- Neuroprotective evaluation of novel substituted 1,3,4-oxadiazole and aroylhydrazone derivatives
-
The paper reports on the facile and convenient synthesis of a series of novel 2,5-substituted 1,3,4-oxadiazoles 3a-f and that of aroylhydrazone-based molecular hybrids 5a-g from readily available starting materials. The structure of the compounds was confirmed by IR, 1H NMR, 13C NMR and HRESI-MS spectral data. The toxicological potential of the compounds was evaluated by monitoring the synaptosomal viability and the levels of reduced glutathione in rat brain synaptosomes, isolated by Percoll gradient. The neuroprotective effects were assessed in vitro in a model of 6-hydroxydopamine-induced neurotoxicity. Administered alone, at a concentration of 40 μM, most of the 1,3,4-oxadiazole derivatives and all of the hydrazone derivatives exhibited weak statistically significant neurotoxic effects, compared to the control. Two of the compounds from the novel oxadiazoles 3a and 3d did not have any toxicity. In a model of 6-OHDA-induced oxidative stress, again 3a and 3d and all aroylhydrazone derivatives 5a-g revealed statistically significant neuroprotective effect by preserving the synaptosomal viability and the level of reduced glutathione, against the toxic agent. Some of the compounds may have neuroprotective effects due to possible stabilization of the synaptosomal membrane and/or because of the preserved reduced glutathione. Additionally, all the compounds display a good predicted ADME profile.
- Angelova, Violina T.,K.-Yovkova, Elena,Karabeliov, Valentin R.,Kondeva-Burdina, Magdalena S.,Vassilev, Nikolay G.
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supporting information
(2022/01/20)
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- UV-Induced 1,3,4-Oxadiazole Formation from 5-Substituted Tetrazoles and Carboxylic Acids in Flow
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A range of 1,3,4-oxadiazoles have been synthesized using a UV-B activated flow approach starting from carboxylic acids and 5-substituted tetrazoles. The application of UV light represents an attractive alternative to the traditional thermolytic approach and has demonstrated comparable efficiency and versatility, with a diverse substrate scope, including the incorporation of highly substituted amino acids.
- Green, Luke,Livingstone, Keith,Bertrand, Sophie,Peace, Simon,Jamieson, Craig
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supporting information
p. 14866 - 14870
(2020/11/11)
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- Electrochemical Synthesis of 2,5-Disubstituted 1,3,4-Oxadiazoles from α-Keto Acids and Acylhydrazines Under Mild Conditions
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1,3,4-Oxadiazoles are a kind of useful heterocycles which can be frequently found in materials and bioactive molecules. In this study, intermolecular electrochemical cyclization between α-keto acids and acylhydrazines has been developed for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles with the yield up to 91 %. This transformation can be run under mild reaction conditions in the absence of external oxidant, base and transition metal catalyst. Both symmetrical and unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles could be prepared according to the careful choice of the substrate combination. Gram scale synthesis also illustrates the potential application of this protocol in large preparation.
- Lu, Fangling,Gong, Fengping,Li, Liangsen,Zhang, Kan,Li, Zhen,Zhang, Xinwei,Yin, Ying,Wang, Ying,Gao, Ziwei,Zhang, Heng,Lei, Aiwen
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supporting information
p. 3257 - 3260
(2020/05/25)
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- Photocatalyzed facile synthesis of 2,5-diaryl 1,3,4-oxadiazoles with polyaniline-?g-C3N4-TiO2 composite under visible light
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PANI (polyaniline)-g-C3N4-TiO2 composite was prepared and found to be efficient for the synthesis of 2,5-diaryl 1,3,4-oxadiazoles under visible light. This reaction involved decarboxylation and cyclization from α-keto acids with acylhydrazines, and a broad scope of substrates were tolerated to provide the desired products in moderate to good yields. Control experiments indicated that a radical pathway was involved in the present photocatalytic reaction and a synergistic effect may exist in the ternary composite. Moreover, this semiconductor photocatalyst could be readily recovered and showed good reusability with only slight decrease in the catalytic activity after six consecutive runs.
- Wang, Liang,Wang, Yaoyao,Chen, Qun,He, Mingyang
-
supporting information
p. 1489 - 1492
(2018/03/13)
-
- Synthesis of 2,5-disubstituted 1,3,4-oxadiazoles by visible-light-mediated decarboxylation–cyclization of hydrazides and diketones
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A visible-light-induced synthesis of 2,5-disubstituted 1,3,4-oxadiazoles from simple diketones and hydrazides with the assistant of the photocatalyst eosin Y catalyzed decarboxylation and cyclization under mild conditions has been discovered. The reaction tolerates a wide range of functional groups and gives a variety of valuable 1,3,4-oxadiazoles in moderate to good yields. Finally, a plausible reaction mechanism was proposed.
- Diao, Pinhui,Ge, Yanqin,zhang, Wenpei,Xu, Chen,Zhang, Nannan,Guo, Cheng
-
supporting information
p. 767 - 770
(2018/02/07)
-
- METHOD FOR PREPAREING 1,3,4-OXADIAZOL UNDER SOLVENT-FREE CONDITION
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The present invention relates to a synthesis method of 1,3,4-oxadiazol, comprising: 1) under a solvent-free condition and by means of a mechanical pulverization method, making a hydrazide compound react with an aldehyde compound and thereby synthesizing a N-acylhydrazone compound; and 2) under a solvent-free condition, adding an iodine-based oxidizing agent to the N-acylhydrazone compound to synthesize 1,3,4-oxadiazol via oxidative cyclization. The solventless synthesis method of 1,3,4-oxadiazol according to the present invention is easy to perform and handle, and has the advantage of synthesizing 1,3,4-oxadiazol at high selectivity and yield. Also, the solventless synthesis method of the present invention can prevent the formation of side products caused by the minute amount of water that usually remains in solvents, and can further prevent synthesized intermediates from being converted back into the starting materials by the water.COPYRIGHT KIPO 2016
- -
-
Paragraph 0074-0079; 0112-0113; 0202-0203
(2017/02/24)
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- Study on DDQ-promoted synthesis of 2, 5-disubstituted 1, 3, 4-oxadiazoles from acid hydrazides and aldehydes
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A facile stepwise synthesis of 2, 5-disubstituted 1, 3, 4-oxadiazoles proceeding via oxidative cyclization of N-acylhydrazones is reported. The reaction is efficiently promoted by 2, 3-dichloro-5, 6-dicyano-1, 4- benzoquinone (DDQ) to afford the desired products mostly in high yields and in relatively short times. The final 1, 3, 4-oxadiazole derivatives are also synthesized directly from acid hydrazides and aldehydes in a one-pot procedure. The substrate scope and limitations of the reported transformation are discussed in detail.
- Jasiak, Karolina,Kudelko, Agnieszka,Zieliński, Wojciech,Ku?nik, Nikodem
-
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- One-pot cyclization/decarboxylation of α-keto acids and acylhydrazines for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles under transition-metal-free conditions
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A one-pot KI/TBHP-mediated oxidative cyclization of α-keto acids with acylhydrazines was developed. A series of functional 2,5-disubstituted 1,3,4-oxadiazoles were synthesized through a tandem keto amine condensation followed by oxidative cyclization and decarboxylation reactions. This procedure was achieved under transition-metal-free conditions and showed advantages including readily available materials, mild reaction conditions and good group tolerance.
- Gao, Peng,Wang, Juan,Bai, Zijing,Cheng, Hualei,Xiao, Jian,Lai, Mengnan,Yang, Desuo,Fan, Mingjin
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supporting information
p. 4616 - 4619
(2016/09/23)
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- Palladium-Catalyzed Aminocarbonylation Reaction to Access 1,3,4-Oxadiazoles using Chloroform as the Carbon Monoxide Source
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A palladium-catalyzed aminocarbonylation reaction of aryl halides with chloroform and tetrazoles has been developed, where chloroform was employed as the carbon monoxide (CO) source in the presence of cesium hydroxide. The in situ generated N-acylated tetrazoles were unstable and easily decomposed to afford 2,5-disubstituted 1,3,4-oxadiazoles. A wide range of tetrazoles and aryl halides reacted smoothly under the optimized reaction conditions to give the corresponding products in moderate to good yields.
- Li, Zhengyi,Wang, Liang
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p. 3469 - 3473
(2016/01/25)
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- Organocatalytic Oxidative Amidation of Aldehydes with Tetrazoles to Construct 2,5-Diaryl 1,3,4-Oxadiazoles
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A practical and metal-free oxidative amidation of aldehydes with tetrazoles into 1,3,4-oxadiazoles has been developed by employing tetrabutylammonium iodide (TBAI) as catalyst and tert-butyl hydroperoxide (TBHP) as oxidant. A wide range of 2,5-disubstituted 1,3,4-oxadiazoles can be conveniently generated in moderate to good yields. Gram-scale reaction was also realized in this catalytic system..
- Cao, Jing,Wang, Liang
-
supporting information
p. 1239 - 1243
(2015/11/27)
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- Metal-Free Synthesis of 1,3,4-Oxadiazoles from N′-(Arylmethyl)hydrazides or 1-(Arylmethyl)-2-(arylmethylene)hydrazines
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An efficient and versatile metal-free synthesis of 1,3,4-oxadiazoles from N′-(arylmethyl)hydrazides or 1-(arylmethyl)-2-(arylmethylene)hydrazines through oxidative dehydrogenation is reported. A range of 2,5-disubstituted 1,3,4-oxadiazoles were prepared by treating N′-(arylmethyl)hydrazides with (diacetoxyiodo)benzene in acetonitrile or by treating 1-(arylmethyl)-2-(arylmethylene)hydrazines with [bis(trifluoroacetoxy)iodo]benzene in methyl tert-butyl ether. Aldehyde N-acylhydrazones and aldazines were initially generated in situ as intermediates.
- Shang, Zhenhua,Chu, Qianqian,Tan, Sheng
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p. 1032 - 1040
(2015/03/30)
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- Visible-light-promoted aerobic oxidative cyclization to access 1,3,4-oxadiazoles from aldehydes and acylhydrazides
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A novel and practical access to symmetrical and unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles directly from aldehydes and acylhydrazides using visible light irradiation under an air atmosphere in the presence of eosin Y as an organophotoredox catalyst at rt is reported. This is the first example of oxidative cyclization of acylhydrazones employing air and visible light as inexpensive, readily available, non-toxic, and sustainable reagents.
- Yadav, Arvind K.,Yadav, Lal Dhar S.
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supporting information
p. 2065 - 2069
(2014/04/03)
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- Electrosynthesis and screening of novel 1,3,4-oxadiazoles as potent and selective antifungal agents
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The electrochemical oxidation of aldehyde-N-aroylhydrazone has been studied in the presence of NaClO4 as supporting electrolyte in MeOH solution using cyclic voltammetry and controlled potential electrolysis. The results indicate that intramolecular cyclization of aldehyde-N-aroylhydrazone has been successfully performed at a platinum electrode in an undivided cell with good yields of the corresponding 1,3,4-oxadiazoles at ambient conditions. The reaction products were characterized by spectroscopic methods and a mechanism was deduced from voltammetry studies. The antifungal activity of the synthesized compounds was evaluated on Fusarium oxysporum, Alternaria solani, Candida albicans and Aspergillus niger. The results revealed that all the synthesized compounds have significant antifungal activity against the tested fungi. Among the synthesized derivatives 7b, 7d, 7g, 7h, 7i, 7j and 7r were found to be the most effective antifungal compounds. The Royal Society of Chemistry 2013.
- Singh, Sushma,Sharma, Laxmi Kant,Saraswat, Apoorv,Siddiqui, Ibadur R.,Kehri, Harbans K.,Singh, Rana K. Pal
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p. 4237 - 4245
(2013/05/08)
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- Efficient oxidative cyclization of N -acylhydrazones for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles using t-BuOI under neutral conditions
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An efficient procedure for the oxidative cyclization of N -acylhydrazones was developed utilizing tert-butyl hypoiodite (t-BuOI), which is generated in situ from t -BuOCl and NaI. A variety of 2,5-disubstituted 1,3,4-oxadiazoles were synthesized in high yields within short reaction time. The method is also suitable for cyclization of N -acylhydrazones derived from heterocyclic aldehydes and aliphatic aldehydes. Mild reaction conditions and simple workup operations make the procedure a good alternative for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles.
- Gao, Peng,Wei, Yunyang
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p. 113 - 119
(2013/05/23)
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- Efficient oxidative cyclisation of acid hydrazides to 2,5-disubstituted 1,3,4-oxadiazoles catalysed by Bu4NI with t-BuOOH as oxidant
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Acid hydrazides or araldehyde N-acylhydrazones can be converted in good yields to, respectively, symmetrical or unsymmetrical, 2,5-disubstituted 1,3,4-oxadiazoles at 60 °C by a Bu4NI-catalysed procedure which requires the presence of a base and 2.5 equiv. of t-butyl hydroperoxide.
- Gao, Peng,Wei, Yunyang
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p. 506 - 510
(2013/09/12)
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- I2-mediated oxidative C-O bond formation for the synthesis of 1,3,4-oxadiazoles from aldehydes and hydrazides
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A practical and transition-metal-free oxidative cyclization of acylhydrazones into 1,3,4-oxadiazoles has been developed by employing stoichiometric molecular iodine in the presence of potassium carbonate. The conditions of this cyclization reaction also work well with crude acylhydrazone substrates obtained from the condensation of aldehydes and hydrazides. A series of symmetrical and asymmetrical 2,5-disubstituted (aryl, alkyl, and/or vinyl) 1,3,4-oxadiazoles can be conveniently generated in an efficient and scalable fashion.
- Yu, Wenquan,Huang, Gang,Zhang, Yueteng,Liu, Hongxu,Dong, Lihong,Yu, Xuejun,Li, Yujiang,Chang, Junbiao
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p. 10337 - 10343
(2013/11/06)
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- Microwave-assisted one-step synthesis of 2,5-disubstituted-1,3,4- oxadiazoles using 1,4- bis(triphenylphosphonium)-2-butene peroxodisulfate
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A series of 1,3,4-oxadiazoles were efficiently synthesized from the cyclization-oxidation reaction of acyl hydrazones by using 1,4- bis(triphenylphosphonium)-2-butene peroxodisulfate as an oxidant in solvent-free medium under microwave irradiation.
- Gorjizadeh, Maryam,Afshari, Mozhgan,Nazari, Simin
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p. 1627 - 1630
(2014/05/06)
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- Cu(II) catalyzed imine C-H functionalization leading to synthesis of 2,5-substituted 1,3,4-oxadiazoles
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A direct access to symmetrical and unsymmetrical 2,5-disubstituted [1,3,4]-oxadiazoles has been accomplished through an imine C-H functionalization of N-arylidenearoylhydrazide using a catalytic quantity of Cu(OTf)2. This is the first example of amidic oxygen functioning as a nucleophile in a Cu-catalyzed oxidative coupling of an imine C-H bond. These reactions can be performed in air atmosphere and moisture making it exceptionally practical for application in organic synthesis.
- Guin, Srimanta,Ghosh, Tuhin,Rout, Saroj Kumar,Banerjee, Arghya,Patel, Bhisma K.
-
supporting information; experimental part
p. 5976 - 5979
(2012/01/02)
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- A novel, one-pot synthesis of 2,5-disubstituted-1,3,4-oxadiazoles using 1,4-bis(Triphenylphosphonium)-2-butene peroxodisulfate
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An efficient and convenient synthesis of 1,3,4-oxadiazoles from aromatic aldehydes, acyl hydrazide, and 1,4- bis(triphenylphosphonium)-2-butene peroxodisulfate is reported. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.
- Badri, Rashid,Gorjizadeh, Maryam
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experimental part
p. 544 - 549
(2010/06/12)
-
- Synthesis and biological activity test of some new five membered heterocycles
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A new series of 1,3,4-oxadiazoles, 1,2,4-triazoles, 1,3,4-thiadiazoles were synthesized using alkylhydrazides as the starting materials, and then 1,2,4-triazoles were used to synthesize [1,2,4]triazolo[3,4-b][1,3,4] thiadiazoles. All the compounds were evaluated for in vitro antibacterial activity and antitumor activity. A new series of five membered heterocyclic compounds were synthesized using alkylhydrazides as the starting materials. All the compounds were evaluated for in vitro antibacterial activity and antitumor activity.
- Xia, Qingchun,Xu, Dongfang,He, Qizhuang,Li, Xingyu,Sun, Dazhi
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experimental part
p. 2433 - 2440
(2011/10/05)
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- Convenient preparation of unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles promoted by Dess-Martin reagent
-
2,5-Disubstituted 1,3,4-oxadiazoles have been conveniently prepared by oxidative cyclization of N-acyl-N′-aryliden-hydrazines promoted by an excess of Dess-Martin periodinane under mild conditions (23 examples, up to 92% isolated yields).
- Dobrotǎ, Cristian,Paraschivescu, Codru?a C.,Dumitru, Ioana,Matache, Mihaela,Baciu, Ion,Ru?ǎ, Lavinia L.
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scheme or table
p. 1886 - 1888
(2009/07/05)
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- Oxidative cyclization of N-acylhydrazones. Development of highly selective turn-on fluorescent chemodosimeters for Cu2+
-
A series of N-acylhydrazones were synthesised and found to be "turn-on" fluorescent chemodosimeters for Cu2+. Among the tested transition metal ions such as Cu2+, Pb2+, Zn 2+, Cd2+, Hg2+, and Ni2+, a prominent fluorescence enhancement of up to 1000-fold was only observed for Cu2+ in acetonitrile (CH3CN). This was indicated by an onset of unprecedented structured emission. Detailed experiments established that the highly Cu2+ selective fluorescence enhancement resulted from an oxidative cyclization by Cu2+of the originally nonfluorescent N-acylhydrazones into highly fluorescent rigid 1,3,4-oxadiazoles, n-dope type blocks in optoelectronic materials. The chemodosimeters can be applied to sense Cu2+ at nM levels in CH3CN and sub-M levels in neutral aqueous environments, despite a slower response in the latter case. It is expected that these redox-based chemodosimeters might be of general applicability.
- Li, Ai-Fang,He, Hui,Ruan, Yi-Bin,Wen, Zhen-Chang,Zhao, Jin-Song,Jiang, Qiu-Ju,Jiang, Yun-Bao
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experimental part
p. 193 - 200
(2009/04/07)
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- Trichloroisocyanuric acid-mediated one-pot synthesis of unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles at ambient temperature
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An efficient method for the one-pot synthesis of unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles has been developed using trichloroisocyanuric acid (TCCA) at ambient temperature. A wide variety of aromatic as well as heterocyclic aldehydes exhibit condensation with a variety of acylhydrazines followed by oxidative cyclization to yield corresponding unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles. The mild nature of the synthesis and short reaction time are notable advantages of the developed protocol. Copyright Taylor & Francis Group, LLC.
- Pore,Mahadik,Desai
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p. 3121 - 3128
(2008/12/22)
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- Greener and rapid access to bio-active heterocycles: one-pot solvent-free synthesis of 1,3,4-oxadiazoles and 1,3,4-thiadiazoles
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A novel one-pot solvent-free synthesis of 1,3,4-oxadiazoles and 1,3,4-thiadiazoles by condensation of acid hydrazide and triethyl orthoalkanates under microwave irradiations is reported. This green protocol was catalyzed efficiently by solid supported NafionNR50 and phosphorus pentasulfide in alumina (P4S10/Al2O3) with excellent yields.
- Polshettiwar, Vivek,Varma, Rajender S.
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p. 879 - 883
(2008/09/17)
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- 1,3,4-Oxadiazole formation as traceless release in solid phase organic synthesis
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Oxadiazoles were generated upon a dehydrative cyclization reaction with 2-acyl hydrazides bound to the polymeric support via one of their N atoms using TFAA as a dehydration agent.
- Cesarini, Sara,Colombo, Nicoletta,Pulici, Maurizio,Felder, Eduard R.,Brill, Wolfgang K.-D.
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p. 10223 - 10236
(2007/10/03)
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- A facile procedure for the one-pot synthesis of unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles
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Unsymmetrically 2,5-disubstituted 1,3,4-oxadiazoles were efficiently synthesized from the cyclization-oxidation reaction of acyl hydrazones. Also, the synthesis of the title compounds was achieved by the condensation of acyl hydrazides and aromatic aldehydes in the presence of ceric ammonium nitrate in dichloromethane.
- Dabiri, Minoo,Salehi, Peyman,Baghbanzadeh, Mostafa,Bahramnejad, Mahboobeh
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p. 6983 - 6986
(2007/10/03)
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- Oxidative cyclization of aromatic aldehyde n-acylhydrazones by bis(trifluoroacetoxy)iodobenzene
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Aromatic aldehyde N-acylhydrazones were oxidized into 2,5-disubstituted 1,3,4-oxadiazoles with bis(trifluoroacetoxy)iodobenzene in CHCl3 or DMSO at room temperature in good to excellent yields. Copyright Taylor & Francis Group, LLC.
- Shang, Zhenhua
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p. 2927 - 2937
(2007/10/03)
-
- Facile synthesis of symmetric and unsymmetric 1,3,4-oxadiazoles using 2-acyl(or aroyl)pyridazin-3-ones
-
Symmetric and unsymmetric 1,3,4-oxadiazoles were synthesized in situ from hydrazine hydrate and the corresponding 2-acyl-4,5-dichloropyridazin-3-ones as acylating agents in polyphosphoric acid or BF3·OEt2 in excellent yields.
- Park, Yong-Dae,Kim, Jeum-Jong,Chung, Hyun-A,Kweon, Deok-Heon,Cho, Su-Dong,Lee, Sang-Gyeong,Yoon, Yong-Jin
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p. 560 - 564
(2007/10/03)
-
- An expeditious and convenient one pot synthesis of 2,5-disubstituted-1,3,4-oxadiazoles
-
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)
-
- Synthesis of 1,3,4-oxadiazoles using polymer-supported reagents
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The preparation of a novel polystyrene-supported dehydrating agent and its application to the synthesis of 1,3,4-oxadiazoles under thermal and microwave conditions is described. An alternative procedure using tosyl chloride and P-BEMP is also presented.
- Brain,Brunton
-
p. 382 - 384
(2007/10/03)
-
- A mild method for the preparation of 1,3,4-oxadiazoles: Triflic anhydride promoted cyclization of diacylhydrazines
-
Diacylhydrazines undergo cyclization upon treatment with triflic anhydride and pyridine to form the corresponding 1,3,4-oxadiazoles in yields ranging from 70-95%.
- Liras, Spiros,Allen, Martin P.,Segelstein, Barb E.
-
p. 437 - 443
(2007/10/03)
-
- Novel procedure for the synthesis of 1,3,4-oxadiazoles from 1,2- diacylhydrazines using polymer-supported Burgess reagent under microwave conditions
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A novel and efficient means of effecting the cyclodehydration of 1,2- diacylhydrazines to provide 1,3,4-oxadiazoles is reported. Polymer supported Burgess reagent was utilised in combination with single-mode microwave heating.
- Brain, Christopher T.,Paul, Jane M.,Loong, Yvonne,Oakley, Paul J.
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p. 3275 - 3278
(2007/10/03)
-
- 2-Chloro-1,3-dimethylimidazolinium chloride. 2. Its application to the construction of heterocycles through dehydration reactions
-
2-Chloro-1,3-dimethylimidazolinium chloride (DMC) (1) can act as a powerful dehydrating equivalent to DCC (2) under nearly neutral conditions. Its application to the construction of heterocycles through dehydration reactions is described.
- Isobe, Toshio,Ishikawa, Tsutomu
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p. 6989 - 6992
(2007/10/03)
-
- SYNTHESIS AND PROPERTIES OF FURAN DERIVATIVES. 4. SYNTHESIS OF 2,5-DISUBSTITUTED 1,3,4-OXADIAZOLES CONTAINING FURAN FRAGMENTS
-
The condensation of hydrochloride salts of iminoesters of furan acids with hydrazides of carboxylic acids gives 2,5-disubstituted 1,3,4-oxadiazoles containing furan fragments.Such compounds are also formed in the condensation of hydrazides of 5-R-furan-2-carboxylic acids with hydrochloride salts of carboxylic acid iminoesters.The reaction of furan acids with hydrazine dihydrochloride in polyphosphoric acid gave symmetrically disubstituted 1,3,4-oxadiazoles containing furan fragments.
- Karakhanov, R. A.,Kelarev, V. I.,Koshelev, V. N.,Morozova, G. V.,Dibi, Ammar
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p. 208 - 218
(2007/10/03)
-
- A simple one-pot procedure for the synthesis of 1,3,4-oxadiazoles
-
A new method of synthesis of the 2,5-disubstituted 1,3,4-oxadiazoles, which uses the reaction of N-acyl-aldehyde hydrazones with chloramine T is described. The title compounds are obtained in very good yields (85-96%).
- Jedlovska,Lesko
-
p. 1879 - 1885
(2007/10/02)
-
- Fusion of Aroylhydrazines with Acids - A New Synthesis of 2,5-Diaryl-1,3,4-oxadiazoles
-
Aroylhydrazines and aromatic acids when heated together at 240 deg C for 6 hr yield 2,5-diaryl-1,3,4-oxadiazoles (V) in one step.Permanganate oxidation of 1-aroyl-2-arylidenehydrazines is also shown to be a superior method for preparing 1,3,4-oxadiazoles (V).
- Reddy, P. S. N.,Reddy, P. Pratap
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p. 890 - 891
(2007/10/02)
-
- Oxydations d'hydrazones par le bioxyde de plomb: nouvelles syntheses d'oxadiazoles-1,3,4 et de derives de l'amino-4 triazol-1,2,4 one-5
-
Aromatic aldehyde aroylhydrazones when oxidized with lead dioxide, in acetic acid, gave quickly the corresponding 1,3,4-oxadiazoles in good yields.Aromatic aldehyde carbodihydrazones on the other hand, gave derivatives of 4-amino-3-aryl-1,2,4-triazol-5-ones, in dimethylformamide as solvent.To explain these results, some radical mechanisms are proposed.
- Milcent, Rene,Barbier, Geo
-
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- PREPARATION OF 2- AND 2,5-DISUBSTITUTED 1,3,4-OXADIAZOLES FROM TETRAZOLES AND CARBOXYLIC ACIDS
-
The intermediate N-acylated tetrazoles, prepared from 5-substituted tetrazoles, N,N'-dicyclohexylcarbodiimide and carboxylic acids, undergo decomposition to form 2-, or 2,5-disubstituted 1,3,4-oxadiazoles in high yield.
- Povazanec, Frantisek,Kovac, Jaroslav,Svoboda, Jozef
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p. 1299 - 1300
(2007/10/02)
-