- Direct synthesis of 3,5-diaryl-1,2,4-oxadiazoles using 1-(2-oxo-2-arylethyl)pyridin-1-iums with benzamidines
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An efficient domino protocol for the synthesis of 1,2,4-oxadiazole derivatives from readily available 1-(2-oxo-2-arylethyl)pyridin-1-iums and amidine hydrochlorides was developed. In this practical approach, N-acyl amidine precursors were formed firstly via a simple nucleophilic substitution, without the purification of N-acylamidine intermediates, and the following intramolecularly dehydrative cyclization gave 1,2,4-oxadiazole derivatives in the presence of I2/K2CO3/DMSO, which exhibited excellent functional group tolerance and proceeded under simple experimental conditions.
- Zhang, Yue,Wu, Chengjun,Wan, Xinyi,Wang, Cunde
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p. 2287 - 2297
(2021/08/30)
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- One-pot synthesis of 1,2,4-oxadiazoles from carboxylic acids using 4-(dimethylamino)pyridinium acetate as efficient, regenerable, and green catalyst with ionic liquid character
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A recyclable bifunctional acid-base organocatalyst with ionic liquid character has been prepared and its catalytic activity for the preparation of oxadiazoles has been investigated.
- Nowrouzi, Najmeh,Khalili, Dariush,Irajzadeh, Maryam
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p. 801 - 806
(2015/03/18)
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- Highly efficient one-pot preparation of 1,2,4-oxadiazoles in the presence of diazabicycloundecene
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New highly efficient method for the cyclization of acylamidoximes in the presence of diazabicycloundecene was developed and incorporated into a general and practical one-pot synthesis of 1,2,4-oxadiazoles (11 examples, 85-97% yields).
- Lukin, Kirill,Kishore, Vimal
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p. 256 - 261
(2014/02/14)
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- Microwave-assisted efficient, one-pot, three-component synthesis of 3,5-disubstituted 1,2,4-oxadiazoles under solvent-free conditions
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A novel synthesis of 1,2,4-oxadiazoles is described from a one-pot, three-component reaction between nitriles, hydroxylamine, and aldehydes under microwave irradiation and solvent-free conditions in excellent yields.
- Adib, Mehdi,Jahromi, Amin Haghighat,Tavoosi, Narjes,Mahdavi, Mohammad,Bijanzadeh, Hamid Reza
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p. 2965 - 2967
(2007/10/03)
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- One-pot synthesis of 1,2,4-oxadiazoles from carboxylic acid esters and amidoximes using potassium carbonate
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A convenient one-pot synthesis of 1,2,4-oxadiazoles is described. The condensation of carboxylic acid esters and amidoximes in the presence of potassium carbonate was employed to synthesize a variety of mono-, bis- and tris-oxadiazoles in moderate to exce
- Amarasinghe, Kande K.D.,Maier, Matthew B.,Srivastava, Anil,Gray, Jeffrey L.
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p. 3629 - 3631
(2007/10/03)
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- Parallel synthesis of 1,2,4-oxadiazoles using CDI activation
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1,2,4-Oxadiazoles have been prepared in parallel using 1,1'- carbonyldiimidazole (CDI) as a reagent for both formation and cyclodehydration of O-acyl benzamidoximes. The use of CDI facilitates parallel purification of the oxadiazole products by simple liquid-liquid extraction and filtration.
- Deegan, Tracy L.,Nitz, Theodore J.,Cebzanov, Diane,Pufko, Denise E.,Porco Jr., John A.
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p. 209 - 212
(2007/10/03)
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- An improved oxadiazole synthesis using peptide coupling reagents
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Substituted 1,2,4-oxadiazoles were synthesized in good yields in a one pot procedure by condensation of the corresponding amidoxime with carboxylic acids in the presence of a peptide coupling reagent in diglyme, followed by heating the reaction mixture to 100°C for several hours.
- Liang, Gui-Bai,Feng, Danqing D.
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p. 6627 - 6630
(2007/10/03)
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- CYCLIZATION AND ACID-CATALYZED HYDROLYSIS OF O-BENZOYLBENZAMIDOXIMES
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Kinetics of formation of 1,2,4-oxadiazoles from 24 substitution derivatives of O-benzoylbenzamidoxime have been studied in sulphuric acid and aqueous ethanol media.It has been found that this medium requires introduction of the Hammett H0 function instead of the pH scale beginning as low as from 0.1percent solutions of mineral acids.Effects of the acid concentration, ionic strength, and temperature on the reaction rate and on the kinetic isotope effect have been followed.From these dependences and from polar effects of substituents it was concluded that along with the cyclization to 1,2,4-oxadiazoles there proceeds hydrolysis to benzamidoxime and benzoic acid.The reaction is thermodynamically controlled by the acid-base equilibrium of the O-benzylated benzamidoximes.
- Grambal, Frantisek,Lasovsky, Jan
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p. 2786 - 2797
(2007/10/02)
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