共查询到20条相似文献,搜索用时 31 毫秒
1.
Yan Zhao Juan Gu Shao Ming Chi Yong Cun Yang Hong You Zhu Rong Huang Yu Fei Wang 《Journal of solution chemistry》2009,38(4):417-428
The binding behavior of three aromatic diamino-bridged bis(β-cyclodextrin)s (2–4) with four bile salts {cholate (CA), deoxycholate (DCA), glycocholate (GCA) and taurocholate (TCA)} has been investigated
at 25 °C in a phosphate buffer (pH=7.20) by fluorescence and 2D NMR spectroscopy. The results indicate that these bis(β-cyclodextrin)s act as fluorescent sensors. From the ROESY spectra, it is deduced that the phenyl moieties of bis(β-cyclodextrin)s 2–4 are partially self included in the cyclodextrin cavity, and are not expelled from the cavity upon complexation with bile
guests. Owing to the cooperative host-tether-guest binding mode in which the linker and guest are co-included in the two cyclodextrin
cavities, these bis(β-cyclodextrin)s significantly enhance the binding ability and selectivity as compared with the native β-cyclodextrin 1. Possessing suitable tether length, bis(β-cyclodextrin) 3 gives the highest K
S values, ranging up to 39,900 mol⋅L−1, for complexation with CA. The complex stability constants are discussed from the viewpoint of multiple recognitions between
host and guest. 相似文献
2.
Luciana P. Fernandes W. P. Oliveira J. Sztatisz I. M. Szilágyi Cs. Novák 《Journal of Thermal Analysis and Calorimetry》2009,95(3):855-863
Inclusion complexes of Lippia sidoides essential oil and β-cyclodextrin were obtained by slurry method and its solid powdered form was prepared using spray drying.
The influence of the spray drying, as well as the different essential oil:β-cyclodextrin ratio on the characteristics of the
final product was investigated. With regard to the total oil retention 1:10 mass/mass ratio as optimal was found between the
essential oil and β-cyclodextrin.
Thermoanalytical techniques (TG, EGD, TG-MS) were used to support the formation of inclusion complex and to examine their
physicochemical properties after accelerated storage conditions. It may be assumed that the thermal properties of the complexes
were influenced not only by the different essential oil/ β-cyclodextrin ratio but also by the storage conditions. In the aspect
of their thermal stabilities, complex prepared with 1:10 m/m ratio (essential oil:β-cyclodextrin) was the most stable one. 相似文献
3.
Zhi-zhong Wang Wei Jiao Guang-yun He Run-hua Lu 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):79-81
Abstract A simple method for the straightforward regioselective synthesis of 2,3-mannoepoxy-β-cyclodextrin, which is a valuable precursor for further functionalization of β-cyclodextrin, is achieved under aqueous conditions without any organic solvents at a moderate yield.
Graphical abstract
相似文献
4.
The retention of epigallocatechin gallate (EGCG) on oligo-β-cyclodextrin (oligo-β-CD) bonded agarose chromatographic media was investigated. NMR spectroscopy in solution showed that the EGCG immerses into
the β-CD cavity. The association constant calculated by NMR titration was used to estimate a retention factor which accurately
reflected chromatographic behaviour. This correlation suggests that oligo-β-CD forms inclusion complexes with EGCG via the same mechanism as monomeric β-CD.
Revised: 14 March and 25 April 2006 相似文献
5.
Study on the Association Phenomenon of Cyclodextrin to Porphyrin J-aggregates by NMR Spectroscopy 总被引:1,自引:0,他引:1
Hui Li Ma Jian Jun Wu Wen Juan Liang Jian Bin Chao 《Journal of inclusion phenomena and macrocyclic chemistry》2007,58(3-4):221-226
The nuclear magnetic resonance (NMR) spectroscopy demonstrated that the inclusion complexes of meso-tetrakis- (p-sulfonatophenyl) porphyrin (TPPS) with β-, Hydroxypropyl-β- and Methyl-β-cyclodextrin (β-, HP-β- and Me-β-CD) are formed,
which resulted in the dissociation of TPPS J-aggregates efficiently under certain acidity. There are no significant differences
in binding affinities and basic complexation mechanisms between TPPS and β-cyclodextrin (β-CD) or hydroxypropyl-β-cyclodextrin
(HP-β-CD), i.e. porphyrin is included through the wide side of the cavity of β-CD or HP-β-CD. Alternatively, porphyrin is
included through the narrow side of the Me-β-CD cavity. 相似文献
6.
Xiu-Kui Qu Lan-Ying Zhu Ling Li Xi-Lian Wei Feng Liu De-Zhi Sun 《Journal of solution chemistry》2007,36(5):643-650
As a continuation of our previous investigation, interactions between cyclodextrin (β-CD), γ-cyclodextrin (γ-CD) and alkyl trimethylammonium bromides in aqueous solutions have been studied with titration calorimetry and 1H NMR at 298.15 K. The results are discussed in terms of the amphiphilic interaction of CD with surfactants and the iceberg
structure formed by water molecules existing around the hydrophobic tail of surfactant molecules. The stoichiometry of the β-CD–surfactant system is 1:1 whereas that of the γ-CD–surfactant system is 1:2. The corresponding formation enthalpy (negative) of the complexes of the two systems decreases
with an increase in the number of carbon atoms (n) in hydrophobic chain of surfactant molecule, C
n
H2n+1, whereas the entropy increases with the enlargement of n. 相似文献
7.
Khaldoun A. Al-Sou’od 《Journal of solution chemistry》2008,37(1):119-133
Phase solubility diagrams (PSDs) and molecular mechanical (MM) modeling were used to study the complexation of hydrocortisone
(HCor) with β-cyclodextrin (β-CD). The phase solubility profile of HCor with β-CD was classified as the Bs-type. PSDs revealed a six-fold increase in HCor water solubility upon addition of 7 mmol⋅dm−3
β-CD concentration (solubility in 7 mmol⋅dm−3 of β-CD/solubility in water). The thermodynamic study shows the complexation process is exothermic, with a ΔH value of −5.28 kJ⋅mol−1. MM calculations were used to predict the optimal stoichiometry of the complex formed as well as the possible orientations
of HCor inside the β-CD cavity. The complexes prepared were analyzed through chemical analysis, which provides evidence for the 1:1 complexation
of HCor/β-CD.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
8.
Keiichi Motoyama Hidetoshi Arima Fumitoshi Hirayama Kaneto Uekama 《Journal of inclusion phenomena and macrocyclic chemistry》2006,56(1-2):75-79
The effects of 2,6-di-O-methyl-3-O-acetyl-β-cyclodextrins (DMA-β-CyD) with various degrees of substitution (DS) of an acetyl group of 1.5, 3.8, 6.3 and 7, which are abbreviated to DMA2-β-CyD, DMA4-β-CyD, DMA6-β-CyD and DMA7-β-CyD, respectively, on murine macrophage activation and endotoxin shock induced by lipopolysaccharide (LPS) were examined. Of four DMA-β-CyDs used in the present study, cytotoxicity of DMA-β-CyDs in RAW264.7 cells, a murine macrophage-like cell line, decreased with an increase in the DS values of DMA-β-CyD, and DMA7-β-CyD had no cytotoxicity on RAW264.7 cells up to 100 mM. DMA2-β-CyD and DMA7-β-CyD at the concentration of 5 mM had greater inhibitory effects on nitric oxide (NO) production in RAW264.7 cells stimulated with LPS than DMA4-β-CyD and DMA6-β-CyD. In addition, these inhibitory effects of DMA2-β-CyD and DMA7-β-CyD were concentration-dependent. In the in vivo study, all of the mice died within 12 h after intraperitoneal administration of the solution containing LPS and d-galactosamine. When 100 mM DMA7-β-CyD was concomitantly administered with both LPS and d-galactosamine intraperitoneally in mice, the survival rate significantly increased, but DMA4-β-CyD and DMA6-β-CyD did not. In conclusion, we revealed that DS values of DMA-β-CyDs strikingly affect not only the cytotoxic activity but also the inhibitory effects of LPS-induced NO production in RAW264.7 cells and fatality of endotoxin shock mice induced by LPS and d-galactosamine. These results suggest the potential use of DMA7-β-CyD as an antagonist of LPS-induced endotoxin shock. 相似文献
9.
A. Amini V. Barclay T. Rundlöf S. Jönsson A. Karlsson T. Arvidsson 《Chromatographia》2006,63(3-4):143-148
This paper reports the determination of caffeine, ephedrine and pseudo-ephedrine in a dietary product by two rapid and simple
methods utilising capillary electrophoresis (CE). The solutes were extracted from the product using 0.2 M HCl and determined
by CE with background electrolytes containing 7.5% highly sulfated-β-cyclodextrin (7–11 sulfate groups per β-CD molecule) at pH 2.5 and pH 7.6. Determination of ephedrine and pseudo-ephedrine was accomplished at pH 2.5 with the anode
at the detection side of the capillary whereas caffeine was quantified at pH 7.6 with a normal electrophoresis polarity mode.
Triethanolamine was added to the running buffer at pH 2.5 in order to reverse the electroosmotic flow (EOF) and thereby speed
up the separation of ephedrine and pseudo-ephedrine.
Revised: 18 November 2005 and 2 January 2006 相似文献
10.
Twelve cardiac glycosides and aglycons were isolated from Strophanthus kombe seeds. Of these, eight were identified as cymarin, K-strophanthin-β, K-strophanthoside, periplocymarin, 17α-strophadogenin, erysimin (= helveticoside), erysimoside, and neoglucoerysimoside.
Four glycosides, preliminarily designated Sk-x, Sk-y, Sk-z, and Sk-20, were new. Their chemical structures were established
as 3β-O-β-D-glucopyranosyl-5β,14β,16β-trihydroxy-19-oxo-17α-card-20(22)enolide (17α-strophadogenin-3-O-β-D-glucoside), 3β-O-β-D-cymaropyranosyl-5β,14β,16β-trihydroxy-19-oxo-17α-card-20(22)enolide (17α-strophadogenin-3-O-β-D-cymaroside), 3β-O-β-D-cymaropyranosyl-4′-O-β-D-glucopyranosyl-6″-O-β-D-glucopyranosyl-5β, 14β,16β-trihydroxy-19-oxo-17α-card-20(22)enolide (17α-strophadogenin-3-O-strophanthotrioside), and 3-O-β-D-digitoxopyranosyl-4′-O-β-D-glucopyranosyl-6″-O-β-D-glucopyranosyl-5β,14β, 19-trihydroxy-card-20(22)enolide (strophanthidol-3-O-gentiobiosyldigitoxoside), respectively.
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Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 156–159, March–April, 2006. 相似文献
11.
T. Stalin B. Shanthi P. Vasantha Rani N. Rajendiran 《Journal of inclusion phenomena and macrocyclic chemistry》2006,55(1-2):21-29
Effect of solvents, buffer solutions of different pH and β-cyclodextrin (β-CD) on the absorption and fluorescence spectra of p-aminobenzoic acid (pABA) have been investigated. The inclusion complex of pABA with β-CD is investigated by UV-visible, fluorimetry, semiempirical quantum calculations (AM1), 1H NMR and Scanning Electron Microscope (SEM). The thermodynamic parameters (ΔH, ΔG and ΔS) of the inclusion process are also determined. The experimental results indicated that the inclusion processes is an exothermic and spontaneous. The large Stokes shift emission in solvents with pABA are correlated with different solvent polarity scales. The increase in the excited dipole moment values suggest that pABA molecule is more polar in the S1 state. Solvent and β-CD studies indicates intramolecular charge transfer in pABA is less than ortho and meta isomers. Acidity constants for different prototropic equilibria of pABA in the S0 and S1 states are calculated. β-Cyclodextrin studies shows that pABA forms a 1:1 inclusion complex with β-CD. A mechanism is proposed to explain the inclusion process. 相似文献
12.
Several host–guest inclusion compounds of eugenol as a guest molecule and cyclodextrins (α-,β-,γ-CD) and heptakis (2,6-di-O-methyl)-β-cyclodextrin (DMβ-CD) as hosts were investigated in the solid state and in aqueous solution. The one-to-one solid inclusion compounds of eugenol
and β-CD or γ-CD were prepared, but those of eugenol with α- or DMβ-CD were not obtained under the same condition. However, the UV-visible absorption spectroscopy data indicated that the liquid
guest could form a 1:1 inclusion compound with all four hosts respectively in aqueous solution. The two solid inclusion compounds
were characterized by powder X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TG), differential
scanning calorimetry (DSC) and nuclear magnetic resonance (NMR). The association constants (K), calculated from the modified Benesi–Hidebrand equation, of eugenol with α-, β-, γ- and DMβ-CD is 4.95 × 104, 3.96 × 105, 1.47 × 105 and 9.33 × 104 mol−1 dm3, respectively. 相似文献
13.
Xiaodong Jia Xingzeng Zhao Ming Wang Yu Chen Yunfa Dong Xu Feng 《Chemistry of Natural Compounds》2008,44(6):692-695
Two new coumarin biosides, tert-O-β-D-apiofuranosyl-(1→6)-O-β-D-glucopyranosyl-byakangelicin (1) and 2′-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranosyl-peucedanol (2), were isolated from the fresh roots of Angelica dahurica. The structures of the new compounds were elucidated on the basis of spectral analysis.
Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 561–563, November–December, 2008. 相似文献
14.
Khaldoun A. Al-Sou’od Mohammad B. Zughul Adnan A. Badwan 《Journal of solution chemistry》2006,35(10):1377-1388
Phase solubility diagrams (PSDs) at 25 ∘C and molecular mechanical (MM) modeling were used to study the aqueous complexation of some 2H- and 3H-indole derivatives with β-cyclodextrin (β-CD). Among the 3H-indole derivatives investigated in this work, indole-3H-butyric acid forms the most stable 1:1 complex of the B
s
-type PSD, whereas shorter chain derivatives form soluble 1:1 complexes (A
L
-type PSDs) with their stability increasing as the chain length increases. Indole-2 carboxylic acid forms highly stable 1:1 and 1:2 complexes, with the lower-order complex reaching saturation first (B
s
-type PSD). MM modeling indicates that the stability of the complex is highly correlated with the flexibility of the 3H-indole hydrocarbon chain, which yields a better geometrical fit within the β-CD cavity resulting from different hydrophilic interactions. These interactions are represented in the H-bonding of the carboxyl group with the primary hydroxyl group network that is situated at the narrow rim of the cavity, and also by a favorable interaction of the aromatic ring with the hydroxyl group network at the other rim. 相似文献
15.
The synthesis of α-amino-β-keto-esters (β-oxo dipeptides) was studied. Corresponding α-amino-β-ketoesters were prepared from BOC-(L)-Valine and BOC-(L)-isoleucine by coupling with (D,L)-threonine hydrochloride and oxidation
with Dess-Martin periodinane (DMP) with a total yield of 48% and 38%, respectively.
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Translated from Chemistry Online, 2007, 70(10): 793–796 [译自: 化学通报] 相似文献
16.
A new binary chiral selector system effective for the enantioselective extraction of racemic mandelic acid is presented. While
L-dipentyl tartrate and β-cyclodextrin had a very low enantioselectivity as single selectors, a preferential extraction of D-mandelic acid to the organic phase was found in the binary selector system. Using decanol as organic solvent and pH of a
phoshate buffer equal to 2.3, the distribution coefficients of D-and L-mandelic acids as high as 14.9 and 7.0, respectively, and the enantioselectivity value of 2.1 were found at optimum concentration
of β-cyclodextrin. 相似文献
17.
N. N. Sidamonidze L. K. Janiashvili R. O. Vardiashvili R. A. Gakhokidze 《Chemistry of Natural Compounds》2006,42(2):127-128
A new synthesis of certain lactam-containing N-glycosides was developed. 2,3,4,6-Tetra-O-acetyl-β-D-gluco(galacto)pyranosylcaprolactams and 2,3,4,6-tetra-O-acetyl-β-D-gluco(galacto)pyranosylpyrrolidones were synthesized by condensation at room temperature of acetobromoglucose and acetobromogalactose
with ɛ-caprolactams and α-pyrrolidone.
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Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 105–106, March–April, 2006. 相似文献
18.
B. B. Semenov K. A. Novikov V. V. Kachala V. N. Azev 《Chemistry of Natural Compounds》2006,42(5):582-584
The Pictet-Spengler reaction involving β-phenyltryptamine was shown to be diastereo-specific with formation primarily of the (1S*,4R*) diastereomer of 4-phenyl-1-(2-thienyl)-2,3,4,9-tetrahydro-1H-β-carboline, a compound with potential GABA-receptor activity.
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Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 468–470, September–October, 2006. 相似文献
19.
Mahmoud M. Al Omari Mohammad B. Zughul J. Eric D. Davies Adnan A. Badwan 《Journal of inclusion phenomena and macrocyclic chemistry》2007,58(3-4):227-235
The complexation of terfenadine (Terf) with β-cyclodextrin (β-CD) in solution and solid state has been investigated by phase solubility diagram (PSD), differential scanning calorimetry
(DSC), powder X-ray diffractometry (PXD) and proton nuclear magnetic resonance (1H-NMR). The PSD results indicated that the salt saturation with the buffer counter ion (citrate−2, H2PO4−1 and Cl−1 ions) of Terf (pK
a = 9.5) and the hydrophobic effect play in tandem to increase the value of the complex formation constant (K11) measured at different conditions of pH, ionic strength, buffer type and buffer concentration. The correlation of the free
energy of complex formation (ΔG11) with the free energy of inherent solubility of Terf (ΔGSo) obtained by changing the pH, ionic strength and buffer concentration was used to measure the contribution of the hydrophobic
effect (desolvation) to complex formation. The hydrophobic effect was found to constitute 57.8% of the driving force for complex
stability, while other factors including specific interactions contribute −13.4 kJ/mol. 1H-NMR spectra of Terf–citrate and Terf–HCl salts gave identical chemical shift displacements (ΔΔ) upon complexation, thus
indicating that the counter anions are positioned somewhere outside of the β-CD cavity. DSC, XRPD and 1H-NMR proved the formation of solid Terf/acid/β-CD ternary complexes. 相似文献
20.
Jun-hua Shi Yuxun Zhou Ming-lei He Jian Jin Yi-chuan Xiao Jun-hua Xiao Dong-zhi Wei 《Chemistry of Natural Compounds》2006,42(3):325-327
A novel compound, biotinylated 18β-glycyrrhetinic acid (BGA), was synthesized. It is a compound of 18β-glycyrrhetinic acid linked with biotin.
Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 266–267, May–June, 2006.
An erratum to this article is available at . 相似文献