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91.
    
A number of 17 sulfonamides (SNs) determination in porcine tissues using two new materials including Enhanced Matrix Removal for Lipid (EMR‐L) and Oasis PRiME hydrophilic‐lipophilic balance (HLB), and the conventional liquid–liquid extraction with n‐hexane (LLE) sample preparation methods were evaluated and compared. Samples were extracted uniformly with acidified acetonitrile and cleaned up by the three sample preparation methods, and then, analytes were further separated by ultrahigh‐performance liquid chromatography (UHPLC) and detected by a triple quadrupole mass spectrometry (MS/MS) or a quadrupole‐time‐of‐flight tandem mass spectrometry (Q‐TOF/MS). The results showed that the matrix effects from the EMR‐L and HLB were significantly lower than that from LLE, suggesting that these two new materials are superior to n‐hexane in the precipitation of proteins and the adsorption of lipids. Moreover, the recoveries of 17 SNs were quantified by the matrix‐matched calibration curve at spiked level of 5, 10, and 20 μg/kg, and 97.0% of the results satisfied method validation requirements. The samples cleaned up by EMR‐L and HLB achieved the highest average recovery in liver and kidney with high moisture content, and muscle which is high in fat, respectively. In addition, Q‐TOF/MS could play a good role in aided verification based on the result of repeated validation test. In summary, either combination of approaches could be used to achieve monitoring purposes; it is still worthwhile to adopt a specific sample preparation method and MS detector for the quantification in a specific matrix.  相似文献   
92.
Molecular hybridization approach is a promising structural modification tool to design new chemical entities (NCEs) by mimicking two different pharmacophoric units into one scaffold to enhance the biological properties. With this aim, combretastatin-A4 acids were integrated with sulfonyl piperazine scaffolds as a one molecular platform and evaluated for their in vitro antiproliferative activity against a panel of human cancer lines cell lines namely, lung (A549), mouse melanoma (B16F10), breast (MDA MB-231and MCF-7) and colon (HCT-15) by MTT assay. Amongst which the compound (E)-3-(4-Chlorophenyl)-1-(4-((4-chlorophenyl)sulfonyl)piperazin-1-yl)-2-(3,4,5-trimethoxyphenyl)prop-2-en-1-one ( 5 ab ) displayed significant IC50 values in the range of 0.36 to 7.08 μm against the selected cancer cell lines. Moreover, 5 ab was found to be the most potent member of this series with IC50 0.36±0.02 μm . Further investigations revealed that the compound 5 ab displayed significant inhibition of tubulin assembly with IC50 5.24±0.06 μm and molecular docking studies also disclosed the binding of 5 ab effectively in CA4 binding space at the colchicine binding site. The flow cytometric analysis demonstrated that the compound 5 ab caused cell cycle arrest at G2/M phase in A549 cells. Compound 5 ab induced apoptosis in A549 cells which was further evaluated by different staining assays such as DAPI and AO which undoubtedly speculated, the induction of apoptosis. To study the anti-migration with 5 ab , cell migration/scratch wound assay was performed and the extent of apoptosis was studied by Annexin-V, including mitochondrial potential by JC-1 staining.  相似文献   
93.
    
A new series of quinoline-based benzenesulfonamides (QBS) were developed as potential carbonic anhydrase inhibitors (CAIs). The target QBS CAIs is based on the 4-anilinoquinoline scaffold where the primary sulphonamide functionality was grafted at C4 of the anilino moiety as a zinc anchoring group (QBS 13a–c); thereafter, the sulphonamide group was switched to ortho- and meta-positions to afford regioisomers 9a–d and 11a–g. Moreover, a linker elongation approach was adopted where the amino linker was replaced by a hydrazide one to afford QBS 16. All the described QBS have been synthesized and investigated for their CA inhibitory action against hCA I, II, IX and XII. In general, para-sulphonamide derivatives 13a–c displayed the best inhibitory activity against both cancer-related isoforms hCA IX (KIs = 25.8, 5.5 and 18.6 nM, respectively) and hCA XII (KIs = 9.8, 13.2 and 8.7 nM, respectively), beside the excellent hCA IX inhibitory activity exerted by meta-sulphonamide derivative 11c (KI = 8.4 nM). The most promising QBS were further evaluated for their anticancer and pro-apoptotic activities on two cancer cell lines (MDA-MB-231 and MCF-7). In addition, molecular docking simulation studies were applied to justify the acquired CA inhibitory action of the target QBS.  相似文献   
94.
    
The growing resistance of the influenza virus to widely used competitive neuraminidase inhibitors occupying the active site of the enzyme requires the development of bifunctional compounds that can simultaneously interact with other regulatory sites on the protein surface. When developing such an inhibitor and combining structural fragments that could be located in the sialic acid cavity of the active site and the adjacent 430-cavity, it is necessary to select a suitable linker not only for connecting the fragments, but also to ensure effective interactions with the unique arginine triad Arg118-Arg292-Arg371 of neuraminidase. Using molecular modeling, we have demonstrated the usefulness of the sulfonamide group in the linker design and the potential advantage of this functional group over other isosteric analogues.  相似文献   
95.
    
A series of 14 target benzyl [2-(arylsulfamoyl)-1-substituted-ethyl]carbamates was prepared by multi-step synthesis and characterized. All the final compounds were tested for their ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in vitro, and the selectivity index (SI) was determined. Except for three compounds, all compounds showed strong preferential inhibition of BChE, and nine compounds were even more active than the clinically used rivastigmine. Benzyl {(2S)-1-[(2-methoxybenzyl)sulfamoyl]-4-methylpentan-2-yl}carbamate (5k), benzyl {(2S)-1-[(4-chlorobenzyl)sulfamoyl]-4-methylpentan-2-yl}carbamate (5j), and benzyl [(2S)-1-(benzylsulfamoyl)-4-methylpentan-2-yl]carbamate (5c) showed the highest BChE inhibition (IC50 = 4.33, 6.57, and 8.52 µM, respectively), indicating that derivatives 5c and 5j had approximately 5-fold higher inhibitory activity against BChE than rivastigmine, and 5k was even 9-fold more effective than rivastigmine. In addition, the selectivity index of 5c and 5j was approx. 10 and that of 5k was even 34. The process of carbamylation and reactivation of BChE was studied for the most active derivatives 5k, 5j. The detailed information about the mode of binding of these compounds to the active site of both BChE and AChE was obtained in a molecular modeling study. In this study, combined techniques (docking, molecular dynamic simulations, and QTAIM (quantum theory of atoms in molecules) calculations) were employed.  相似文献   
96.
G. Roshan Deen  L.H. Gan 《Polymer》2006,47(14):5025-5034
‘Stimuli’ responsive copolymers of N-acryloyl-N′-ethyl piperazine (AcrNEP) and methyl methacrylate (MMA) were synthesized by free radical solution polymerization. The copolymers were analyzed as thin films by FTIR spectroscopy. The monomer reactivity ratios were determined by linearization methods of Fineman-Ross (F-R) and Kelen-Tüdös (K-T) giving the results r1 (AcrNEP)=0.58 and r2 (MMA)=0.91 by the F-R method and r1=0.72 and r2=1.08 by the K-T method. The latter r values in turn yielded Q=0.59 and e=−0.12 for AcrNEP. Crosslinked copolymer hydrogels of AcrNEP and MMA with various compositions were prepared in bulk and solution by photo-initiated free-radical polymerization. The gels were dual responsive to pH and temperature. The response to pH was reversible with a response time of 100 min with good reversibility and with no loss in swelling capacity. Water sorption of the gels was investigated gravimetrically and the collective diffusion coefficients were determined at 10, 25, and 50 °C. The water sorption of the gels in water was Fickian. The temperature dependence of the equilibrium water content was studied by the Gibbs-Helmholtz equation. The enthalpy of mixing decreased with an increase in the hydrophilic content (AcrNEP) of the gel. Other parameters such as type and amount of crosslinker, preparative conditions, nature of buffers, and salts were found to influence the swelling behavior.  相似文献   
97.
哌嗪紫外吸收弱,最强峰对应波长处吸光度线性范围窄,因此紫外分光光度法在呱嗪检测中的应用受到了限制。根据哌嗪紫外吸收特点.探讨了对哌嗪水溶液进行紫外分光光波法快速测定的方法.该方法不采用哌嗪紫外吸收最强蜂对应波长作为测定波长,而采用了基线干噪和波段积分等手段对哌嗪紫外吸收光潜进行了数据处理,因此该方法的准确度和精确度得到了保证,回收率实验和精密度实验的结果表明.该方法的准确和精确度良好.  相似文献   
98.
目的 建立超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)同时测定鳗鱼中13种磺胺类、15种喹诺酮类和4种四环素类兽药残留的分析方法。方法 鳗鱼试样采用乙二胺四乙酸二钠(ethylenediaminetetraacetic acid disodium salt, Na2EDTA)-Mcllvaine提取液进行提取, HLB固相萃取柱净化, Waters ACQUITY UPLC BEH C18色谱柱分离, 以0.1%甲酸乙腈和0.1%甲酸水溶液作为流动相进行梯度洗脱; 电喷雾正离子模式下, 以多反应监测(multiple reaction monitoring, MRM)方式采集数据进行定性与定量分析, 外标法定量。结果 磺胺类、喹诺酮类及四环素类药物分别在2~50、2~50、5~100 μg/kg浓度范围内线性相关性良好, 相关系数均大于0.99; 不同加标水平的平均回收率为82.6%~110.2%, 相对标准偏差(relative standard deviations, RSDs)为3.2%~13.9%, 检出限(limits of detection, LODs)和定量限(limits of quantification, LOQs)分别为0.3~2.0 μg/kg和1.0~5.0 μg/kg。结论 本方法快速简便、灵敏可靠, 适合大批量鳗鱼中同时快速对磺胺类、喹诺酮类及四环素类兽药残留进行定性和定量检测。  相似文献   
99.
为了提高西他列汀侧链哌嗪盐酸盐的产率,并简化操作,以三氟乙酸乙酯为原料,经肼解、氧氯化磷环合、乙二胺亲核取代、闭环等反应,制备了3-(三氟甲基)-5,6,7,8-四氢[1,2,4]三唑并[4,3-α]哌嗪盐酸盐。工艺产物收率较高,反应条件温和,操作简单,溶剂回收简单。  相似文献   
100.
    
A new methodology for the synthesis of enantiomerically enriched bicyclic δ‐sultams is described, involving an initial organocatalytic intramolecular aza‐Michael reaction of vinyl sulfonamides bearing a conjugated ketone at a remote position. The resulting Michael adducts were then subjected to an intramolecular conjugate addition over the vinyl sulfone moiety, thus rendering the final bicyclic sultams containing two stereocenters. The key point of this strategy relies on the use of vinyl sulfonamides as both, nitrogen nucleophiles and Michael acceptors. The use of phosphazene‐derived bases avoided the racemization of the intermediate derivatives, rendering 6‐membered ring bicyclic δ‐sultams in enantiomerically enriched manner with a small erosion of enantiopurity. Anyway, after recrystallization, final sultams were obtained in almost enantiomerically pure form. Nevertheless, the enantioselective synthesis of either 5‐membered ring products or benzofused derivatives was found to be out of the scope of our strategy.

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