19932-97-9Relevant academic research and scientific papers
Kinetics of base-catalysed hydrolysis and cyclisation of substituted acetamide and benzamide O-(phenoxycarbonyl)oximes
Mindl, Jaromir,Kavalek, Jaromir,Strakova, Helena,Sterba, Vojeslav
, p. 1641 - 1653 (1999)
The reaction kinetics of acetamide O-(4-nitrophenoxycarbonyl)oxime have been studied in aqueous buffers at pH 2-11. At pH > 9, the pH dependence of kobs is linear with slope 1, the cyclisation to 3-methyl-1,2,4-oxadiazol-5(4H)-one and 4-nitrophenol being the only reaction. At pH obs on pH has been used to determine the rate equation and to propose the reaction mechanism. The cyclisation kinetics of substituted benzamide O-(phenoxycarbonyl)oximes have been studied in the pH range from 9.25 to 11. The reaction mechanism has been proposed based on the ρ constants found. In the first reaction step, the proton is split off from the NH2 group; the subsequent, rate-limiting step involves simultaneous N-C bond formation and C-O bond splitting.
Copper-Catalyzed Selective N-Arylation of Oxadiazolones by Diaryliodonium Salts
Soldatova, Natalia S.,Semenov, Artem V.,Geyl, Kirill K.,Baykov, Sergey V.,Shetnev, Anton A.,Konstantinova, Anna S.,Korsakov, Mikhail M.,Yusubov, Mekhman S.,Postnikov, Pavel S.
supporting information, p. 3566 - 3576 (2021/06/16)
Here, we report the method for copper-catalyzed N-arylation of diverse oxadiazolones by diaryliodonium salts under mild conditions in high yields (up to 92%) using available CuI as a catalyst. The developed method allows utilizing both symmetric and unsymmetric diaryliodonium salts bearing auxiliary groups such as 2,4,6-trimethoxyphenyl (TMP). We found that the steric effects in aryl moieties determined the chemoselectivity of N- and O-arylation of the 1,2,4-oxadiazol-5(4H)-ones. Mesityl-substituted diaryliodonium salts demonstrated the high potential as a selective arylation reagent. The structural study suggests that steric accessibility of N-atom in 1,2,4-oxadiazol-5(4H)-ones impact to arylation with sterically hindered diaryliodonium salts. The synthetic application of proposed method was also demonstrated on selective arylation of 1,3,4-oxadiazol-2(3H)-ones and 1,2,4-oxadiazole-5-thiol. (Figure presented.).
Rh(II)-Catalyzed Transannulation of 1,2,4-Oxadiazole Derivatives with 1-Sulfonyl-1,2,3-triazoles: Regioselective Synthesis of 5-Sulfonamidoimidazoles
Strelnikova, Julia O.,Rostovskii, Nikolai V.,Starova, Galina L.,Khlebnikov, Alexander F.,Novikov, Mikhail S.
, p. 11232 - 11244 (2018/09/06)
An effective method for the synthesis of fully substituted 5-sulfonamidoimidazoles by Rh(II)-catalyzed transannulation of 1,2,4-oxadiazole derivatives with N-sulfonyl-1,2,3-triazoles is reported. The reaction works well with both aromatic 1,2,4-oxadiazoles and 1,2,4-oxadiazol-5-ones providing a flexible approach to N-(alkoxy/amino)carbonyl- and N-alkyl-substituted imidazoles. Both the disclosed reactions are completely regioselective and provide the first examples of a carbenoid-mediated transformation of N,N,O-heterocycles.
Green synthesis method of oxadiazole derivatives
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Paragraph 0019; 0035-0038, (2019/01/08)
The invention relates to the field of organic chemistry, overcomes disadvantages in the synthesis of oxadiazole derivatives in the prior art, and provides a green synthesis method of the oxadiazole derivatives. The method comprises the following specific steps: (1) adding a basic reagent, dropwise adding a carbonylation reagent, stirring evenly, and back-flowing at 100 DEG C, wherein water is usedas a solvent, N-hydroxybenzamidine or substituted N-hydroxybenzamidine is used as a raw material, the reaction time is 1-5 hours; and (2) after the reaction is finished, cooling, standing, adjustingpH to 3-4 with 1 mol/L diluted HCl acidification reaction solution, performing suction filtration, collecting filter cakes, washing the filter cakes with water, and performing vacuum drying to finallyobtain the oxadiazole derivative. N-hydroxybenzamidine or substituted N-hydroxybenzamidine and a carbonylation reagent are used as the raw materials, under the action of the basic reagent, the oxadiazole derivatives can be synthesized in one step in water, and the two steps of esterification and cyclization are simplified to one step, thus greatly shortening the reaction time and increasing the reaction yield. The method has the advantages of being mild in reaction conditions, convenient to separate and purify, green and environmentally friendly.
Oxadiazolone-Enabled Synthesis of Primary Azaaromatic Amines
Yu, Xiaolong,Chen, Kehao,Yang, Fan,Zha, Shanke,Zhu, Jin
, p. 5412 - 5415 (2016/11/06)
Despite their tremendous synthetic and pharmaceutical utility, primary azaaromatic amines remain elusive for access based on a generally applicable C-H functionalization strategy. An oxadiazolone-enabled approach is reported for convenient entry into N-unsubstituted 1-aminoisoquinolines through Co(III)-catalyzed redox-neutral, step-, atom-, and purification-economic C-H functionalization with alkynes. A 15N labeling experiment reveals the effectiveness of both oxadiazolone N atoms as directing sites. The installed primary amine can be harnessed as a synthetically useful handle for attachment of divergent appendages.
NH-acidities and Hammett correlation of 3-para substituted phenyl-1,2,4-oxadiazol-5(4H)-ones and 1,2 λ43,5-oxathiadiazole 2-oxides in nonaqueous media
Dueruest, Nedime,Dueruest, Yasar,Goezlukaya, Emine Oezge
, p. 56 - 62 (2014/02/14)
NH acidities of some 3-(p-substitutedphenyl)-1,2,4-oxadiazol-5(4H)-ones and 4-(p-substitutedphenyl)-1,2 λ43,5-oxathiadiazole 2-oxides were determined in methanol by means of potentiometric titration with sodium methoxide. pKa values of the titl
HYDRAZONE DERIVATIVE
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Page/Page column 30, (2010/11/08)
A compound represented by the following formula (I): wherein R1 represents hydrogen, aryl which may have a substituent, a saturated or unsaturated 5- to 7-membered heterocyclic group which may have a substituent, etc.; R2 represents hydrogen, aryl which may have a substituent, a saturated or unsaturated 5- to 7-membered heterocyclic group which may have a substituent, etc.; R3 represents hydrogen, etc.; Ar represents a divalent group derived from aromatic hydrocarbon, etc.; X represents a single bond, linear or branched alkylene having from 1 to 3 carbon atoms which may have a substituent, etc.; and G represents halogen, a saturated or unsaturated 5- or 6-membered cyclic hydrocarbon group which may have a substituent, a saturated or unsaturated 5- to 7-membered heterocyclic group which may have a substituent, etc., a salt thereof or a solvate thereof; and an agent for inhibiting aggregation and/or deposition of an amyloid protein or an amyloid-like protein, which comprises the compound, a salt thereof or a solvate thereof
Heterocycles from Nitrile Oxides. 3. 1,2,4-Oxadiazol-5(4H)-ones
Hussein, Ahmad Q.
, p. 127 - 128 (2007/10/02)
The reaction of nitrile oxides with potassium cyanate gives 3-aryl-1,2,4-oxadiazol-5(4H)-ones (5).These heterocycles are also obtained by cyclization of the corresponding O-carbethoxyamidoximes (7) with sodium ethoxide.
REACTION OF BENZAMIDE OXIME DERIVATIVES WITH CHLOROCARBONYLSULFENYL CHLORIDE
Kawashima, Etsuko,Ando, Yuko,Takada, Toyozo,Tabei, Katsumi
, p. 181 - 190 (2007/10/02)
Benzamide oxime derivatives (1) were reacted with chlorocarbonylsulfenyl chloride (2) in the presence of a base as a catalyst to afford 3-aryl-4,5-dihydro-1,2,4-thiadiazol-5-one (3), 3-aryl-4,5-dihydro-1,2,4-oxadiazol-5-one (4) and di(benzamide) O,O'-carboxime (5) derivatives in moderate yields.The reaction of N-ethyl-p-toluamide oxime (7) with 2 gave 4-ethyl-4,5-dihydro-3-(p-tolyl)-1,2,4-thiadiazol-5-one (8) and 4-ethyl-4,5-dihydro-3-(p-tolyl)-1,2,4-oxadiazol-5-one (9).
