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排序方式: 共有139条查询结果,搜索用时 15 毫秒
31.
Abbas?ShockraviAbbas_Shockravi@yahoo.co.uk" title="Shockravi@saba.tmu.ac.ir Abbas_Shockravi@yahoo.co.uk" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author T.?Samad?Bavili 《Journal of inclusion phenomena and macrocyclic chemistry》2005,52(3-4):223-227
Some new dibenzosulfide macrocyclic diamides (6–12) are synthesized. The macrocyclization process is performed by reaction of the dimethyl ester (5) and diacid chloride (4) with appropriate diamines by two methods. Also the results of two methods are discussed and compared.This revised version was published online in July 2005 with a corrected issue number. 相似文献
32.
A simple and efficient protocol for the chemoselective mono-N-Boc protection of various structurally diverse amines with di-tert-butyl dicarbonate using thioglycoluril as the catalyst is described. The catalyst can be readily separated from the reaction products by simple filtration and recovered for reuse. No competitive side reactions, such as formation of isocyanate, urea, oxazolidinone, and N,N-di-Boc derivatives were observed. 相似文献
33.
Rahul D. Jawarkar Praveen Sharma Neetesh Jain Ajaykumar Gandhi Nobendu Mukerjee Aamal A. Al-Mutairi Magdi E. A. Zaki Sami A. Al-Hussain Abdul Samad Vijay H. Masand Arabinda Ghosh Ravindra L. Bakal 《Molecules (Basel, Switzerland)》2022,27(15)
ALK tyrosine kinase ALK TK is an important target in the development of anticancer drugs. In the present work, we have performed a QSAR analysis on a dataset of 224 molecules in order to quickly predict anticancer activity on query compounds. Double cross validation assigns an upward plunge to the genetic algorithm–multi linear regression (GA-MLR) based on robust univariate and multivariate QSAR models with high statistical performance reflected in various parameters like, fitting parameters; R2 = 0.69–0.87, F = 403.46–292.11, etc., internal validation parameters; Q2LOO = 0.69–0.86, Q2LMO = 0.69–0.86, CCCcv = 0.82–0.93, etc., or external validation parameters Q2F1 = 0.64–0.82, Q2F2 = 0.63–0.82, Q2F3 = 0.65–0.81, R2ext = 0.65–0.83 including RMSEtr < RMSEcv. The present QSAR evaluation successfully identified certain distinct structural features responsible for ALK TK inhibitory potency, such as planar Nitrogen within four bonds from the Nitrogen atom, Fluorine atom within five bonds beside the non-ring Oxygen atom, lipophilic atoms within two bonds from the ring Carbon atoms. Molecular docking, MD simulation, and MMGBSA computation results are in consensus with and complementary to the QSAR evaluations. As a result, the current study assists medicinal chemists in prioritizing compounds for experimental detection of anticancer activity, as well as their optimization towards more potent ALK tyrosine kinase inhibitor. 相似文献
34.
Rahul D. Jawarkar Ravindra L. Bakal Nobendu Mukherjee Arabinda Ghosh Magdi E. A. Zaki Sami A. AL-Hussain Aamal A. Al-Mutairi Abdul Samad Ajaykumar Gandhi Vijay H. Masand 《Molecules (Basel, Switzerland)》2022,27(15)
Using 84 structurally diverse and experimentally validated LSD1/KDM1A inhibitors, quantitative structure–activity relationship (QSAR) models were built by OECD requirements. In the QSAR analysis, certainly significant and understated pharmacophoric features were identified as critical for LSD1 inhibition, such as a ring Carbon atom with exactly six bonds from a Nitrogen atom, partial charges of lipophilic atoms within eight bonds from a ring Sulphur atom, a non-ring Oxygen atom exactly nine bonds from the amide Nitrogen, etc. The genetic algorithm–multi-linear regression (GA-MLR) and double cross-validation criteria were used to create robust QSAR models with high predictability. In this study, two QSAR models were developed, with fitting parameters like R2 = 0.83–0.81, F = 61.22–67.96, internal validation parameters such as Q2LOO = 0.79–0.77, Q2LMO = 0.78–0.76, CCCcv = 0.89–0.88, and external validation parameters such as, R2ext = 0.82 and CCCex = 0.90. In terms of mechanistic interpretation and statistical analysis, both QSAR models are well-balanced. Furthermore, utilizing the pharmacophoric features revealed by QSAR modelling, molecular docking experiments corroborated with the most active compound’s binding to the LSD1 receptor. The docking results are then refined using Molecular dynamic simulation and MMGBSA analysis. As a consequence, the findings of the study can be used to produce LSD1/KDM1A inhibitors as anticancer leads. 相似文献
35.
Najeeb Ur Rehman Mohd Nazam Ansari Abdul Samad Wasim Ahmad 《Molecules (Basel, Switzerland)》2022,27(4)
Fenchone is a bicyclic monoterpene found in a variety of aromatic plants, including Foeniculum vulgare and Peumus boldus, and is used in the management of airways disorders. This study aimed to explore the bronchodilator effect of fenchone using guinea pig tracheal muscles as an ex vivo model and in silico studies. A concentration-mediated tracheal relaxant effect of fenchone was evaluated using isolated guinea pig trachea mounted in an organ bath provided with physiological conditions. Sustained contractions were achieved using low K+ (25 mM), high K+ (80 mM), and carbamylcholine (CCh; 1 µM), and fenchone inhibitory concentration–response curves (CRCs) were obtained against these contractions. Fenchone selectively inhibited with higher potency contractions evoked by low K+ compared to high K+ with resultant EC50 values of 0.62 mg/mL (0.58–0.72; n = 5) and 6.44 mg/mL (5.86–7.32; n = 5), respectively. Verapamil (VRP) inhibited both low and high K+ contractions at similar concentrations. Pre-incubation of the tracheal tissues with K+ channel blockers such as glibenclamide (Gb), 4-aminopyridine (4-AP), and tetraethylammonium (TEA) significantly shifted the inhibitory CRCs of fenchone to the right towards higher doses. Fenchone also inhibited CCh-mediated contractions at comparable potency to its effect against high K+ [6.28 mg/mL (5.88–6.42, n = 4); CCh] and [6.44 mg/mL (5.86–7.32; n = 5); high K+]. A similar pattern was obtained with papaverine (PPV), a phosphodiesterase (PDE), and Ca2+ inhibitor which inhibited both CCh and high K+ at similar concentrations [10.46 µM (9.82–11.22, n = 4); CCh] and [10.28 µM (9.18–11.36; n = 5); high K+]. However, verapamil, a standard Ca2+ channel blocker, showed selectively higher potency against high K+ compared to CCh-mediated contractions with respective EC50 values of 0.84 mg/mL (0.82–0.96; n = 5) 14.46 mg/mL (12.24–16.38, n = 4). The PDE-inhibitory action of fenchone was further confirmed when its pre-incubation at 3 and 5 mg/mL potentiated and shifted the isoprenaline inhibitory CRCs towards the left, similar to papaverine, whereas the Ca2+ inhibitory-like action of fenchone pretreated tracheal tissues were authenticated by the rightward shift of Ca2+ CRCs with suppression of maximum response, similar to verapamil, a standard Ca2+ channel blocker. Fenchone showed a spasmolytic effect in isolated trachea mediated predominantly by K+ channel activation followed by dual inhibition of PDE and Ca2+ channels. Further in silico molecular docking studies provided the insight for binding of fenchone with Ca2+ channel (−5.3 kcal/mol) and K+ channel (−5.7), which also endorsed the idea of dual inhibition. 相似文献
36.
Ali Akbar Ashkarran Azam Iraji?zad Seyed Mohammad Mahdavi Mohammad Mahdi Ahadian 《Applied Physics A: Materials Science & Processing》2010,100(4):1097-1102
ZnO nanostructures were synthesized through arc discharge of zinc electrodes in deionized (DI) water. X-ray diffraction (XRD)
analysis of the prepared nanostructures indicates formation of crystalline ZnO of hexagonal lattice structures. Transmission
electron microscopy (TEM) images illustrate rod-like as well as semi spherical ZnO nanoparticles with 15–20 nm diameter range,
which were formed during the discharge process with 5 A arc current. The average particle size was found to increase with
the increasing arc current. X-ray photoelectron spectroscopy (XPS) analysis confirms formation of ZnO at the surface of the
nanoparticles. Surface area of the sample prepared at 5 A arc current, measured by BET analysis, was 34 m2/g. Photodegradation of Rhodamine B (Rh. B) shows that the prepared samples at lower currents have a higher photocatalytic
activity due to larger surface area and smaller particle size. 相似文献
37.
We have achieved the synthesis of C15-C27 fragment of venturicidine X using desymmetrization protocol, substrate-controlled Grignard reaction, Barton-McCombie reaction, Sharpless epoxidation, and TBSOTf-mediated rearrangement to produce the aldol product through a non-aldol route as the key step following 23 longest linear sequences with 6.4% overall yield starting from a known intermediate 11. 相似文献
38.
Ricardo Elgul Samad Lilia Coronato Courrol Ademar Benévolo Lugão Anderson Zanardi de Freitas Nilson Dias Vieira 《Radiation Physics and Chemistry》2010,79(3):355-357
We report here the creation of color centers in commercial, transparent PMMA samples by ultrashort pulses from a Ti:Sapphire laser emitting at 800 nm, with spatial control. Although the 800 nm photon energy is not sufficient to ionize the polymer, the centers are created following a multiphotonic absorption that causes the ionization. We propose that the free electrons quivering motion on the pulse electric field displaces atoms from its equilibrium positions, creating free radicals and double bonds that coalesce into color centers. The absorption and emission spectra of the centers were measured, but a dose-like curve could not be built due to the presence of damages created along with the centers that scatter the excitation and emission lights due to the commercial sample's poor optical quality. 相似文献
39.
A novel, one-pot reductive mono-alkylation method of amines (primary and secondary), 1,2-phenylenediamine, O-trimethylsilylhydroxylamine, and N,N-dimethylhydrazine was developed using LiClO4 (5 mol %) as a source for in situ generation of imine, iminium ion, oxime, and hydrazone, and zirconium borohydride-piperazine complex as reducing agent. This condition is especially useful for situations in which it is not practical to use the amine in excess (as is typically the case under acid-catalyzed conditions) or for acid-sensitive compounds. 相似文献
40.
As one of the most recently developed membrane separation processes, nanofiltration (NF) has found a number of industrial applications. Ceramic NF membranes are also regarded as the appropriate choice in many applications, due to their higher chemical and physical stability. In this study, the rejection of the chloride ion is investigated using bi-layered γ-Al2O3-TiO2 NF membranes based on α-alumina supports. Compression is used in preparation of the supports and sol-gel dip-coating for the top-layer formation. SEM micrographs, XRD, and nitrogen adsorption/desorption isotherms are used for membrane characterisation. The results show that the calcination temperature (600°C) results in different crystal structures including the brookite phase of TiO2, the γ phase of Al2O3, and a combined phase of aluminium-titanium oxides. The average pore size of the membrane was identified as 1.6 nm using an adsorption/desorption isotherm. The rejection was also studied for the chloride ion, using a cross-flow filtration module. Filtration tests were carried out under different pressures, pH values, and salt concentrations; these showed a smoother behaviour particularly around the isoelectric points (IEPs) due to the dual-layer structure, with the best rejection at pH of approximately 5. 相似文献