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61.
Brunella Cappello Clelia Di Maio Maria Iervolino 《Journal of inclusion phenomena and macrocyclic chemistry》2002,43(3-4):251-257
The interactions of Bendazac, a topical non-steroidal anti-inflammatory drug, with-cyclodextrin, hydroxypropyl--cyclodextrin and -cyclodextrinwere investigated to evaluate possibilities to improve the drug's poor water solubilityand eventually to enhance the topical delivery of Bendazac. Phase solubility studiesdemonstrated the ability of the selected cyclodextrins to complex with Bendazac andincrease drug solubility. The amount of solubilized Bendazac increased linearly withthe addition of each cyclodextrin according toAL type plots. 13C-NMR studiesshowed that the Bendazac A-ring was included in the cavity of the three cyclodextrins.The -cyclodextrin was also able to include the B-ring of Bendazac, forminga complex where one drug molecule fitted into two cyclodextrin molecules. Equimolarsolid systems of the drug with each cyclodextrin carrier were prepared using varioustechniques (physical mixing, spray-drying and freeze-drying). The results of differential scanning calorimetry and Fourier transform infrared analysis, performed on the solid systems, demonstrated that freeze-dried and spray-dried products had a high degree of amorphization and agreed with the hypothesis of the existence of drug–cyclodextrin interaction in the solid state. The cyclodextrins tested were able to improve the dissolution of Bendazac. The dissolution profile of the drug was also affected by the physico-chemical properties of each solid system, the freeze-dried products being the most rapidly dissolving forms. 相似文献
62.
V. Ramamoorthy A. Ramasubbu S. Muthusubramanian S. Sivasubramanian 《Journal of inclusion phenomena and macrocyclic chemistry》1999,33(1):69-80
The nitrone is found to be included in the -cyclodextrin cavity in two different stoichiometries viz., 1G : 1H and 1G : 2H – the existence of which is proved by physical methods. The 1G : 2H complex of the nitrone serves as a good potent dipolarophile in the 1,3-dipolar cycloaddition reactions with olefins resulting in rate acceleration and regioselection. 相似文献
63.
T. V. Magdesieva I. I. Kukhareva D. P. Krut'ko G. A. Artamkina K. P. Butin I. P. Beletskaya 《Russian Chemical Bulletin》1994,43(5):881-883
Interaction of the 5-cyclopentadienyldicarbonyliron(II) anion with pentafluorobenzoyl chloride affords C6F5COFe(CO)2Cp, CpFe(CO)2C6F4COFe(CO)2Cp, and CpFe(CO)2C6F4C6F4Fe(CO)2Cp. The reaction products are characterized by1H,13C and19F NMR spectra.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 935–937, May, 1994. 相似文献
64.
A. Lévai 《Monatshefte für Chemie / Chemical Monthly》1995,126(11):1245-1251
Summary 3-Aroyl-4-aryl-2-pyrazolines (21–40) have been synthesized by the reaction of ,-unsaturated ketones (1–20) with diazomethane. These 2-pyrazolines gave -methyl-,-unsaturated ketones (41–46) on thermal denitrogenation.Dedicated to Prof. Dr.F. Sauter on the occasion of his 65th birthday 相似文献
65.
Masaki Tachibana Motohisa Furusawa Nobutoshi Kiba 《Journal of inclusion phenomena and macrocyclic chemistry》1995,22(4):313-329
Extraction of carbazole in heptane was performed at 25±1°C with an aqueous dimethyl sulfoxide (DMSO) medium containing -cyclodextrin (CD) at consecutive concentrations in the range of 0–10 mM. The fluorescence intensity of carbazole remaining in the heptane phase was measured by synchronous scanning fluorimetry. The apparent formation constant (K
f) for a 1:1 carbazole: CD inclusion complex in water-DMSO medium was determined by using a linear plot of the distribution ratio calculated from the fluorescence intensities vs. the -CD concentration. The values thus obtained ranged from 477 M–1 in a 10% v/v DMSO medium to 12.1 M–1 in a 60% v/v medium. Good linear relationships were observed between logK
f and the DMSO concentration ([DMSO]), and also between logK
f and the logarithm of the distribution coefficient (K
d) for carbazole. The formation constant in 100% water was estimated to be approximately 1.0×103 M–1 on the basis of the logK
f vs. [DMSO] and the logK
f vs. logK
d correlations. 相似文献
66.
S. A. Gromilov I. A. Baidina P. A. Stabnikov G. V. Romanenko 《Journal of Structural Chemistry》2004,45(3):476-481
An X-ray diffraction investigation has performed for copper(II) bis-hexafluoroacetylacetonate (Bruker AXS P4 automatic diffractometer, MoK
radiation, t = –25°C). Crystal data for C10H2CuF12O4: a = 5.530(1) Å, b = 6.038(1) Å, c = 11.266(2) Å, = 95.948(3)°, = 101.743(3)°, = 92.298(3)°, space group; P1, V = 365.6(1) Å3, Z = 1, d
calc = 2.169 g/cm3. The square-planar environment of the copper atom (Cu-Oav 1.912 Å, O-Cu-Oav 93°) is completed to bipyramidal by two fluorine atoms of the neighboring molecules, Cu...F 2.71 Å and 2.75 Å.Original Russian Text Copyright © 2004 by S. A. Gromilov, I. A. Baidina, P. A. Stabnikov, and G. V. RomanenkoTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 502–507, May–June 2004. 相似文献
67.
《中国科学B辑(英文版)》2007,(5)
The X-ray crystal structures of (NH4)2(15-crown-5)3[Cu(mnt)2] (1) and (NH4)2(benzo-15-crown-5)4- [Cu(mnt)2]·0.5H2O (2) were determined. Two single crystals are composed of distinct structures of ammonium-crown ether supramolecular cation and [Cu(mnt)2]2? anion. The triple-decker dication in complex 1 and a sandwich dimmer in complex 2 were observed. X-Band EPR studies on the single crystals of both complex 1 and complex 2 have been carried out at room temperature, which revealed that complex 2 showed a perfect hyperfine structure of Cu whereas that of complex 1 could not be observed. The principal values and direction cosines of the principal axes of the g and A tensors were computed by a least-squares fitting procedure. The spin density of Cu(II) was estimated according to the principal values of the A tensors and compared well with the results calculated based on DFT method. 相似文献
68.
Ab initio SCF computations on the intrinsic preferences of the H+, CH
3
+
and C2H
5
+
cations towards the two principal sites of protonation or alkylation on cytosine, N3 or O2, show that this preference undergoes a continuous modification with the increase in size and complexity of the cation. N3 is the preferred site of fixation of H+, O2 the preferred site of C2H
5
+
, while CH
3
+
has no marked preference. The exchange repulsion term of the binding energy appears responsible for the preference of C2H
5
+
for O2.This work was supported by the Ligue Francaise contre le Cancer and the National Foundation for Cancer Research (USA) 相似文献
69.
Ante Graovac Ivan Gutman Oskar E. Polansky 《Monatshefte für Chemie / Chemical Monthly》1984,115(1):1-13
A novel general property of theS- andT-isomers (a concept which has been introduced and elaborated elsewhere1, 2) of alternant hydrocarbons is demonstrated, namely that due to the HMO total -electron energy theS-isomer should always be more stable than theT-isomer. Some other classes of conjugated isomers are also constructed, for which similar inequalities are derived.
Topologischer Effekt bei MO-Energien, 4. Mitt.: Die -Elektronen-Gesamtenergie vonS- undT-Isomeren
Zusammenfassung Es wird allgemein gezeigt, daß bei einemS-T-Isomerenpaar (beschrieben in1, 2) eines alternierenden Kohlenwasserstoffes infolge der HMO -Elektronen-Gesamtenergie dasS-Isomere stets stabiler sein sollte als dasT-Isomere. Weitere Klassen konjugierter Isomere werden konstruiert und ähnliche Ungleichungen angegeben.相似文献
70.
Partitioning adsorption properties of palladium cations on composite supports of MgO/-Al2O3 were explored by IR, TPR and catalytic performance tests for CO oxidation. The experimental results revealed that palladium cations in conventional impregnation was dispersed completely on -Al2O3, when the amount of MgO in the samples was lower than 5%. For the catalysts prepared by double impregnation, part of palladium dispersed on MgO phase due to the complexing action of EDTA. Pd–MgO interaction suppressed the reaction of CO oxidation. 相似文献