- Evaluation of malonic acid diamide analogues as radical scavenging agents
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The malonic acid diamide analogues such as N,N′-dimethyl-N,N′-dioctyl-malonamide (DMDOMA), N,N′-dimethyl-N,N′-dioctyl-2,(2′-hexyloxyethyl) malonamide (DMDOHEMA), N,N′-dimethyl-N,N′-dicyclohexyl-malonamide (DMDCMA) and N,N,N′,N′-tetraisopropyl malonamide (TiPMA) were synthesized by an ester amine coupling method. These synthesized diamides were evaluated for the scavenging activity of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide anion scavenging and ferric reducing antioxidant power (FRAP), by biochemical methods. Antioxidant properties exhibited by these diamides were compared with standard antioxidants like gallic acid and ascorbic acid. The pulse radiolysis technique was employed to generate 2-2′-azinobis 3-ethylbenzothioline-6-sulfonic acid (ABTS+), hydroxyl radicals (OH), and carbonate (CO3-) radicals for evaluating the scavenging activity of the diamides. DMDCMA, TiPMA, and DMDOMA were found to show better antioxidant potential as compared to DMDOHEMA due to their more hydrophilic nature. The pulse radiolysis technique was found to be advantageous for investigating the interaction of the diamide class of compounds with radicals generated under high energy radiation.
- Patil, Ajay B.,Ghosh, Sougata,Phadatare, Suvarna D.,Pathak, Priyanath,Sharma, Geeta K.,Chopade, Balu A.,Shinde, Vaishali S.
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- Chitosan grafted with a heteropolyanion-based ionic liquid as an effective and reusable catalyst for acetalization
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Chitosan immobilized with an acidic ionic liquid (CS-VImPS-PW) was fabricated via a radical addition reaction of N-vinylimidazoliumpropane sulfonate and chitosan, followed by acidification with a heteropolyacid. It was characterized by a Fourier transform infrared spectrometer, solid-state 13C nuclear magnetic resonance spectrometer, thermogravimetric analyzer, elemental analyzer, and Hammett indicator. Some acetalization reactions were investigated to evaluate the catalytic activity of CS-VImPS-PW. The results show that CS-VImPS-PW is highly active for the acetalization reactions in high acetal yields ranging from 83.2 to 96.2% and can be reused 8 times without noticeable loss of activity.
- Zhang, Wei-Hong,Liu, Shan-Shan,Liu, Ping,Xu, Jie,Xue, Bing,Wei, Xian-Yong,Li, Yong-Xin
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p. 41404 - 41409
(2016/05/19)
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- β-Carotene: A green, inexpensive, and convenient solvatochromic probe for the determination of solvent polarizability
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Solvent polarizability has been previously determined by using the solvatochromic probe 3,20-di-tert-butyl-2,2,21,21-tetramethyl-3,5,7,9,11,13,15, 17,19-docosanonaene whose synthesis involves 15 steps. We show here that the natural dye β-carotene, 1,1′-(3,7,12,16-tetramethyl-1,3,5,7,9,11,13, 15,17-octadecanonaene-1,18-diyl)bis[2,6,6-trimethylcyclohexene], can be conveniently employed for the accurate determination of the same solvent property. This conclusion is based on both theoretical calculations and experimental data. The former includes free energies of solvation, and the wavenumber of the longest wavelength (i.e., the solvatochromic) transition. Both quantities for β-carotene correlate linearly with the corresponding values of the docosanonaene, with slopes and correlation coefficients of practically unity. The plot of experimentally calculated solvent polarizability of β-carotene versus that of the docosanonaene was found to be linear for 68 solvents. Previously unknown solvent polarizability values are reported for eight ROCH2CH2OH (R = C1 to C10) and four 1-allyl-3-R-imidazolium chloride ionic liquids (R = C6 to C10). The dependence of solvent polarizability on the number of carbon atoms in the hydrocarbon chains of several classes of solvents is calculated, it shows the importance of van der Waals interactions in ionic liquids.
- Loffredo, Carina,Pires, Paulo Augusto R.,Imran, Muhammad,El Seoud, Omar A.
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p. 16 - 24,9
(2020/07/31)
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- A Synthesis of acetamidines
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The condensation of primary amine with N,N-dimethylacetamide dimethyl acetal yields amixture of acetamidine and imidate ester. The product distribution in this reaction depends on the temperature, solvent, and structure of the primary amine. It is possible to suppress the formation of imidate ester by performing the reaction in the presence of excess dimethyl amine, yielding acetamidine as the exclusive product. For acetamidines that cannot be purified either by crystallization or distillation, this new method is necessary for the generation of pure acetamidines in good yields.
- Harjani, Jitendra R.,Liang, Chen,Jessop, Philip G.
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experimental part
p. 1683 - 1691
(2011/05/12)
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- Synthesis and antiproliferative activity of alkylphosphocholines
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Alkylphosphocholines (APC) with one or more methylene groups in the alkyl chain replaced by oxygen atoms or carbonyl groups, or both have been assembled modularly using ω-diols as central building blocks. Out of 25 new compounds of this kind, 11 were evaluated for their antiproliferative activity on four cell lines and compared with miltefosine to evaluate their hemolytic activity (HA) and cytotoxicity on non-tumoral cells (MT2), used as markers of adverse effects. Compound 13 was more active on cancer cell lines than on non-tumoral cells and the data were similar for MTT and thymidine incorporation assays. It had less HA than miltefosine. Compound 13 could therefore be a candidate for the preparation of compounds with higher cytotoxicity on cancer cells and lower general toxicity.
- Agresta, Mandy,D'Arrigo, Paola,Fasoli, Ezio,Losi, Daniele,Pedrocchi-Fantoni, Giuseppe,Riva, Simona,Servi, Stefano,Tessaro, Davide
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p. 201 - 210
(2007/10/03)
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- On the correlation between activity coefficients and association parameters for 1-butanol and 1-hexanol
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In a study of the phase equilibria of binary mixtures of 1-butanol and 1-hexanol with hexane, a correlation was revealed between the activity coefficients for 1-butanol and 1-hexanol measured in the temperature range 25-27°C. The parameters of their association were determined in a study of the kinetics of irreversible oxyethylation at 100-180°C both in the presence and absence of a solvent (dodecane). A conclusion was drawn on the correlation between the kinetics of this irreversible reaction and the thermodynamic properties of the reactive mixtures studied.
- Stul',Chesnokov
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p. 576 - 578
(2007/10/03)
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