- Beyond direct Nrf2 activation; reinvestigating 1,2,4-oxadiazole scaffold as a master key unlocking the antioxidant cellular machinery for cancer therapy
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Harnessing the antioxidant cellular machinery has sparked considerable interest as an efficient anticancer strategy. Activating Nrf2, the master switch of the cellular redox system, suppresses ROS, alleviates oxidative stress, and halts cancer progression
- Ayoup, Mohammed Salah,Abu-Serie, Marwa M.,Abdel-Hamid, Hamida,Teleb, Mohamed
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- A facile approach to synthesize 3,5-disubstituted-1,2,4-oxadiazoles via copper-catalyzed-cascade annulation of amidines and methylarenes
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Various 3,5-disubstituted-1,2,4-oxadiazoles are smoothly formed via copper-catalyzed cascade annulation of amidines and methylarenes. This tandem oxidation-amination-cyclization transformation represents a straightforward protocol to prepare 1,2,4-oxadiazoles from easily available starting materials, with inexpensive copper catalysts and green oxidants. It has the advantages of atom- and step-economy, good functional group tolerance, as well as operational simplicity.
- Guo, Wei,Huang, Kunbo,Ji, Fanghua,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 8857 - 8860
(2015/05/20)
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- Mild and efficient one-pot synthesis of 3,5-disubstituted 1,2,4-oxadiazoles from nitriles mediated by K 3PO 4
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Potassium phosphate, K3PO4, has been proved to be a cheap, strong, and efficient reagent for the one-pot synthesis of 3,5-disubstituted-1,2,4-oxadiazoles from nitriles and acid chlorides under mild conditions. [Supplementary material
- Movassagh, Barahman,Talebsereshki, Farzaneh
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supporting information
p. 188 - 194
(2013/12/04)
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- A metal-free tandem approach to prepare structurally diverse N-heterocycles: Synthesis of 1,2,4-oxadiazoles and pyrimidinones
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A metal-free one-pot approach to the diversity oriented synthesis of N-heterocycles, 1,2,4-oxadiazoles and 2,6 disubstituted pyrimidin-4-ones is described via carboxamidation of amidines with aryl carboxylic acids and aryl propargylic acids. The reactions occur at room temperature forming N-acylamidines which undergo tandem nucleophilic addition-deamination- intramolecular cyclisation to give the corresponding heterocyclic compounds in good to excellent yields. This one pot approach has led to the successful synthesis of the drug lead molecule, ataluren, 3-(5-(2-fluorophenyl)-1,2,4- oxadiazol-3-yl) benzoic acid in two steps. the Partner Organisations 2014.
- Gupta, Puneet K.,Hussain, Mohd. Kamil,Asad, Mohd.,Kant, Ruchir,Mahar, Rohit,Shukla, Sanjeev K.,Hajela, Kanchan
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p. 3062 - 3070
(2014/07/07)
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- Construction of 3,5-substituted 1,2,4-oxadiazole rings triggered by tetrabutylammonium hydroxide: A highly efficient and fluoride-free ring closure reaction of O-acylamidoximes
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Tetrabutylammonium hydroxide (TBAH) is an efficient and mild alternative to tetrabutylammonium fluoride (TBAF) for base catalyzed cyclizations of 1,2,4-oxadiazoles from O-acylamidoximes. For most 3,5-substituted 1,2,4-oxadiazoles the reactions were dramatically accelerated by addition of 0.1 equiv of TBAH at room temperature. This method was also more generally applicable allowing for a wider range of substrates. Additionally, due to the absence of fluoride, TBAH will not result in corrosion of reactor vessels and therefore is better suited for large-scale synthesis.
- Otaka, Hiromichi,Ikeda, Junya,Tanaka, Daisuke,Tobe, Masanori
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p. 979 - 981
(2014/02/14)
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- Construction of 3,5-substituted 1,2,4-oxadiazole rings triggered by tetrabutylammonium hydroxide: A highly efficient and fluoride-free ring closure reaction of O-acylamidoximes
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Tetrabutylammonium hydroxide (TBAH) is an efficient and mild alternative to tetrabutylammonium fluoride (TBAF) for base catalyzed cyclizations of 1,2,4-oxadiazoles from O-acylamidoximes. For most 3,5-substituted 1,2,4-oxadiazoles the reactions were dramatically accelerated by addition of 0.1 equiv of TBAH at room temperature. This method was also more generally applicable allowing for a wider range of substrates. Additionally, due to the absence of fluoride, TBAH will not result in corrosion of reactor vessels and therefore is better suited for large-scale synthesis.
- Otaka, Hiromichi,Ikeda, Junya,Tanaka, Daisuke,Tobe, Masanori
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p. 979 - 981
(2015/02/02)
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- Reaction of oximes of-diketones with diphosphorous tetraiodide for preparation of oxadiazoles and nitriles
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The utility of diphosphorous tetraiodide as a new, mild, condensing agent for synthesis of oxadiazole is described. These data indicate the simple dehydration of oximes to 1,2,5-oxadiazole as well as the rearrangements of oximes to normal Beckmann product 1,2,4-oxadiazole. However, mono-oxime of benzil undergoes abnormal Beckman rearrangement to benzaldehyde as major product. The described method is simple and important for the synthesis of the oxadiazoles as well as for nitriles.
- Telvekar, Vikas N.,Takale, Balaram S.
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p. 221 - 227,7
(2020/09/02)
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- Condensed oxaziridine-mediated [3+2] cycloaddition: Synthesis of polyhetero-bicyclo compounds
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Polyhetero-bicyclo compounds were synthesized by a regioselective [3+2]-cycloaddition reaction between stable condensed oxaziridines and alkenes, alkynes, and nitriles. These molecules showed considerable antimicrobial activity against several gram-positive bacteria.
- Videtta, Valeria,Perrone, Serena,Rosato, Francesca,Alifano, Pietro,Tredici, Salvatore M.,Troisi, Luigino
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scheme or table
p. 2781 - 2783
(2010/12/25)
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- POSITIVE ALLOSTERIC MODULATORS OF THE NICOTINIC ACETYLCHOLINE RECEPTOR
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The invention provides compounds of Formula (I). These compounds may be in the form of pharmaceutical salts or compositions, may be in pure enantiomeric form or racemic mixtures, and are useful in pharmaceuticals used to treat diseases or conditions in wh
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- Synthesis of 3,5-disubstituted-1,2,4-oxadiazoles using tetrabutylammonium fluoride as a mild and efficient catalyst
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Tetrabutylammonium fluoride (TBAF) was found to be a mild and efficient catalyst for the synthesis of 3,5-disubstituted-1,2,4-oxadiazoles. Using 0.1 - 1.0 equivalents of TBAF in THF for 1 - 24 h at room temperature, alkanoyl- and aroyloxyamidines were converted in high yield to the corresponding 3,5-disubstituted-1,2,4-oxadiazoles. A variety of R and R′ substituents were investigated.
- Gangloff, Anthony R.,Litvak, Joane,Shelton, Emma J.,Sperandio, David,Wang, Vivian R.,Rice, Kenneth D.
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p. 1441 - 1443
(2007/10/03)
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- Reactions of Oximes with Thianthrene Cation Radical in Nitrile Solvents. Cycloaddition To Form Oxadiazoles and Deoxygenation To Form Nitriles
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Reactions of eight oximes, RCH=NOH (1a, R= C6H5; 1b, R= 4-CH3C6H4; 1c, R= 4-NO2C6H4; 1d, R= 4-CH3OC6H4; 1e, R= 2-CH3OC6H4; 1f, R= 1-naphthyl; 1g, R= C5H11; 1h, R= C4H9), with thianthrene cation radical perchlorate (Th.+ClO4-) in acetonitrile under argon were studied.The major product from the oxime in all cases, but of 1d, was the nitrile, RCN.The anticipated product of oxidative cycloaddition, namely, a 3-R-5-methyl-1,2,4-oxadiazole (2), was obtained in substantial yield (2d, 66percent) only in the case of 1d.An isomeric 5-R-3-methyl-1,2,4-oxadiazole (3) was obtained from some reactions, that is, 3c alone from 1c, and a mixture of 2a and 3a from 1a.Neither 2 nor 3 was obtained in measurable amounts from reactions of 1g and 1h.The aldehyde (RCHO) was obtained in small yields from each reaction.Thianthrene (Th) and thianthrene 5-oxide (ThO) were also major products.Studies with -1b and -1d showed that the oxgen atom in 2 came entirely and in ThO primarily from the oxime.Studies of workup with H218O showed that the workup water was the source of the oxgen atom in RCHO and to a small extent in ThO.Explanations are given for the formation of 2 by a stepwise addition of RCH=NOH.+ (1.+) to solvent nitrile and of 3 by the reaction of solvent nitrile with an oxaziridine cation radical (7, obtained from 1.+).
- Chiou, Shishue,Hoque, A. K. M. M.,Shine, Henry J.
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p. 3227 - 3232
(2007/10/02)
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- A Simplified Procedure for Preparing 3,5-Disubstituted-1,2,4-Oxadiazoles by Reaction of Amidoximes with Acyl Chlorides in Pyridine Solution
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3-R-5-R'-1,2,4-Oxadiazoles are prepared in fair to good yield by short-time, one-pot reaction of an amidoxime, RC(NH2)NOH, with an acyl chloride, R'COCl, in pyridine solution.Precipitation of the oxadiazole occurs on diluting the pyridine reaction solutio
- Chiou, Shishue,Shine, Henry J.
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p. 125 - 128
(2007/10/02)
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- Amidrazones. 8 . Synthesis of 1,2,4-Oxadiazoles by Thermolysis of N3-Acylamidrazone Ylides
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N3-Acylamidrazone ylides 3 were synthesized by the reaction of 2-(iminophenylmethyl)-1,1,1-trimethylhydrazinium hydroxide, inner salt (2a) or 2-(1-iminoethyl)-1,1,1-trimethylhydrazinium hydroxide, inner salt (2b) with acyl chlorides or acetic anhydride.Thermolysis of 3 gave 3,5-disubstituted oxadiazoles 4 and trimethylamine.
- Smith, Richard F.,Coffman, Karen J.,Geer, Susan M.
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- Formation and Thermal Reaction of O-(N-Acetylbenzimidoyl)benzamidoxime: Comparison with the Formation of 3,5-Disubstituted 1,2,4-Oxadiazoles from O-Acetylarylamidoximes and O-Aroylacetamidoximes
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Salts of O-(benzimidoyl)benzamidoxime have been obtained by the action of N-chloro- or N-bromo-succinimide, or the halogens, on benzamidoxime.Acetylation of the free base gave the title compound, which underwent a thermal cyclisation, with loss of acetamide, to give 3,5-diphenyl-1,2,4-oxadiazole.The mechanism of the reaction, in diphenyl ether, closely paralleled the thermal cyclisation of O-acetylarylamidoximes and O-aroylacetamidoximes, and is thought to involve a polar cyclisation step followed by rate-determining proton transfer. 13C N.m.r. spectra for 32 oxime, amidoxime, O-acetylamidoxime, 5-methyl-1,2,4-oxadiazol-3-yl, and 3-methyl-1,2,4-oxadiazol-5-yl groups on the phenyl ring are calculated.
- Ooi, Ngan Sim,Wilson, David A.
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p. 1792 - 1799
(2007/10/02)
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