- Effective liquid phase hydrodechlorination of diclofenac catalysed by Pd/CeO2
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Palladium catalysts supported on Al2O3, activated carbon (AC), SiO2 and CeO2 were prepared using the impregnation and deposition-precipitation methods. The liquid phase catalytic hydrodechlorination of diclofenac on the catalysts was investigated, and the toxicity of the original and treated diclofenac solutions was evaluated using Daphnia magna. Characterization results indicated that the Pd catalyst supported on CeO2 had a higher Pd dispersion than those supported on Al2O3, AC and SiO2. The binding energy of Pd 3d5/2 in Pd/CeO2 was higher than Pd/Al2O3 with a similar Pd loading amount. Additionally, for Pd/CeO2 prepared by the deposition-precipitation method the binding energy of Pd 3d5/2 slightly decreased with the Pd loading amount. As for catalytic diclofenac reduction, Pd/SiO2 exhibited a nearly negligible catalytic activity, whereas diclofenac concentration decreased by 100, 86, and 29% within 50 min of reaction on Pd/CeO2, Pd/Al2O3, and Pd/AC, respectively, indicative of a catalytic activity order of Pd/CeO2 > Pd/Al2O3 > Pd/AC > Pd/SiO2. The hydrodechlorination of diclofenac on Pd/CeO2 could be well described using the Langmuir-Hinshelwood model. Diclofenac hydrodechlorination processed via a combined stepwise and concerted pathway, and increasing Pd loading amount in Pd/CeO2 favoured the concerted pathway. In comparison with original diclofenac, catalytic hydrodechlorination of diclofenac led to markedly decreased toxicity to Daphnia magna.
- Wu, Ke,Qian, Xiaojun,Chen, Liangyan,Xu, Zhaoyi,Zheng, Shourong,Zhu, Dongqiang
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- Degradation kinetics and mechanism of diclofenac by UV/peracetic acid
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In this work, the degradation kinetics and mechanism of diclofenac (DCF) by UV/peracetic acid (PAA) was investigated. The effects of pH, PAA dose and common water components such as inorganic ions and dissolved organic matter (DOM) on DCF degradation by UV/PAA were also evaluated. It was observed that the addition of PAA promoted the photodegradation of DCF due to the generation of reactive radicals in the photolysis of PAA, which was also confirmed by the radical scavenging experiment. The best degradation efficiency of DCF was obtained at pH 8.5. The removal of DCF was enhanced gradually with increasing PAA dose. Since NO3- is a photosensitive substance which can generate HO under UV irradiation, its existence promoted the degradation of DCF. The presence of CO32- could slightly improve DCF degradation, which might be due to the role of generated carbonate radicals. Cl-, SO42- and Fe3+ had little effect on DCF removal, while Cu2+ could enhance DCF degradation because of its catalytic ability for PAA decomposition. An inhibition effect on DCF removal was observed in the presence of DOM, and it was more obvious in higher concentration of DOM. The elimination of total organic carbon (TOC) was low. According to the twelve reaction products detected in the UV/PAA system, the probable transformation mechanism of DCF was proposed exhibiting eight reaction pathways, i.e., hydroxylation, decarboxylation, formylation, dehydrogenation, dechlorination-hydrogenation, dechlorination-cyclization, dechlorination-hydroxylation and amidation. This study indicates that UV/PAA is a promising method for DCF removal from contaminated water.
- Fu, Yongsheng,Liu, Yiqing,Zhang, Li
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p. 9907 - 9916
(2020/03/23)
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- Pd/C-Et3N-mediated catalytic hydrodechlorination of aromatic chlorides under mild conditions
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A mild and efficient one-pot procedure for the hydrodechlorination of aromatic chlorides using a Pd/C-Et3N system was developed. A variety of aromatic chlorides could be dechlorinated at room temperature and under ambient hydrogen pressure. Et3N activates the catalysis and is likely to work as a single electron donor in this system.
- Monguchi, Yasunari,Kume, Akira,Hattori, Kazuyuki,Maegawa, Tomohiro,Sajiki, Hironao
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p. 7926 - 7933
(2007/10/03)
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- Design, synthesis and?in?vivo anticonvulsant screening in?mice of?Novel phenylacetamides
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A set of seven novel N-substituted 2-anilinophenylacetamides were designed by pharmacophore generation and using flexible alignment module of MOE software. The novel molecules were synthesized and screened for anticonvulsant activity in Swiss albino mice by MES and ScPTZ induced seizure tests. Test compounds were found to be potent in MES test. Compounds 12 and 14 were found to be more potent with ED50 values 24.0 and 8.0?mg kg-1, respectively, and their activity was comparable to standard drugs (Phenytoin, Carbamazepine). Test compounds did not show significant activity in ScPTZ test. Compounds 12 and 14 also exhibited higher protective indices (20.3 and 87.5, respectively) when assessed for neurotoxicity by rotarod test as compared to the standards.
- Shindikar,Khan,Viswanathan
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p. 786 - 792
(2007/10/03)
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- A new synthesis of oxcarbazepine using a Friedel-Crafts cyclization strategy
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A novel, simple, and straightforward process for the large-scale synthesis of oxcarbazepine, the active ingredient of Trileptal, a medicine for the treatment of epilepsy, has been developed. Starting from readily available 1,3-dihydro-1-phenyl-2H-indol-2-one, a Friedel-Crafts cyclization strategy provides a direct route to the tricyclic framework of the target molecule. Crucial to the success of the strategy was the choice of the proper nitrogen-protecting group.
- Kaufmann, Daniel,Fünfschilling, Peter C.,Beutler, Ulrich,Hoehn, Pascale,Lohse, Olivier,Zaugg, Werner
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p. 5275 - 5278
(2007/10/03)
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- A convenient preparation of N-alkyl and N-arylamines by smiles rearrangement - Synthesis of analogues of diclofenac
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Smiles rearrangement of substituted aryloxyacetamides in which oxygen and nitrogen are separated by COCH2 group has been successful even when the aryloxy ring carries weak or no electron withdrawing group. Earlier reports of such reactions involved either strong electron withdrawing groups or a special catalyst. The diphenylamines thus obtained gave analogues of diclofenac in only one case.
- Wadia,Patil
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p. 2725 - 2736
(2007/10/03)
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- Albumin-binding compounds that prevent nonenzymatic glycation and that may be used for treatment of glycation-related pathologies
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The present invention is directed to compositions that inhibit the nonenzymatic glycation of albumin,, as well as methods of using compounds that inhibit albumin glycation for the treatment of glycation-related pathologies.
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- Synthesis and quantitative structure-activity relationships of diclofenac analogues
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The synthesis of a series of 2-anilinophenylacetic acid, close analogues of diclofenac, is described. These compounds were tested in two models used for evaluating the activity of nonsteroidal antiinflammatory drugs (NSAID's), inhibition of cyclooxygenase enzyme activity in vitro, and adjuvant-induced arthritis (AdA) in rats. Statistically significant correlations were found between the inhibitory activities of the compounds in these two models, indicating that cyclooxygenase inhibition seems to be the underlying mechanism for the antiinflammatory activity of these compounds. Quantitative structure-activity relationship (QSAR) analysis revealed that the crucial parameters for activity in both models were the lipophilicity and the angle of twist between the two phenyl rings. Optimal activities were associated with halogen or alkyl substituents in both ortho positions of the anilino ring. Compounds with OH groups in addition to two ortho substituents or compounds with only one or no ortho substituents were less active.
- Moser,Sallmann,Wiesenberg
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p. 2358 - 2368
(2007/10/02)
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