排序方式: 共有98条查询结果,搜索用时 24 毫秒
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Mohammad Bakherad Rahele Doosti Ali Keivanloo Mostafa Gholizadeh Khosrow Jadidi 《Journal of the Iranian Chemical Society》2017,14(12):2591-2597
The catalyst-free multi-component reactions of aldehydes, malononitrile, and sodium azide at a relatively low temperature in magnetized water provided 5-substituted 1H-tetrazoles in high-to-excellent yields. This method offers the advantages of short reaction times, low costs, quantitative reaction yields, simple work-up, green, and no need for any organic solvent. 相似文献
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Mohammad Javad Taghizadeh Hamid ArvinnezhadSaadi Samadi Khosrow Jadidi Abdollah JavidanBehrouz Notash 《Tetrahedron letters》2012,53(38):5148-5150
An efficient, one-pot, three-component procedure for the synthesis of a small library of new chiral spirooxindolopyrrolizidines with high regio-, diastereo-, and enantioselectivity, from the 1,3-dipolar cycloaddition of azomethine ylides and optically active cinnamoyl oxazolidinone is described. The process occurs at room temperature in aqueous ethanol as a green solvent and in the absence of any Lewis acids. The oxazolidinone chiral auxiliary is removed in a non-destructive manner. The reaction mechanism is discussed on the basis of the assignment of the absolute configuration of the cycloadducts, and on theoretical calculations. 相似文献
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Roya Zahedi Faramarz Afshar Taromi Seyed Heidar Mirjahanmardi Mehdi Nekoomanesh Haghighi Roghayeh Jamjah Khosrow Jadidi 《Polymer Science Series B》2016,58(2):143-151
Two new ethers were synthesized using the Williamson reaction from related alcohols and were used as external donors in propylene polymerization in the presence of the industrial diisobutyl phthalate-based MgCl2-supported Ziegler-Natta catalyst. For comparison the propylene polymerization was carried out in the presence of silane and in the absence of external donors. The produced polymers were characterized by differential scanning calorimetry, xylene extraction, melt flow index, scanning electron microscopy and gel permeation chromatography. The isotacticity, molecular weight and molecular weight distribution, melt flow index, crystallinity degree and thermal properties of polypropylenes were influenced by the type of external donors. 相似文献
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Khadijeh Mollanejad Sakineh Asghari Khosrow Jadidi 《Journal of heterocyclic chemistry》2020,57(2):556-564
Diastereoselective synthesis of pyrrolo[1,2-c]imidazoles is reported from three-component reaction of chiral thiohydantoins, aldehydes, and malononitrile in the presence of NEt3. The antioxidant properties of the obtained products were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Among the products, compound 4l possessing NH2 and NH groups and bromine atom at 4-position of the aromatic ring displayed the highest antioxidant activity (90%). Also, their antibacterial activities were explored against gram-positive and gram-negative bacteria using disc diffusion method. Among the synthesized compounds, 4a with chlorine atom at para position of the aromatic ring, and methyl group (the smallest alkyl group) at 7-position, displayed the best antibacterial activity against the tested gram-positive bacteria. 相似文献
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Hamid Arvinnezhad Fatemeh Ghorbani Hormoz Khosravi Khosrow Jadidi Behrouz Notash Soheila Naderi 《Journal of heterocyclic chemistry》2020,57(8):3222-3229
Using both classical reflux and microwave-mediated conditions, a series of new spiroindoloindolizidines was synthesized by multicomponent 1,3-dipolar cycloaddition of azomethine ylides in unprecedented exo/endo stereocontrolled. Both conditions easily afforded two identical and separable exo/endo diastereomeric ratios of cycloadducts. However, the ratio of two diastereomeric products obtained from conventional conditions was reversed in all examined cases when the reactions were explored under microwave-mediated conditions. As expected, utilizing the microwave-assisted conditions produced higher yields and reaction rates compared to classical conditions. The structure and exact stereochemistry of synthesized cycloadducts were determined by applying various 2D-NMR spectroscopic techniques and single-crystal X-ray diffraction. Finally, the mechanism of the reaction has been briefly investigated by using density functional theory (DFT) calculations. 相似文献
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Maleknejad Khosrow Nouri Kazem Torkzadeh Leila 《Mediterranean Journal of Mathematics》2016,13(3):1377-1390
This paper is devoted to studying a computational method for solving multi-term differential equations based on new operational matrix of shifted second kind Chebyshev polynomials. The properties of the operational matrix of fractional integration are exploited to reduce the main problem to an algebraic equation. We present an upper bound for the error in our estimation that leads to achieve the convergence rate of O(M −κ). Numerical experiments are reported to demonstrate the applicability and efficiency of the proposed method.
相似文献8.
Mohammad Ali Zolfigol Farhad Shirini Khosrow Zamani Efat Ghofrani Satar Ebrahimi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2177-2182
Silica phosphoric acid was prepared via reaction of silica chloride (I) and phosphoric acid. Thiols can be readily converted to their corresponding thionitrites with a combination of silica phosphoric acid (II), wet SiO 2 , and sodium nitrite in dichloromethane at room temperature. Disulfides result from the homolytic cleavage of the sulfur–nitrogen bond of the unstable thionitrite and subsequent coupling of the resultant thiyl radicals. 相似文献
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A new fused heterocyclic derivatives of pyrrole containing acetonitrile or cyanoacetonitrile moiety at 3-position is described by a one-pot multicomponent reaction. The reaction of dimedone, various aniline, aryl glyoxal with malononitrile/ethyl cyanoacetate/methyl cyanoacetate under mild conditions. The present method does not involve any hazardous organic solvents or catalysts. The significant features of this method are readily available starting materials, good yields, and easy purification. 相似文献
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When a transparent plane-parallel plate is illuminated at a boundary region by a monochromatic parallel beam of light, Fresnel diffraction occurs because of the abrupt change in phase imposed by the finite change in refractive index at the plate boundary. The visibility of the diffraction fringes varies periodically with changes in incident angle. The visibility period depends on the plate thickness and the refractive indices of the plate and the surrounding medium. Plotting the phase change versus incident angle or counting the visibility repetition in an incident-angle interval provides, for a given plate thickness, the refractive index of the plate very accurately. It is shown here that the refractive index of a plate can be determined without knowing the plate thickness. Therefore, the technique can be utilized for measuring plate thickness with high precision. In addition, by installing a plate with known refractive index in a rectangular cell filled with a liquid and following the described procedures, the refractive index of the liquid is obtained. The technique is applied to measure the refractive indices of a glass slide, distilled water, and ethanol. The potential and merits of the technique are also discussed. 相似文献