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61.
Rahman Hosseinzadeh Mahmood Tajbakhsh Maryam Mohadjerani Zahra Lasemi 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):57-60
Abstract Ethylenebis(N-methylimidazolium) ditribromide, a stable crystalline solid, is easily prepared by reaction of the corresponding dibromide
salt with bromine in n-hexane. 1,3-Diketones and β-ketoesters can be brominated chemoselectively to the corresponding α-monobrominated products
by using this reagent at 0–5 °C. Under the same reaction conditions, diethyl malonate, ethyl cyanoacetate, and malonitrile
were monobrominated at moderate yield.
Graphical abstract
相似文献
62.
Zandi K Ramedani E Mohammadi K Tajbakhsh S Deilami I Rastian Z Fouladvand M Yousefi F Farshadpour F 《Natural product communications》2010,5(12):1935-1938
Antiviral drug resistance is one of the most common problems in medicine, and, therefore, finding new antiviral agents, especially from natural resources, seems to be necessary. This study was designed to assay the antiviral activity of curcumin and its new derivatives like gallium-curcumin and Cu-curcumin on replication of HSV-1 in cell culture. The research was performed as an in vitro study in which the antiviral activity of different concentrations of three substances including curcumin, Gallium-curcumin and Cu-curcumin were tested on HSV-1. The cytotoxicity of the tested compounds was also evaluated on the Vero cell line. The CC50 values for curcumin, gallium-curcumin and Cu-curcumin were 484.2 microg/mL, 255.8 microg/mL and 326.6 microg/mL, respectively, and the respective IC50 values 33.0 microg/mL, 13.9 microg/mL and 23.1 microg/mL. The calculated SI values were 14.6, 18.4 and 14.1, respectively. The results showed that curcumin and its new derivatives have remarkable antiviral effects on HSV-1 in cell culture. 相似文献
63.
Courty S Tajbakhsh AR Terentjev EM 《The European physical journal. E, Soft matter》2003,12(4):617-625
Cholesteric elastomers possess a macroscopic phase chirality as the director
rotates in a helical fashion along an optical axis z and can be described by a chiral order parameter
. This parameter can be tuned by changing the helix pitch p and the elastic properties of the network at formation. The cholesterics also possess a local nematic order, changing with temperature or during solvent swelling. In this paper, by measuring the power of optical rotation
, we discover how these two parameters vary as functions of temperature or solvent adsorbed by the network. The main result is a finding of pronounced stereo-selectivity of cholesteric elastomers, demonstrating itself in the retention of the correct chirality component of a racemic solvent. It has been possible to quantify the amount of such stereo-separation, and the basic dynamics of the effect.Received: 18 August 2003, Published online: 5 February 2004PACS:
33.55.Ad Optical activity, optical rotation; circular dichroism - 61.30.Vx Polymer liquid crystals - 87.80.Pa Morphometry and stereology 相似文献
64.
Molecular chirality, and the chiral symmetry breaking of resulting macroscopic phases, can be topologically imprinted and manipulated by cross-linking and swelling of polymer networks. We present a new experimental approach to stereo-specific separation of chiral isomers by using a cholesteric elastomer in which a helical director distribution has been topologically imprinted by cross-linking. This makes the material unusual in that is has a strong phase chirality, but no molecular chirality at all; we study the nature and parameters controlling the twist-untwist transition. Adding a racemic mixture to the imprinted network results in selective swelling by only the component of "correct" handedness. We investigate the capacity of demixing in a racemic environment, which depends on network parameters and the underlying nematic order. 相似文献
65.
Novel One‐Pot Three‐Component Reaction for the Synthesis of Functionalized Spiroquinazolinones 下载免费PDF全文
Mahdieh Tajbakhsh Sorour Ramezanpour Saeed Balalaie Hamid Reza Bijanzadeh 《Journal of heterocyclic chemistry》2015,52(5):1559-1564
A wide variety of spiroquinazolinone derivatives have been synthesized via a one‐pot three‐component reaction of isatoic anhydride, cyclic ketones, and hydrazides in the presence of catalytic amount (20 mol%) of H3PO3 in ethanol. Mild reaction conditions, high atom economy, operational simplicity, and good to high yields are the key advantages of the present protocol. 相似文献
66.
A novel five-component strategy involving commercially available diketene, primary amines, malononitrile and various benzaldehydes for the synthesis of densely functionalized 1,4-dihydropyridines in good yields was achieved. The reaction pathway involves a sequential ring-opening of diketene/enamine formation/Knoevenagel-condensation/Michael addition and 6-exo-tet cyclization, resulting in multiple bond-formation events including two C–C and three C–N bonds ultimately leading to the formation of the respective 1,4-dihydropyridines. 相似文献
67.
Mohammad A. Khalilzadeh Abolfazl Hosseini Mahmoud Tajbakhsh 《Journal of heterocyclic chemistry》2007,44(3):535-538
Effects of microwave irradiation on the solid‐phase synthesis of tacrine and its derivatives have been evaluated. Preparation of tacrine analogues under conventional conditions suffers from poor synthetic efficiency and usually gives low yield. Reaction of substituted anthranilonitrile with cyclohexanone under microwave irradiation gave a good to excellent yield of the corresponding substituted 9‐amino‐1,2,3,4‐tetrahydroacridines. 相似文献
68.
Rahman Hosseinzadeh Mohammad Mavvaji Mahmood Tajbakhsh Zahra Lasemi 《Journal of the Iranian Chemical Society》2018,15(4):893-904
In this study, N-hydroxyphthalimide (NHPI) was successfully attached on functionalized SiO2-coated Fe3O4 nanoparticles through amid bond. The sustained nanomagnetite-immobilized NHPI as a new magnetically recoverable catalyst was characterized by FT-IR, XRD, TGA, VSM, TEM and SEM techniques. The prepared catalyst exhibited high selectivity for oxidation of various benzyl alcohols and hydrocarbons in the presence of hydrogen peroxide as oxidant. The catalyst can be readily separated from the reaction mixture using an external magnet and reused several times without significant loss of its catalytic activity. 相似文献
69.
Gholam Babaei Chalmardi Mahmood Tajbakhsh Nahid Hasani Ahmadreza Bekhradnia 《Tetrahedron》2018,74(18):2251-2260
A novel Schiff base fluorescent sensor N,N′-bis(salicylidene)-2,6-bis(4-aminophenyl)-4-phenylpyridine (P3) was synthesized through condensation of 2,6-bis(4-aminophenyl)-4-phenylpyridine and 2-hydroxybenzaldehyde. The obtained results from fluorescence analysis revealed that by excess of Cr3+ to P3, a remarkable increase was observed in the fluorescent intensity of the Schiff base at 663?nm with the ratio of CH3CN/H2O (95/5%), even though the other cations would likely have no impact on the fluorescence intensity. The cause of this trend might be ascribed to the formation of a 1:1 stoichiometric P3-Cr3+ complex, confirmed by Job's plot, which is resulted in preventing the photo-induced electron transfer (PET) process. From fluorescence titration, the association constant Ka was gained 2.28?×?105?M?1 and the limit of detection (LOD) was determined to be 1.3?×?10?7?M. Furthermore, the optimized structure together with the electronic spectra of the proposed complex was determined by DFT and TDDFT calculations. 相似文献
70.
Vahideh Zadsirjan Majid M. Heravi Mahmoud Tajbakhsh Hossein A. Oskooie Morteza Shiri Tayebeh Hosseinnejad 《Research on Chemical Intermediates》2016,42(7):6407-6422
Hydroarylation of cinnamic acid with different substituted phenols, in the presence of acidic ionic liquid, N-methyl-2-pyrrolidonum hydrosulfate ([H-NMP]HSO4) gave the corresponding dihydrocoumarins in high yields and excellent selectivity. Among these substituted phenols, while methyl phenol afforded the corresponding dihydrocoumarin, nitrophenol under the same reaction conditions diverted the course of reaction, affording 3-(4-nitrophenyl)-3-phenylpropanoic acids. We investigated this behavior from the energetic and electronic points of view, using quantum chemistry computational methods. In this respect, the electronic energy change values for the conversion reaction of substituted phenyl cinnamate esters to dihydrocoumarin compounds have been obtained via density functional theory calculations. We demonstrated that the conversion reaction in the presence of CH3 substituent is more favorable energetically than NO2 substituent. Moreover, we have concentrated on topological analysis of electron density on some key bond and ring critical points and their associated bond paths to assess the conversion of substituted phenyl cinnamate esters to dihydrocoumarins. Our calculated results showed that para-methyl phenyl cinnamate has more of electronic tendency to undergo the intramolecular cyclization step and, consequently, generate the corresponding dihydrocoumarin. 相似文献