- Fragmentation and skeletal rearrangements of 2-arylylamino-5-aryl-1,3,4- oxadiazoles and their noncovalent complexes with cobalt cation and cyclodextrin studied by mass spectrometry
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Mass spectrometric fragmentation pathways of title compounds were studied by electron ionization (EI) and electrospray ionization (ESI) as methods of ion generation. To explain the observed complex skeletal rearrangements, tandem mass spectrometry, accurate mass measurement and isotope labeling (compounds containing one 13C atom in oxadiazole ring) were used. Loss of CO, N2 and H atoms under EI conditions led to the formation of 9,10-dihydroacridine-type ions, loss of NH3 under ESI conditions yielded the 4-phenylphthalazinone-type ions and the loss of HNCO under ESI conditions produced N-arylamino-benzonitrilium ions; however, this process can be affected by the electron-donor/electron-withdrawing properties of groups substituted at the phenyl rings. The ESI was used to study the complexes of the compounds with cobalt as well as with cyclodextrin. It was found that the compounds studied tend to form inclusion complexes with cyclodextrin of stoichiometry 1:1 and complexes of different stoichiometries with cobalt, although those of stoichiometry 6:1 and 4:1 are favored and the attachment of counter ion may stabilize the complexes 3:1 and 2:1. Copyright
- Franski, Rafal,Gierczyk, Blazej,Schroeder, Grzegorz
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Read Online
- 15N NMR study of substituted 2-(phenylamino)-5-phenyl-1,3,4- oxadiazoles
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Substituted 2-(phenylamino)-5-phenyl-1,3,4-oxadiazoles were studied by 15N NMR spectroscopy. All signals were assigned on the basis of HMQC and HMBC experiments. Chemical shifts values were correlated with empirical Hammett parameters as well a
- Gierczyk, Blazej,Nowak-Wydra, Barbara,Grajewski, Jakub,Zalas, Maciej
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Read Online
- A KHSO4 mediated facile synthesis of 2-amino-1,3,4-oxadiazole derivatives
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A novel, efficient and mild KHSO4 mediated synthesis for 2-amino-1,3,4-oxadiazoles has been established via the cyclodesulfurization of benzoylhydrazine and isothiocyanate derivatives in one pot. The reactions proceeded smoothly at room tempera
- Gan, Zongjie,Han, Lei,Hu, Xiangnan,Long, Binyu,Tang, Qiang,Tian, Binghua,Wang, Chenyu,Wang, Zifan,Wu, Yue,Yu, Yu
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supporting information
(2021/08/18)
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- Preparation method of 2-amino-1, 3, 4-oxadiazole compound and prepared compound
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The invention belongs to the field of medical chemistry, and particularly relates to a preparation method of a 2-amino-1, 3, 4-oxadiazole compound and the compound prepared by the preparation method. According to the method, the 1, 3, 4-oxadiazole compoun
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Paragraph 0028-0035
(2021/08/28)
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- 2-Amino-substituted oxadiazole derivatives and pharmaceutical composition comprising the same
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The present invention provides: a novel 2-amino-substituted oxadiazole derivative represented by Chemical Formula 1 and having an excellent Wnt gene expression controlling activity; a pharmaceutically allowable salt of the same; a method for producing the
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Paragraph 0069; 0070; 0073; 0074
(2016/11/21)
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- Novel 1,3,4-oxadiazole motifs bearing a quinoline nucleus: Synthesis, characterization and biological evaluation of their antimicrobial, antitubercular, antimalarial and cytotoxic activities
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A series of quinoline based 1,3,4-oxadiazole derivatives (8a-l) were synthesized by a chloro-amine coupling reaction approach with different catalysts and solvents. Substituted 1,3,4-oxadiazole intermediates 7a-c were obtained from 2-substituted-N-phenylh
- Ladani, Gaurav G.,Patel, Manish P.
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p. 9848 - 9857
(2015/12/01)
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- Efficient and mild synthesis of substituted 2-amino-1,3,4-oxadiazoles mediated by (tosylimino)phenyl-γ3-iodane
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A simple and convenient one-pot protocol for the synthesis of substituted 2-amino-1,3,4-oxadiazoles mediated by (tosylimino)phenyl-γ3- iodane has been described. Acylthiosemicarbazides prepared from the corresponding acylhydrazides undergo effi
- Prabhu, Girish,Madhu, Chilakapathi,Sureshbabu, Vommina V.
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p. 865 - 870
(2014/08/05)
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- Cyclodesulfurization of Substituted Thiosemicarbazides into 1,3,4-Oxadiazoles via Hydrazonoyl Chlorides
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The reaction of thiosemicarbazides 1a-h with hydrazonoyl chlorides 2a-g at ambient temperature, in the presence of triethylamine yielded, in each case, two products. The structure of these compounds was confirmed as 1,3,4-oxadiazoles 14a-h and hydrazonoth
- Abdel-Aziz, Hatem A.,Bhat, Mashooq A.,Ghazzali, Mohamed
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p. 1328 - 1336
(2015/11/02)
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- Regioselective synthesis of 2-amino-substituted 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives via reagent-based cyclization of thiosemicarbazide intermediate
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A regioselective, reagent-based method for the cyclization reaction of 2-amino-1,3,4-oxadiazole and 2-amino-1,3,4-thiadiazole core skeletons is described. The thiosemicarbazide intermediate 3 was reacted with EDC·HCl in DMSO or p-TsCl, triethylamine in N-
- Yang, Seung-Ju,Lee, Seok-Hyeong,Kwak, Hyun-Jung,Gong, Young-Dae
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p. 438 - 444
(2013/04/10)
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- A new and efficient synthesis of 1,3,4-oxadiazole derivatives using TBTU
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An efficient method for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles from isothiocyanates and hydrazides through cyclodesulfurization in the presence of (O-(benzotriazol-1-yl)-N,N,N′, N′-tetramethyluronium tetrafluoroborate) TBTU as an uronium cou
- Maghari, Shokoofeh,Ramezanpour, Sorour,Darvish, Fatemeh,Balalaie, Saeed,Rominger, Frank,Bijanzadeh, Hamid Reza
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p. 2075 - 2080
(2013/03/13)
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- Oxadiazoles in medicinal chemistry
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Oxadiazoles are five-membered heteroaromatic rings containing two carbons, two nitrogens, and one oxygen atom, and they exist in different regioisomeric forms. Oxadiazoles are frequently occurring motifs in druglike molecules, and they are often used with the intention of being bioisosteric replacements for ester and amide functionalities. The current study presents a systematic comparison of 1,2,4- and 1,3,4-oxadiazole matched pairs in the AstraZeneca compound collection. In virtually all cases, the 1,3,4-oxadiazole isomer shows an order of magnitude lower lipophilicity (log D), as compared to its isomeric partner. Significant differences are also observed with respect to metabolic stability, hERG inhibition, and aqueous solubil ity, favoring the 1,3,4-oxadiazole isomers. The difference in profile between the 1,2,4 and 1,3,4 regioisomers can be rationalized by their intrinsically different charge distributions (e.g., dipole moments). To facilitate the use of these heteroaromatic rings, novel synthetic routes for ready access of a broad spectrum of 1,3,4-oxadiazoles, under mild conditions, are described.
- Bostr?m, Jonas,Hogner, Anders,Llinàs, Antonio,Wellner, Eric,Plowright, Alleyn T.
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experimental part
p. 1817 - 1830
(2012/05/05)
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- O -iodoxybenzoic acid mediated oxidative desulfurization initiated domino reactions for synthesis of azoles
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A systematic exploration of thiophilic ability of o-iodoxybenzoic acid (IBX) for oxidative desulfurization to trigger domino reactions leading to new methodologies for synthesis of different azoles is described. A variety of highly substituted oxadiazoles, thiadiazoles, triazoles, and tetrazoles have been successfully synthesized in good to excellent yields, starting from readily accessible thiosemicarbazides, bis-diarylthiourea, 1,3-disubtituted thiourea, and thioamides.
- Chaudhari, Pramod S.,Pathare, Sagar P.,Akamanchi, Krishnacharaya G.
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experimental part
p. 3716 - 3723
(2012/06/16)
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- A new convenient synthesis of 5-aryl-2-(arylamino)-1,3,4-oxadiazole derivatives
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Electrical energy offers numerous benefits for conducting a synthesis, including increased reaction rates, yield enhancements and cleaner chemistries. 5-Aryl-2-(arylamino)-1,3,4-oxadiazoles were synthesized directly from acylthiosemicarbazide on the plati
- Kumar, Sanjeev
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experimental part
p. 216 - 220
(2012/08/29)
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- A novel strategy for the construction of azole heterocycles via an oxidative desulfurization approach using iodobenzene and oxone
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The oxidative desulfurization approach has been utilized for the construction of oxadiazole and thiadiazole heterocycles using iodobenzene and Oxone. The use of iodobenzene and the inexpensive readily available oxidant Oxone makes the reaction system simp
- Patel, Kavitkumar N.,Jadhav, Nikhil C.,Jagadhane, Prashant B.,Telvekar, Vikas N.
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experimental part
p. 1970 - 1972
(2012/10/07)
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- Hypervalent iodine(V) mediated mild and convenient synthesis of substituted 2-amino-1,3,4-oxadiazoles
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A simple protocol for the synthesis of 2-amino-1,3,4-oxadiazoles starting from the corresponding acylhydrazides by cyclodesulfurization of intermediate acylthiosemicarbazides mediated by o-iodoxybenzoic acid in good yields has been described. The protocol
- Prabhu, Girish,Sureshbabu
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experimental part
p. 4232 - 4234
(2012/09/07)
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- Desulfurization strategy in the construction of azoles possessing additional nitrogen, oxygen or sulfur using a copper(I) catalyst
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A tandem and convergent approach to various N-, O-, or S-containing azoles has been developed by exploiting the thiophilic property of copper( I) iodide used in a catalytic quantity. The present protocol gives access to amino-substituted tetrazoles, triazoles, oxadiazoles and thiadiazoles via oxidative desulfurization of their respective precursors followed by inter- or intramolecular attack of suitable nucleophiles. For aminotetrazoles and triazoles an excellent regioselectivity has been achieved through proper tuning of the pKa values of the parent amines attached to unsymmetrical thioureas. The method represents an autocatalytic process in which copper( I) iodide gets converted to copper(II) sulfide which in turn transforms to active copper(II) oxide that effectively carries forward the catalytic cycle. The fate of the copper catalyst has also been studied using scanning electron microscopic (SEM) and energy-dispersive X-ray spectroscopic (EDS) analyses which give an insight into the mechanism for this catalytic process.
- Guin, Srimanta,Rout, Saroj Kumar,Gogoi, Anupal,Nandi, Shyamapada,Ghara, Krishna Kanta,Patel, Bhisma K.
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p. 2757 - 2770
(2013/01/15)
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- A novel and facile environmentally benign oxidative electrocyclization of acylthiosemicarbazone into biodynamic 1,3,4-oxadiazoles
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A novel, facile and green oxidative electrocyclization of the acylthiosemicarbazone into 5-substituted-2-amino(substituted)-1,3,4-oxadiazoles at platinum electrode using acetonitrile as non-aqueous solvent and lithium perchlorate as supporting electrolyte
- Sharma, Laxmi Kant,Singh, Sushma,Siddiqui,Singh
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experimental part
p. 155 - 161
(2012/03/26)
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- Phosphonium-mediated cyclization of N-(2-aminophenyl)thioureas: Efficient synthesis of 2-aminobenzimidazoles
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BOP efficiently promoted the phosphonium-mediated cyclization of thioureas, leading to a convenient synthesis of 2-aminobenzimidazoles. Compared to conventional methods, the reactions were complete at room temperature with times ranging from a few minutes
- Wan, Zhao-Kui,Ousman, Erena Farah,Papaioannou, Nikolaos,Saiah, Eddine
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scheme or table
p. 4149 - 4152
(2011/09/19)
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- Synthesis of 2-amino-1,3,4-oxadiazoles from isoselenocyanates via cyclodeselenization
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An efficient one-pot method to access 2-amino-1,3,4-oxadiazoles from isoselenocyanates and hydrazides or dihydrazides was developed via cyclodeselenization. Without any harsh reagents, various 2-amino-1,3,4- oxadiazoles were obtained in considerably high
- Xie, Yuanyuan,Liu, Junli,Yang, Ping,Shi, Xiangjun,Li, Jianjun
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experimental part
p. 5369 - 5374
(2011/07/31)
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- Discovery of novel GSK-3β inhibitors with potent in vitro and in Vivo activities and excellent brain permeability using combined ligand- and structure-based virtual screening
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Dysregulation of glycogen synthase kinase (GSK-3β) is implicated in the pathophysiology of many diseases, including type-2 diabetes, stroke, Alzheimers, and others. A multistage virtual screening strategy designed so as to overcome known caveats arising from the considerable flexibility of GSK-3β yielded, from among compounds in our in-house database and two commercial databases, new GSK-3β inhibitors with novel scaffold structures. The two most potent and selective validated hits, a 2-anilino-5-phenyl-1,3,4- oxadiazole (24) and a phenylmethylene hydantoin (28), both exhibited nanomolar affinity and selectivity over CDK2 and were potent enough for direct in vivo validation. Both were able to cause significant increases in liver glycogen accumulation in dose-dependent fashion. One also exhibited excellent blood-brain barrier permeability, the other adequate for a lead compound. Analogues of the oxadiazole 24 were synthesized to experimentally corroborate or rule out ligand-bound structures arising from docking studies. SAR results supported one docking study among a number of alternatives.
- Khanfar, Mohammad A.,Hill, Ronald A.,Kaddoumi, Amal,El Sayed, Khalid A.
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experimental part
p. 8534 - 8545
(2011/02/26)
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- Tetrazoles: LV. Perparation of 2-anilino-5-aryl(hetaryl)-1,3,4-oxadiazoles from 5-substituted tetrazoles under microwave activation
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In reaction of 5-aryl(hetaryl)tetrazoles with phenyl isocyanate under the conditions of microwave activation the corresponding 2-anilino-5-aryl(hetaryl)- 1,3,4-oxadiazoles formed in high yields. The application of the microwave activation fourfold reduced
- Efimova, Yu. A.,Karabanovich,Artamonova,Koldobskii
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scheme or table
p. 1241 - 1244
(2010/03/24)
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- Efficient phosphonium-mediated synthesis of 2-amino-1,3,4-oxadiazoles
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We present an efficient, room temperature procedure for the preparation of 2-amino-1,3,4-oxadiazoles. Oxadiazol-2-ones can be activated for SnAr substitution using phosphonium reagents (e.g., BOP). This approach provides convenient access to N,
- Levins, Christopher G.,Wan, Zhao-Kui
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supporting information; experimental part
p. 1755 - 1758
(2009/04/12)
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- Efficient one-pot synthesis of substituted 2-amino-1,3,4-oxadiazoles
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A convenient one-pot method for the preparation of substituted 2-amino-1,3,4-oxadiazoles has been developed. The method is a significant improvement over previously reported syntheses. Reaction of carboxylic acids with thiosemicarbazides afforded the corresponding oxadiazoles in moderate to good yields. In general, the products precipitated from the reaction mixture, and were collected by filtration. In most of the cases, no chromatographic separations were required. To explore the scope and limitations of this reaction, various aliphatic, aromatic, and heteroaromatic carboxylic acids were reacted with different substituted thiosemicarbazides. The influence of R1 and R2 substituents on the reaction yield and additional results demonstrating the versatility of this method are presented.
- Piatnitski Chekler, Eugene L.,Elokdah, Hassan M.,Butera, John
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supporting information; scheme or table
p. 6709 - 6711
(2009/04/07)
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- New access to pyrazole, oxa(thia)diazole and oxadiazine derivatives
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1,4-Disubstituted thiosemicarbazides 1b-f reacted with ethenetetracarbonitrile (5) in dimethylformamide with formation of 2-substituted 5-phenyl-1,3,4-thiadiazoles 2a-f and 2-substituted 5-phenyl-1,3,4-oxadiazoles 4a-f. Upon addition of 5 to 1c-e in chlorobenzene, 3-amino-2-benzoyl-4,5,5- tricyano-2,5-dihydro-1H-pyrazole- 1-[N-(4-tricyanovinyl)phenyl]carbothioamide (12), 5-benzylamino-, and 5-allylamino-4-benzoyl-2,3-dihydro-[1,3,4]thiadiazol- 2,2-dicarbonitrile (13a,b) and 5-amino-1-benzoylpyrazole-3,4-dicarbonitrile (14) as well as 2-phenyl-4H-[1,3,4]-oxadiazine-5,6-dicarbonitrile (15) were formed. Rationales for the role of the solvent and the conversions observed are presented.
- Hassan, Alaa A.,El-Shaieb, Kamal M.,Shaker, Raafat M.,Doepp, Dietrich
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- The rapid preparation of 2-aminosulfonamide-1,3,4-oxadiazoles using polymer-supported reagents and microwave heating
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Herein, we report on the preparation of a library of 5-substituted-2-amino- 1,3,4-oxadiazoles and the corresponding thiadiazole analogues. Presented is a one-pot preparation of the 2-aminosulfonylated analogues through a three component coupling of an acylhydrazine, an isocyanate and sulfonyl chloride promoted by a polymer-supported phosphazine base under microwave dielectric heating. Also described is the optimization process and details pertaining to the elucidation of the reaction products.
- Baxendale, Ian R.,Ley, Steven V.,Martinelli, Marisa
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p. 5323 - 5349
(2007/10/03)
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- Efficient one-pot preparation of 5-substituted-2-amino-1,3,4-oxadiazoles using resin-bound reagents
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A robust one-pot solution-phase synthesis of 2-amino-1,3,4-oxadiazoles directly from acylhydrazines and isothiocyanates is described. Commercially-available polymer-supported reagents help facilitate both cyclization and purification. This convenient meth
- Coppo, Frank T.,Evans, Karen A.,Graybill, Todd L.,Burton, George
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p. 3257 - 3260
(2007/10/03)
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- An efficient synthesis of 1,3,4-oxadiazoles from N,N′-diacylhydrazines using Ph3P·Br2, Ph3P·CCl4 or Ph3P·CBr4 adducts as condensing agents
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1,3,4-Oxadiazoles including 2-amino derivatives were effectively synthesized by treatment of N,N′-diacylhydrazines or N-acylsemicarbazides with Ph3P·Br2, Ph3P·CCl4 or Ph3P·CBr4 adducts in the presence of Et3N in CH2Cl2 under mild conditions.
- Mazurkiewicz,Grymel
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- A SYNTHESIS OF 1,3,4-OXADIAZOLES VIA THE AZA-WITTIG REACTION OF N-ACYLAMINO IMINOTRIPHENYLPHOSPHORANES
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The aza-Wittig reaction of N-acylamino iminotriphenylphosphoranes with carbon disulfide, isocyanates and isothiocyanates, lead to the very reactive heterocumulenic systems (5) and (2) which undergo spontaneous cyclization to 5-substituted 2-mercapto-1,3,4-oxadiazoles (6) and 2-amino-1,3,4-oxadiazoles (3), respectively.
- Froeyen, Paul
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- Heterocyclic Photorearrangements. Photochemical Behaviour of Some 3,5-Disubstituted 1,2,4-Oxadiazoles in Methanol at 254 nm
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Photochemical behaviour of some 3,5-disubstituted 1,2,4-oxadiazoles in methanol at 254 nm has been investigated.Ring photoisomerization to the 1,3,4-oxadiazole heterocycle or formation of open chain compounds involving the nucleophilic solvent was shown to depend on the nature and the position of the substituent.Photoinduced ring closure into the benzimidazole system, involving a 3-N-phenylamino side chain sequence and a photolytic intermediate of the oxadiazole heterocycle, is also reported.
- Buscemi, Silvestre,Cicero, Maria G.,Vivona, Nicolo,Caronna, Tullio
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p. 931 - 935
(2007/10/02)
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- Thermal Ring Transformation of 5-Aryl-2-carbazoyl-1,2,3,4-tetrazole Derivatives
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Unstable 5-aryl-2-(3-benzylidene-2-phenylcarbazoyl)-1,2,3,4-tetrazoles 8 have been prepared.By thermal ring transformation, they gave 5-aryl-2-(2-benzylidene-1-phenylhydrazino)-1,3,4-oxadiazoles 9.Hydrazinolysis of 9 afforded 5-aryl-2-(1-phenylhydrazino)-
- Milcent, Rene,Barbier, Geo
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p. 1233 - 1234
(2007/10/02)
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- Dihalogentriphenylphosphoranes in Heterocyclic Synthesis; 15. A Simple One-Pot-Procedure for the Generation of Nitrilimines with the Aid of Dihalogentriphenylphosphoranes: 1,3-Dipolar Cycloadditions and 1,5-Electrocyclizations
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A simple and versatile one-pot procedure for the in situ generation of nitrilimines from N-acyl hydrazines is described. 1,3-Dipolar cycloadditions and 1,5-electrocyclic ring closures are carried out.Unsymmetrically substituted dipolarophiles show typical
- Wamhoff, Heinrich,Zahran, Magdy
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p. 876 - 879
(2007/10/02)
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