共查询到9条相似文献,搜索用时 15 毫秒
1.
O. A. Fedorova Yu. P. Strokach A. V. Chebun’kova T. M. Valova S. P. Gromov M. V. Alfimov V. Lokshin A. Samat 《Russian Chemical Bulletin》2006,55(2):287-294
Complex formation of Mg2+, Ba2+, and Pb2+ perchlorates with 3,3-diphenyl-3H-benzo[f]chromenes containing aza-and diaza-18-crown-6-ether or morpholine fragments was studied. The strong influence of the metal
cations on the spectral characteristics of these organic ligands and on the kinetic of photochromic transformations was found.
The results obtained were explained by the formation of carbonyl-“ capped” complexes of various structures.
Faculte des Sciences de Luminy, Universite de la Mediterranee, UMR 6114 CNRS, 13288 Marseille, France.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 280—287, February, 2006. 相似文献
2.
E. O. Chukhadzhyan A. R. Gevorkyan El. O. Chukhadzhyan K. G. Shakhatuni F. S. Kinoyan G. A. Panosyan 《Chemistry of Heterocyclic Compounds》2004,40(1):29-36
The ability of the 4-hydroxy-2-butynyl group to participate as ,-unsaturated fragment in base-catalyzed intramolecular cyclization was established. 2,2-Dialkyl-4-hydroxymethylbenzo[f]isoindolinium and 2,2-dialkyl-4-hydroxymethylisoindolinium salts were obtained by the cyclization of dialkyl(4-hydroxy-2-butynyl)(3-phenylpropargyl)- or dialkyl(4-hydroxy-2-butynyl)(3-alkenylpropargyl)ammonium salts. 相似文献
3.
Summary By condensation of 2,2-difluoro-4-methyl-benzo[d]-1,3,2-2H-dioxaborines (12) with cyano acetic acid derivatives in presence of weak bases, 3-cyano-4-methyl-benzo[b]pyran-2-ones (13) or their 3-cyano-4-methyl-benzo[b]pyran-2-imine precursors (14) are available in satisfactory yields.
Zur Kondensation von 2,2-Difluor-4-methyl-benzo[d]-1,3,2-2H-dioxaborinen mit Cyanessigsäure- Derivaten. Bildung und Umwandlung von 3-Cyano-4-methyl-benzo[b]pyran-2-onen und ihrer 2-Imino-Vorstufen
Zusammenfassung Durch Kondensation von 2,2-Difluor-4-methyl-benzo[d]-1,3,2-2H-dioxaborinen (12) mit Cyanessigsäure-Derivaten in Gegenwart von Hilfsbasen entstehen in befriedigenden Ausbeuten 3-Cyan-4-methyl-benzo[b]pyran-2-one (13) oder ihre 3-Cyan-4-methyl-benzo[b]pyran-2-imino-Vorstufen (14).相似文献
4.
5.
Oxidation of 3-substituted 4-R-6-nitro-1-phenyl-1H-indazoles and benzo[d]isoxazoles (R = Ph, CH2CO2Me) gave the corresponding sulfones treatment of which with PhSH—K2CO3 in N-methylpyrrolidone results in replacement of only the RSO2 group in position 4 with the 6-NO2 group remaining intact, contrary to the known sequence of nucleophilic substitution for meta-arranged nucleofuges. 相似文献
6.
Gholam Hossein Rounaghi Massoumeh Mohajeri Shima Ashrafi Hoda Ghasemi Saman Sedaghat Maryam Tavakoli 《Journal of inclusion phenomena and macrocyclic chemistry》2007,58(1-2):1-6
Conductance measurements are reported for nickel(II), cupper(II), silver(I) and cadmium(II), salts in acetonitrile (AN)–dimethylformamide
(DMF) binary solvents containing macrocyclic ligand, 1,10-dibenzyl-1,10-diaza-18-crown-6 (DBDA18C6) at different temperatures.
The changes in molar conductance caused by addition of DBDA18C6 to solutions were analyzed by non-linear least squares to
give stability constants of 1:1 metal cation–DBDA18C6 complexes. The results show that the stabilities of the complexes are
sensitive to solvent composition and in some cases the sequence of stabilities is changed with changing the composition of
the mixed solvents. The values of thermodynamic quantities (ΔH°c and ΔS°c) for formation of DBDA18C6-Ni2+, DBDA18C6-Cu2+, DBDA18C6-Ag+ and DBDA18C6-Cd2+ complexes were obtained from temperature dependence of the stability constants and the results show that the values of ΔH°c and ΔS°c for these complexes are sensitive to the nature and composition of AN–DMF binary solutions, but they do not vary monotonically
with the solvent composition. 相似文献
7.
E. O. Chukhadzhyan A. R. Gevorkyan A. A. Khachatryan El. O. Chukhadzhyan G. A. Panosyan 《Chemistry of Heterocyclic Compounds》2006,42(9):1151-1157
p-Bis{3-[N,N-dialkyl-N-(4-hydroxybut-2-ynyl)ammonio]prop-2-ynyl}benzene dichloride in the presence of catalytic amounts of
aqueous alkali is subject to a double intramolecular cyclization forming benzo[5,6;5′,6′-a,c]di(2,2-dialkyl-4-hydroxymethyl)isoindolinium
dichloride in 40–42% yield. Simultaneously an intramolecular recyclization takes place with the formation of dialkyl(6-dialkylaminomethyl-7,9,10,12-tetrahydro-8,11-dioxadicyclopenta[c,g]phenanthren-1-ylmethyl)amines
in 7–9% yield. The same compounds are obtained in 70–72% yield by the recyclization of benzo[5,6;5′,6′-a,c]di(2,2-dialkyl-4-hydroxymethyl)isoindolinium
dichlorides under conditions of aqueous alkaline degradation.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1329–1335, September, 2006. 相似文献
8.
A. Yu. Lepeshkin K. F. Turchin E. G. Gal’pern I. V. Stankevich K. A. Lyssenko V. S. Velezheva 《Russian Chemical Bulletin》2007,56(7):1447-1455
Based on the results of studies of the deuterium exchange and dehydration of 4-hydroxy-Δ2-thiazolines and 2-R-4-acetyl-8b-hydroxy-3a,8b-dihydro-4H-thiazolo[5,4-b]indoles containing the α-methylene (methine) unit at the C(2) atom, the mechanism of dehydration of these compounds generated
as intermediates in the Hantzsch synthesis of thiazoles and 2-R-4-acetyl-4H-thiazolo[5,4-b]indoles was proposed. This mechanism includes an additional step of the formation of the corresponding Δ3-thiazolines. According to the results of quantum chemical calculations, this is energetically more favorable than the dehydration
in terms of the commonly accepted mechanism. In some cases, an acidic medium impedes the dehydration of 4-hydroxy-Δ2-thiazolines or their cyclic analogs. The proposed mechanism provides an explanation for the empirical data on the differences
in the reactivities of both thioamides and α-haloketones, which have remained unexplained in terms of the commonly accepted
mechanism. The spontaneous thiazole synthesis is virtually impossible starting from thioamides of aromatic or heteroaromatic
acids and α-haloketones bearing electron-withdrawing α′ substituents or cyclic bromoindoxyl-type haloketones. In the thiazole
synthesis from these starting components, it is expedient to perform dehydration under basic catalysis.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1394–1402, July, 2007. 相似文献
9.
Ma?gorzata Jó?wiak 《The Journal of chemical thermodynamics》2004,36(12):1129-1138
The thermodynamic functions of complex formation of benzo-15-crown-5 ether with sodium cation in {(1 − x)DMA + xH2O} at T = 298.15 K have been calculated. The equilibrium constants of complex formation of benzo-15-crown-5 ether with sodium cation have been determined by conductivity measurements. The enthalpic effect of complex formation has been measured by calorimetric method at T = 298.15 K. The complexes are enthalpy stabilized and entropy destabilized. A simple model has been proposed to describe the relationship between the thermodynamic functions of complex formation of crown ethers with sodium cation and the structural and energetic properties of the mixed water-organic solvent. The linear enthalpy-entropy relationship for complex formation is also presented. The solvation enthalpy of the complex in {(1 − x)DMA + xH2O} is discussed. 相似文献