acid 总被引:1,自引:0,他引:1
Yoh-ichi Matsushita Yoshihisa Iwakiri Satoru Yoshida Kazuhiro Sugamoto Takanao Matsui 《Tetrahedron letters》2005,46(21):3629-3632
Naturally occurring abietane quinones and hydroquinone, namely, 12-deoxyroyleanone (1a), cryptoquinone (4a), and 11,14-dihydroxyabieta-8,11,13-trien-7-one (5a), together with the epimers of tryptoquinones D (2) and F (3), were first synthesized from dehydroabietic acid (6). 相似文献
216.
Maria Bocheska Maria Hoffmann Urszula Lesiska Emilia Luks Wanda Radecka-Paryzek 《Tetrahedron》2005,61(52):12307-12313
New compounds: 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(3-diisopropoxyphosphorylpropoxy)calix[4]arene (1) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(3-methoxyethoxyphosphorylpropoxy)calix[4]arene (2) were synthesized and their ionophoric properties in ion-selective membrane electrodes were studied in comparison with already described by us 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(3-diethoxyphophorylpropoxy)calix[4]arene (3). Complexes of 1 with calcium(II), lanthanum(III), europium(III) and gadolinium(III) nitrates were prepared in direct reaction of the ligand and appropriate metal salts. They were characterized by spectral data (IR, UV/Vis, luminescence, NMR, ESI-MS) and elemental analysis. The similarity in complexing behavior of the (dialkoxyphosphoryl)propoxy-calix[4]arenes toward calcium and some lanthanides was observed. 相似文献
217.
218.
Phenyltrichlorosilane was hydrolyzed both ifi. toluene and in ether from which two kinds of prepolymers were obtained with different structures, molecular weights, and molecular weight distributions. Polymers were prepared from the prepolymers in various polymerization conditions. The ladderlike, branched, and crosslinked structures formed under different polymerization conditions were characterized by means of FTIR, ~1H and ~(29)Si-NMR, and elemental analysis. Azeotropic distillation of solvents and H_2O formed during polymerization was found useful in removing H_2O from the system and high molecular weight products with perfect ladderlike structure were obtained. 相似文献
219.
本文报道了四种2-亚甲基-1,3-二氧己烷类单体:4-甲基-2-亚甲基-1,3-二氧己烷(Ⅱ)、4,6-二甲基-2-亚甲基-1,3-二氧己烷(Ⅳ)、5,5-二甲基-2-亚甲基-1,3-二氧己烷(Ⅵ)和5,5-二乙基-2-亚甲基-1,3-二氧己烷(V Ⅲ)的合成以及自由基开环聚合。结果表明,上述单体在聚合过程中出现异构化开环现象。Ⅲ和Ⅳ的甲基位置在环上氧原子的α-碳原子上时,显示对异构化反应的影响比Ⅵ及Ⅷ的甲基和乙基在β-碳原子上时更显著。上述现象与异构化开环形成仲碳自由基中间体的倾向更大有关。 Ⅳ在苯溶液中及过氧化二叔丁基存在下,120℃反应,得到全部是聚-δ-戊内酯骨架结构的聚合物。提出了一种合成聚-δ-戊内酯类链结构的聚酯的新的途径和方法。 相似文献
220.
A phosphate-based epoxy resin for flame retardance: synthesis, characterization, and cure properties 总被引:2,自引:0,他引:2
A phosphorus-containing oligomer, bis(3-hydroxyphenyl) phenyl phosphate (BHPP), was synthesized through the reaction of phenyl dichlorophosphate and 1,3-dihydroxybenzene, and characterized by elemental analysis, Fourier transform IR spectroscopy, and 1H NMR and 31P NMR spectroscopy. Consequently, the phosphate-based epoxy resins with a phosphorus content of 1 and 2 wt % were prepared via the reaction of diglycidyl ether of bisphenol-A with BHPP and bisphenol-A, and were confirmed with Fourier transform IR spectroscopy and gel permeation chromatography. Phenolic melamine, Novolak, and dicyanodiamide were used as curing agents to prepare the thermoset resins with the control and the phosphate-based epoxy resins. Thermal properties and thermal degradation behavior of these thermoset resins were investigated by using differential scanning calorimetry and thermogravimetric analysis. The thermoset resins cured with phenolic melamine exhibited higher glass-transition temperatures than the other cured resins owing to the high rigidity of their molecular chain. Thermogravimetric analysis studies demonstrated that the decomposition temperatures of the thermoset resins cured with Novolak were higher than those of the others. A synergistic effect from the combination of the phosphate-based epoxy resin and the nitrogen-containing curing agent can result in a great improvement of the flame retardance for their thermoset resins. 相似文献