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利用6-(4-卤代苯基)-3(2H)-哒嗪酮的银盐(2)与2,3,4,6-四-O-乙酰基-1-溴-1-脱氧-α-D-吡喃葡萄糖(3)发生Koenigs-knorr反应,
合成了3-O-(2,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖-1-基)-6-(4-卤代苯基)哒嗪(4),4用干燥的氨气在0℃~-5℃下处理脱乙酰基保护基得相应的3-O-(β-D-吡喃葡萄糖-1-基)-6-(4-卤代苯基)哒嗪(5).其结构经元素分析,IR及1H
NMR证实. 相似文献
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利用6-(4-卤代苯基)-3(2H)-哒嗪酮的银盐(2)与2,3,4,6-四-O-乙酰基-1-溴-1-脱氧-α-D-吡喃葡萄糖(3)发生Koenig’s-knorr反应,合成了3-0-(2,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖-1-基)-6-(4-卤代苯基)哒嗪(4),4用干燥的氨气在0℃~-5℃下处理脱乙酰基保护基得相应的3-O-(β-D-吡喃葡萄糖-1-基)-6-(4-卤代苯基)哒嗪(5)。其结构经元素分析,IR及1H NMR证实。 相似文献
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从仿刺参(Apostichopus japonicus Selenka)乙醇提取物中分离得到2个新的海参烷型皂苷类化合物,通过波谱数据分析并结合理化性质鉴定其分别为3β-O-{2-O-[3-O-甲基-β-D-吡喃葡萄糖-(1→3)-β-D-吡喃木糖-(1→4)-β-D-吡喃喹诺糖]-4-O-[β-D-吡喃葡萄糖]-β-D-吡喃木糖}-海参烷-7(8),25(26)-二烯-16-酮(化合物1,命名为Holotoxin E1)和3β-O-{2-O-[3-O-甲基-β-D-吡喃葡萄糖-(1→3)-β-D-吡喃木糖-(1→4)-β-D-吡喃葡萄糖]-4-O-[β-D-吡喃葡萄糖-(1→3)-β-D-吡喃葡萄糖]-β-D-吡喃木糖}-海参烷-7(8),25(26)-二烯-16-酮(化合物2,命名为Holotoxin E2).采用CCK-8法考察了包含上述2个新成分在内的共6个海参烷型皂苷对乳腺癌MDA-MB-231细胞和肝癌HepG2细胞的细胞毒活性.结果表明,除Holotoxin E2外,其余5种化合物对MDA-MB-231(I... 相似文献
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在KOH/acetone体系中,4-N-(取代邻羟苯基)亚胺基-5-(4-甲基-1,2,3-噻二唑)-1,2,4-三唑-3-硫酮(3a~3d)与溴-α-D-四乙酰葡萄糖发生Kenigs-Knorr反应,合成了8个未见报道的S(N)-β-D-乙酰葡萄糖苷,其结构经1H NMR、13C NMR、红外光谱及元素分析等确定.目标化合物的生物活性测试结果表明,它们对金黄色葡萄球菌、白色念珠菌和大肠杆菌均显示了较好的抑菌活性,其效果接近或优于对照药物三氯生和氟康唑的抑菌效能.其中,化合物2-N-(2’,3’,4’,6’-O-四乙酰基-β-D-吡喃葡萄糖基)-4-N-(3,5-二溴邻羟苯基)亚胺基-5-(4-甲基-1,2,3-噻二唑)-1,2,4-三唑-3-硫酮(4d)及3-S-(2’,3’,4’,6’-O-四乙酰基-β-D-吡喃葡萄糖硫基)-4-N-(3,5-二溴邻羟苯基)亚胺基-5-(4-甲基-1,2,3-噻二唑)-1,2,4-三唑(5d)具有较强的抑菌活性. 相似文献
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手性胶束的不对称诱导作用不对称苯偶姻缩合反应 总被引:2,自引:0,他引:2
胶束体系是模拟酶的简单模型之一。手性胶束对反应有手性诱导作用。在表面活性剂(1R,2S)-(-)-N-十二烷基-N-甲基麻黄素溴化物和(1R,2S)-(-)-N-十六烷基-N-甲基麻黄素溴化物形成的胶束体系中进行的苯偶姻缩合反应,生成了光学活性的α-羟基酮。 相似文献
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《有机化学》2020,(6)
以2,3,4-三-O-苯甲酰基-α-L-鼠李糖三氯乙酰亚胺酯、2,4-二-O-苯甲酰基-α-L-鼠李糖对甲氧基苯基苷、2,3,4,6-四-O-苯甲酰基-β-D-葡萄糖三氯乙酰亚胺酯和2,3-O-异丙叉基-α-L-鼠李糖对甲氧基苯基苷为原料,采用[2+2]偶联策略,对巴西固氮螺菌(Azospirillum brasilense type strain Sp246)表面脂多糖的四糖重复单元α-L-鼠李糖-(1→3)-α-L-鼠李糖-(1→3)-[β-D-葡萄糖-(1→4)]-α-L-鼠李糖结构进行全合成.在合成单元子的反应中,采用硅胶负载高氯酸(HClO_4-SiO_2)作为酸性催化剂,三乙基硅基作为选择性保护基,简单高效地构建全保护的四糖.该合成路线步骤短,试剂种类少,反应后处理简单,以L-鼠李糖为原料计算,目标化合物四糖总收率达到23%,化合物结构经~1H NMR和~(13)C NMR、HRMS和IR确证. 相似文献
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Hidetaka Noritomi Shogo Tamai Hiroaki Saito Satoru Kato 《Colloid and polymer science》2009,287(4):455-459
The extraction of methyl orange or methylene blue from an aqueous phase to an organic phase of reverse micelles of alkyl glucosides
was investigated. Dodecyl glucoside, a biodegradable and biocompatible surfactant, was employed as a kind of alkyl glucosides,
since a stable Winsor II system consisting of the water-in-oil type microemulsion and aqueous phases was formed when an organic
solution containing dodecyl glucoside was contacted with an aqueous solution. The water content in the reverse micellar organic
phase increased with an increase in the concentration of dodecyl glucoside. The extraction ratio of dyes also increased with
increasing the concentration of dodecyl glucoside. Furthermore, the extraction ratio of dyes was dramatically dependent upon
the pH of an aqueous phase and temperature. 相似文献
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Musnicki WJ Lloyd NW Phillips RJ Dungan SR 《Journal of colloid and interface science》2011,356(1):165-175
The gradient diffusion of ionic sodium dodecyl sulfate micelles in agarose gel was investigated at moderate concentrations above the CMC. Of particular interest were the effects of micelle, gel, and sodium chloride concentration on the micelle diffusivity. Holographic interferometry was used to measure the gradient diffusion coefficient at three sodium chloride concentrations (0, 0.03, 0.10 M), three gel concentrations (0, 1, 2 wt%), and several surfactant concentrations. Time-resolved fluorescence quenching was used to measure aggregation numbers both in solution and gel. The micelle diffusivity increased linearly with surfactant concentration at the two larger sodium chloride concentrations and all gel concentrations. In general, the strength of this effect increased with decreasing sodium chloride concentration and increased with gel concentration. This behavior is evidence of decreasing micelle-micelle electrostatic interactions with increasing sodium chloride concentrations, and increasing excluded volume effects and hydrodynamic screening with increasing gel concentration, respectively. The only exception was at 0.1M sodium chloride and 2 wt% agarose, which showed a slight reduction in the slope compared to 1 wt% agarose. It was found that the concentration effect is quite strong for charged solutes: at a NaCl concentration of 0.03 M in a 2% agarose gel, in a solution with 3% SDS micelles by volume, the micelle diffusion coefficient is doubled relative to its value in the same gel at infinite dilution. The extrapolated, infinite-dilution diffusion coefficients and the rate at which the micelle diffusivity increased with surfactant concentration were compared with predictions of previously published theories in which the micelles are treated as charged, colloidal spheres and the gel as a Brinkman medium. The experimental data and theoretical predictions were in good agreement. 相似文献
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Neves AC Valente AJ Burrows HD Ribeiro AC Lobo VM 《Journal of colloid and interface science》2007,306(1):166-174
The effect of TbCl3 on the aggregation processes of the anionic surfactants sodium decyl sulfate (SDeS) and sodium dodecyl sulfate (SDS) has been investigated. Electrical conductivity data, combined with Tb(III) luminescence measurements suggest that the formation of micelles involving TbCl3 and SDS occurs at concentrations below the critical micelle concentration (cmc) of the pure surfactants; the formation of these mixed aggregates was also monitored by light scattering, which indicates that the addition of TbCl3 to surfactant concentration at values below the pure surfactant cmc results in a much greater light scattering than that found with pure sodium alkylsulfate surfactant micelles. This phenomenon is dependent upon the alkyl chain length of the surfactant. With Tb(III)/DS-, complexes are formed with a cation/anion binding ratio varying from 3 to 6, which depends upon the initial concentration of Tb(III). This suggests that the majority of the cation hydration water molecules can be exchanged by the anionic surfactant. When the carbon chain length decreases, interactions between surfactant and Tb(III) also decrease, alterations in conductivity and fluorescence data are not so significant and, consequently, no binding ratio can be detected even if existing. The surfactant micellization is dependent on the presence of electrolyte in solution with apparent cmc being lower than the corresponding cmc value of pure SDS. 相似文献
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The lytic interactions of a series of alkyl glucosides (alkyl chain lengths ranging from C8 to C12) with liposomes formed by a mixture of lipids modeling the stratum corneum (SC) lipid composition were investigated. The
surfactant-to-lipid molar ratios (Re) and the normalized bilayer/aqueous phase partition coefficients (K) were determined by monitoring the changes in the static light-scattering (SLS) of the system during solubilization. The
fact that the free surfactant concentrations were always similar to their critical micelle concentrations indicates that the
liposome solubilization was mainly ruled by the formation of mixed micelles. At the two interaction levels studied (100 and
0% SLS) the nonyl glucoside showed the highest ability to saturate and to solubilize liposomes (lowest Re values), whereas
the dodecyl glucoside showed the highest degree of partitioning into liposomes or affinity with these structures (highest
K values). Comparison of the data for octyl glucoside with that reported for the interaction of this surfactant with phosphatidylcholine
(PC) liposomes shows that whereas the SC lipid liposomes were more resistant to the action of this surfactant (higher Re values),
its degree of partitioning into SC bilayers was both in the saturation and solubilization of liposomes similar to that exhibited
in PC vesicles (similar K values).
Received: 27 November 2000/Accepted: 19 February 2001 相似文献
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Electric properties of mixed anionic-nonionic surfactant systems in aqueous solutions above the CMC have been studied in terms of pNa values, electrical conductivities, and dielectric constants; these systems are sodium 3, 6, 9-trioxaicosanoate (ECL) — alkyl polyoxyethylene ethers (CmPOE; m=12, 14, 16, and 18). The degree of ionic dissociation of mixed micelle increases with increasing the number of carbon atoms of the alkyl group in the nonionic surfactant. The electrical conductivity increases with increasing the alkyl chain length in the nonionic surfactant, in spite of the increase of the activation energy for conduction. The size of mixed micelles also increases with increasing alkyl chain length. This may be attributed to the fact that the mixed micelle is formed more easily by a nonionic surfactant including long alkyl chains than for one having shorter alkyl chains. 相似文献
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The formation of micelles and the composition and concentration of sub-micellar components of surfactant solutions was studied for sodium lauryl sulfate (SLS), alkyl polyethoxy (average of 7 EO) sulfate (AEOS 7EO) and mixtures of these two anionic surfactants both above and below the critical micelle concentrations (c.m.c). Radiolabeled surfactant was added to the solutions to follow the concentration and identity of the components. To separate micelles from sub-micellar components, an Amicon microfiltration apparatus containing either a 2, 5, or 30 thousand molecular weight cut off membrane was used. Results using a hydrophobic fluorescent probe demonstrated minimal disruption of the micelles during separation. Separations for single surfactants showed breaks in the concentration curves at the c.m.c. The observed sub-micellar composition and concentration were evidence of non-ideal behavior. Concentration dependence and surfactant selectivity in micellization (the “micro c.m.c.”phenomena) is described. This previously undocumented behavior reveals that the compositions of micelles and the sub-micellar phase for mixed surfactant systems do not reflect the composition of the original solution mixture. 相似文献
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The solubility of a water-insoluble dye, Sudan Red B, in aqueous sodium halide solutions of tetradecyl-, cetyl-, and stearyltrimethylammonium halides has been measured at different surfactant and salt concentrations, and the dependence of solubilization properties on alkyl chain length has been discussed with reference to the micelle size and shape. At low ionic strengths where only spherical micelles exist, the solubilization power of micellar surfactant slightly increases with increasing the ionic strength, but it sharply increases at high ionic strengths above the threshold value of sphere-rod transition. However, the solubilization power becomes independent of the ionic strength, if their rodlike micelles are sufficiently long. The solubilization capacity increases linearly with increasing the molecular weight, almost independent of counterion species, but the rod-like micelle has a higher solubilization capacity than the spherical micelle. The solubilization capacity is larger for a surfactant with longer alkyl chain, indicating that the dye is solubilized more readily in a larger hydrophobic core. The solubilized dye is situated in a rodlike micelle of alkyltrimethylammonium halides, on average, 4.5–7.5 nm apart from each other. 相似文献
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W. A. G. R. Al-Shahib A. S. Dunn 《Journal of polymer science. Part A, Polymer chemistry》1978,16(3):677-684
There is evidence in the literature that the rates of emulsion polymerization increase by a large factor as the alkyl chain length increases for a homologous series of surfactants. However, the area occupied by a surfactant molecule in a saturated monolayer at the polystryene/water interface is independent of chain length for alkyl sulfates so that, on the basis of Gardon's theory, equal rates of polymerization would be expected when equal concentrations of surfactants are used. There is a large increase in the number of polymer latex particles formed and in the rate of emulsion polymerization as the surfactant concentration is increased through the critical micelle concentration; this accounts for the large increases reported, because the lower members of the homologous series are below their critical micelle concentrations in most of the published studies. When a common concentration is chosen that is above the critical micelle concentration even for the lowest member of the series, only a relatively small increase in latex particle number and rate of emulsion polymerization with alkyl chain length of the surfactant is observed. This is attributable to an increase in the concentration of surfactant micelles. Good agreement with Gardon's theory is obtained when the concentration of micellar surfactant is used instead of the total surfactant concentration. 相似文献
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Adsorption of the anionic surfactant sodium dodecyl sulfate on a C18 column under micellar and high submicellar conditions in reversed‐phase liquid chromatography
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C. Ortiz‐Bolsico M. J. Ruiz‐Angel M. C. García‐Alvarez‐Coque 《Journal of separation science》2015,38(4):550-555
Micellar liquid chromatography makes use of aqueous solutions or aqueous‐organic solutions containing a surfactant, at a concentration above its critical micelle concentration. In the mobile phase, the surfactant monomers aggregate to form micelles, whereas on the surface of the nonpolar alkyl‐bonded stationary phases they are significantly adsorbed. If the mobile phase contains a high concentration of organic solvent, micelles break down, and the amount of surfactant adsorbed on the stationary phase is reduced, giving rise to another chromatographic mode named high submicellar liquid chromatography. The presence of a thinner coating of surfactant enhances the selectivity and peak shape, especially for basic compounds. However, the risk of full desorption of surfactant is the main limitation in the high submicellar mode. This study examines the adsorption of the anionic surfactant sodium dodecyl sulfate under micellar and high submicellar conditions on a C18 column, applying two methods. One of them uses a refractive index detector to obtain direct measurements of the adsorbed amount of sodium dodecyl sulfate, whereas the second method is based on the retention and peak shape for a set of cationic basic compounds that indirectly reveal the presence of adsorbed monomers of surfactant on the stationary phase. 相似文献
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Tamoto Y Segawa H Shirota H 《Langmuir : the ACS journal of surfaces and colloids》2005,21(9):3757-3764
Solvation dynamics of the fluorescence probe, coumarin 102, in anionic surfactant, sodium alkyl sulfate (C(n)H(2n+1)SO(4)Na; n = 8, 10, 12, and 14), and cationic surfactant, alkyltrimethylammonium bromide (C(n)H(2n+1)N(CH(3))(3)Br; n = 10, 12, 14, and 16), micelle solutions have been investigated by a picosecond streak camera system. The solvation dynamics in the time range of 10(-10)-10(-8) s is characterized by a biexponential function. The faster solvation time constants are about 110-160 ps for both anionic and cationic micelle solutions, and the slower solvation time constants for sodium alkyl sulfate and alkyltrimethylammonium bromide micelle solutions are about 1.2-2.6 ns and 450-740 ps, respectively. Both the faster and the slower solvation times become slower with longer alkyl chain surfactant micelles. The alkyl-chain-length dependence of the solvation dynamics in both sodium alkyl sulfate and alkyltrimethylammonium bromide micelles can be attributed to the variation of the micellar surface density of the polar headgroup by the change of the alkyl chain length. The slower solvation time constants of sodium alkyl sulfate micelle solutions are about 3.5 times slower than those of alkyltrimethylammonium bromide micelle solutions for the same alkyl-chain-length surfactants. The interaction energies of the geometry optimized mimic clusters (H(2)O-C(2)H(5)SO(4)(-) and H(2)O-C(2)H(5)N(CH(3))(3)(+)) have been estimated by the density functional theory calculations to understand the interaction strengths between water and alkyl sulfate and alkyltrimethylammonium headgroups. The difference of the slower solvation time constants between sodium alkyl sulfate and alkyltrimethylammonium bromide micelle solutions arises likely from their different specific interactions. 相似文献