- One-pot synthesis of 1,3,4-thiadiazoles using Vilsmeier reagent as a versatile cyclodehydration agent
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A simple and efficient synthetic method for the one-pot synthesis of 1,3,4-thiadiazoles utilizing Vilsmeier reagent was developed. In this method carboxylic acids and hydrazine were converted to 1,3,4-thiadiazoles in the presence of Vilsmeier reagent and Lawesson's reagent. The influence of the thionation reagent, solvent, temperature and time, in this reaction was discussed. The developed methodology for 1,3,4-thiadiazole synthesis has the advantage of simplicity, ambient reaction conditions, easy purification and good to excellent yield of products.
- Zarei, Maaroof
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p. 1867 - 1872
(2017/03/11)
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- Design, synthesis and biological evaluation of some oxadiazole derivatives as novel amide-based inhibitors of soluble epoxide hydrolase
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Soluble epoxide hydrolase (sEH) enzyme plays an important role in the metabolism of endogenous chemical mediators which are involved in the regulation of blood pressure and inflammation. Although the most reported potent sEH inhibitors are urea derivatives, these compounds have limited pharmacokinetic profile. In order to improve physicochemical properties, besides having favorable potency, amide non-urea derivatives with oxadiazole ring as a novel secondary pharmacophore against sEH enzyme were developed. Most of the novel compounds with appropriate physical properties, had comparable in vitro sEH inhibitory activity to 12-(3-Adamantan-1-yl-ureido)-dodecanoic acid (AUDA), a potent urea-based sEH inhibitor. The IC50value of the most potent compound (15c) was 0.43 nM.
- Rezaee, Elham,Hedayati, Mahdi,Rad, Laleh Hoghooghi,Kiani, Azin,Shahhosseini, Soraya,Faizi, Mehrdad,Tabatabai, Sayyed Abbas
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p. 721 - 730
(2014/07/07)
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- Synthesis and methemoglobinemia-inducing properties of benzocaine isosteres designed as humane rodenticides
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A number of isosteres (oxadiazoles, thiadiazoles, tetrazoles and diazines) of benzocaine were prepared and evaluated for their capacity to induce methemoglobinemia - with a view to their possible application as humane pest control agents. It was found that an optimal lipophilicity for the formation of methemoglobin (metHb) in vitro existed within each series, with 1,2,4-oxadiazole 3 (metHb% = 61.0 ± 3.6) and 1,3,4-oxadiazole 10 (metHb% = 52.4 ± 0.9) demonstrating the greatest activity. Of the 5 candidates (compounds 3, 10, 11, 13 and 23) evaluated in vivo, failure to induce a lethal end-point at doses of 120 mg/kg was observed in all cases. Inadequate metabolic stability, particularly towards hepatic enzymes such as the CYPs, was postulated as one reason for their failure.
- Conole, Daniel,Beck, Thorsten M.,Jay-Smith, Morgan,Tingle, Malcolm D.,Eason, Charles T.,Brimble, Margaret A.,Rennison, David
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p. 2220 - 2235
(2014/04/17)
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- 17O NMR studies of substituted 1,3,4-oxadiazoles
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Three series of substituted 1,3,4-oxadiazoles were studied by 17O NMR spectroscopy. Chemical shifts values were correlated with empirical Hammett parameters as well as calculated bond lengths and chemical shielding values.
- Gierczyk, Blazej,Zalas, MacIej,Kazmierczak, Marcin,Grajewski, Jakub,Pankiewicz, Radoslaw,Wyrzykiewicz, Bozena
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p. 648 - 654
(2012/01/06)
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- Near-infrared-absorbing organic electrochromic materials
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The invention provides generally a new type of organic electrochromic Near Infrared (NIR)-active materials capable of absorbing and attenuating the light in the NIR region around 1550 nm and forming thin films on electrodes for variable optical attenuator
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Page/Page column 7
(2008/12/07)
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- Chemistry of 2-ylidenefuran-3(2H)-ones: XIX. Reaction of 5-aryl-2(oxoylidene)furan-3(2H)-ones with carboxylic acid hydrazides
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2-[2-(4-Chlorophenyl)-2-oxoethylidene]-5-phenylfuran-3(2H)-one and methyl (5-aryl-3-oxo-2,3-dihydrofuran-2-ylidene)acetates react with carboxylic acid hydrazides to give the corresponding 3-substituted 2-acyl-6-aryl-3-hydroxy-2,3- dihydropyridazin-4(1H)-ones. Specificities of the product structure are discussed.
- Koz'minykh,Goncharov,Koz'minykh
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p. 864 - 867
(2008/02/10)
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- A mild and efficient one pot synthesis of 1,3,4-oxadiazoles from carboxylic acids and acyl hydrazides
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A convenient one pot method for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles from acids and acyl hydrazides is reported. Acid activation with CDI, followed by coupling with the desired acylhydrazide and dehydration in the same pot with Ph3P and CBr4 affords the corresponding 1,3,4-oxadiazoles in good yield. The scope of the acid and acylhydrazide components is presented.
- Rajapakse, Hemaka A.,Zhu, Hong,Young, Mary Beth,Mott, Bryan T.
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p. 4827 - 4830
(2007/10/03)
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- An expeditious and convenient one pot synthesis of 2,5-disubstituted-1,3,4-oxadiazoles
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A convenient, one pot procedure is reported for the synthesis of a variety of 2,5-disubstituted-1,3,4-oxadiazoles by condensing monoarylhydrazides with acid chlorides in HMPA solvent under the microwave heating. The yields are good to excellent, the process is rapid and does not need any added acid catalyst or dehydrating reagent.
- Mashraqui, Sabir H.,Ghadigaonkar, Shailesh G.,Kenny, Rajesh S.
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p. 2541 - 2545
(2007/10/03)
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- Substitution Reactions of Phenylated Aza-heterocycles. Part 1. Nitration of 2,5-Diphenyl-1,3,4-oxadiazole: a Product Study using High Performance Liquid Chromatography
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Contrary to a previous literature report, nitration of 2,5-diphenyl-1,3,4-oxadiazole (1) under various conditions gives a mixture of all six possible 2,5-bisnitrophenyl derivatives, which may be analysed quantitatively using high performance liquid chromatography.Nitration using nitric acid alone gives mainly the three isomers with p-nitrophenyl groups, i.e. (7), (9), and (10), whereas mixed acids and nitronium tetrafluoroborate give mainly meta-nitration products, i.e. (6), (8), and (9).Nitration of the three 2-(nitrophenyl)-5-phenyl-1,3,4-oxadiazoles also shows considerable variation of product ratio according to the conditions.
- Blackhall, Alexander,Brydon, Donald L.,Saga, Anthony J. G.,Smith, David M.
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p. 773 - 777
(2007/10/02)
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