363 research outputs found
Efficient one-pot, four-component synthesis of N,N-dibenzyl-N-{1-[5-(3-aryl)-1,3,4-oxadiazol-2-yl]cyclobutyl}amine derivatives from the reaction of (isocyanoimino)triphenylphosphorane, dibenzylamine, an aromatic carboxylic acid and cyclobutanone
Four-component reaction of cyclobutanone, dibenzylamine and (Nisocyanimino) triphenylphosphorane in the presence of aromatic carboxylic acids proceed smoothly at room temperature and under neutral conditions to afford N,N-dibenzyl-N-{1-[5-(3-aryl)-1,3,4-oxadiazol-2-yl]cyclobutyl}amine derivatives in high yields
Characterization and Modeling of Failure Initiation in Bainite‐Aided DP Steel
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109564/1/adem201300556.pd
Investigating Content of Statements’ Information Applies to Financial Performance Evaluation of companies (Evidence from Tehran Stock Exchange)
Purpose- This research aims to study the relationship and effect of economic value added (EVA), return on equity (ROE), retained earnings, return on assets (ROA), cash value added (CVA) and free cash flow (FCF) with stock returns. The population of the research consists of 94 companies accepted in Tehran stock exchange (TSE). Design/methodology/approach- The data were analyzed using Eviews software and at two levels of descriptive and inferential of Pearson correlation coefficient tests and multi-variable regression analysis through step by step method. All hypotheses were confirmed except the relationship between ROA and stock return at 95 percent of confidence level.. Findings- The results of regression analysis indicated that the variable of EVA with -0.231 standard coefficient have the most reverse effect on stock return, the residual profit with the coefficient of 0.172 stood at second rank and free cash flows and EVA respectively with standard beta coefficient of 0.129 and 0.114 were graded third and fourth with positive effect on stock return. Originality/value- The variable of ROA through step by step regression didn’t show meaningful effects on stock return. Then we conclude that the content of statements information significantly explain financial companies performance. Keywords: Information content, Tehran Stock Exchange, Financial Performance.
Vinyltriphenylphosphonium salt-mediated preparation of thiophene-containing electron-poor alkenes from acetylenic esters, 2-thienylmethanol and triphenylphosphine
Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and alkyl acetylenecarboxylates (methyl acetylenecarboxylate, ethyl acetylenecarboxylate and ethyl phenylacetylenecarboxylate) by 2-thienylmethanol leads to vinyltriphenylphosphonium salts, which undergo an addition-elimination reaction in CH2Cl2 at room temperature to produce the corresponding O-vinylated alkenes via thiophene-containing phosphorus ylides intermediates in fairly high yields. The structural analysis of all products indicated that the reactions are regio- and stereoselective.KEY WORDS: 2-Thienylmethanol, Acetylenic ester, Vinyltriphenylphosphonium salt, O-Vinylation, Michael additionBull. Chem. Soc. Ethiop. 2011, 25(1), 91-96
The Prophylactic Effects of Zintoma and Ibuprofen on Post-endodontic Pain of Molars with Irreversible Pulpitis: A Randomized Clinical Trial
Introduction: Post endodontic pain is often linked to the inflammatory process as well as additional central mechanisms. The purpose of the present double-blind randomized clinical trial study was to compare the prophylactic effects of a derivative of Zingiber Officinale, Zintoma, and Ibuprofen on post endodontic pain of molars with irreversible pulpitis. Materials and Methods: The post endodontic pain of 72 enrolled patients suffering from irreversible pulpitis was assessed after prophylactic use of 400 mg Ibuprofen, 2 gr Zintoma and placebo. Using the Heft-Parker Visual Analogue Scale, the patients recorded their perceived pain before taking the medicament (baseline), immediately after and also at 4, 8, 12, 24, 48, and 72 h post one-visit endodontic treatment. The statistical analysis was done using Kruskal-Wallis, Mann-Whitney, and Freedman tests (P<0.05). Results: At all times, there was significant difference between the Ibuprofen and Zintoma (P<0.05) and also between the Ibuprofen and placebo (P<0.05). However, there was no significant difference between Zintoma and the placebo in any of time intervals (P>0.05). No side effects were observed. Conclusion: The obtained results of the trial revealed that prophylactic use of 2 gr Zintoma is not an effective pain relieving agent
Systematic Modeling of Drug P-Glycoprotein Interactions via Combined Docking/QM Approach
Introduction: The overexpression of P-gp in cancer tumor cells results in increased efflux of chemotherapeutic compounds. This phenomenon leads to the wide-spectrum resistance of cancer cells to variant drugs or multi drug resistance (MDR). Regarding the important biological role of P-gp with regard to cancer therapy, in silico analysis of binding affinity/mode of diverse anticancer drugs toward P-gp may be an active area of research since it provides more insight into the binding interactions and key amino acid residues that were involved.
Methods and Results: Ligand-flexible docking studies were performed using the molecular docking software, AutoDock 4.2. To elucidate the interactions of selected anticancer drugs, all the related structures were docked into the active site of validated P-gp target (4XWK). Quantum mechanical calculations were applied to intermolecular binding energy analysis in terms of drug-residue binding interactions via functional B3LYP in association with split valence basis set using polarization functions (Def2-SVP).
Mitomycin was found to be the weakest binder with -7.29 kcal/mol energy. Bisantrene was the top-ranked binder (-10.59 kcal/mol) with H-bond and lipophilic interaction patterns. To explain more, Asn838 participated in bidentate H-bonding with nitrogen atom of imidazole ring. Another H-bond interaction was detected in the case of Ser725 within the same ring but different nitrogen atom of the drug molecule. Besides hydrogen bonding, it was revealed that 12 hydrophobic residues interacted with Bisantrene. Within the evaluated drugs, unlike Epothilone E and F, no H-bonds could be detected for Epothilone A, B, C & D. Such observation was pertained to the presence of hydroxymethyl moiety on the thiazole ring of Epothilone E and F which provided well-oriented H-bonds with Ala307. Despite observed interactive residues, lower binding affinity of Epothilone F persuaded us to run QM job in terms of drug-residue binding interactions. It was interestingly concluded that a few residues made repulsive forces with the drug, a result that might explain lower affinity of this molecule toward P-gp.
Conclusions: Collective in silico exploration of a few anticancer drugs provided some insights into the binding mode toward P-gp as an interfering target in chemotherapeutic strategies. On the basis of obtained results, structure binding relationship pattern for studied anticancer drugs were developed
Passerini multicomponent reaction of indane-1,2,3-trione: an efficient route for the one-pot synthesis of sterically congested 2,2-disubstituted indane-1,3-dione derivatives
The Passerini reaction of indane-1,2,3-trione, isocyanides and benzoic acid derivatives proceed at room temperature and sterically congested 2,2-disubstituted indane-1,3-dione derivatives are synthesized in excellent yields. The reaction proceeds smoothly and cleanly under mild conditions and no side reactions are observed
Zeolite-Based Catalysts: A Valuable Approach toward Ester Bond Formation
Zeolite-based catalysts are versatile catalytic systems for a wide range of laboratory studies and industrial scale processes. The chemical composition, ion exchange, and pore size structure attributes of zeolites are responsible for their extensive catalytic applications. Esterification is one of the most important and routinely processes in diverse fields of organic synthesis. It has a long history in both industrial processes and laboratory work due to its versatility. This review intends to give a detailed insight into the significance of zeolite-based catalysts for ester bond formation
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