- Synthesis and spectral luminescence properties of 2-aryl-5-methyl-1,3,4-oxadiazoles and zinc(ii) 2-(2-hydroxyphenyl)-5-methyl-1,3,4-oxadiazole complex
-
2-Aryl-5-methyl-1,3,4-oxadiazoles were synthesized by reflux of equimolar amounts of acyl hydrazides with triethyl orthoacetate in o-xylene. The obtained oxadiazoles, except for 2-(2-hydroxyphenyl)-5-methyl-1,3,4-oxadiazole, luminesce with a high quantum
- Artyushkina, Yu. M.,Dushenko, G. A.,Mikhailov, I. E.,Minkina, V. I.
-
p. 176 - 178
(2020/04/17)
-
- Electrochemical Synthesis of 2,5-Disubstituted 1,3,4-Oxadiazoles from α-Keto Acids and Acylhydrazines Under Mild Conditions
-
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
-
supporting information
p. 3257 - 3260
(2020/05/25)
-
- TiCl4 mediated facile synthesis of 1,3,4-oxadiazoles and 1,3,4-thiadiazoles
-
An efficient method for the synthesis of 2,5-disubstituted 1,3,4-oxadiazoles and 1,3,4-thiadiazoles has been developed. Various hydrazides or thionyl hydrazides readily react with DMA derivatives in the presence of TiCl4 as a catalyst to afford the desired products. This protocol provides a simple and economical procedure that affords the target products with good yields and wide substrate scope.
- Zhang, Lin,Yu, Yu,Tang, Qiang,Yuan, Jianyong,Ran, Dongzhi,Tian, Binghua,Pan, Tao,Gan, Zongjie
-
p. 423 - 431
(2019/12/27)
-
- UV-Induced 1,3,4-Oxadiazole Formation from 5-Substituted Tetrazoles and Carboxylic Acids in Flow
-
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
-
supporting information
p. 14866 - 14870
(2020/11/11)
-
- Harnessing Autoxidation of Aldehydes: In Situ Iodoarene Catalyzed Synthesis of Substituted 1,3,4-Oxadiazole, in the Presence of Molecular Oxygen
-
Isobutyraldehyde underwent auto-oxidation in the presence of molecular oxygen to generate an acyloxy radical under a "metal-free" environment. They were subsequently exploited in situ to afford hypervalent iodines with p-anisolyl iodide which generated substituted 1,3,4-oxadiazoles in moderate to excellent yields from N′-arylidene acetohydrazides. The reaction strategy tolerated diverse substitution on the hydrazide substrates. Control experiments and literature precedence supported the formation of an in situ iodosylarene complex that facilitates the formation of products.
- Chauhan, Jyoti,Ravva, Mahesh K,Sen, Subhabrata
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p. 6562 - 6565
(2019/09/04)
-
- Batch Versus Flow Lithiation–Substitution of 1,3,4-Oxadiazoles: Exploitation of Unstable Intermediates Using Flow Chemistry
-
1,3,4-Oxadiazoles are a common motif in pharmaceutical chemistry, but few convenient methods for their modification exist. A fast, convenient, high yielding and general α-substitution of 1,3,4-oxadiazoles has been developed using a metalation-electrophilic trapping protocol both in batch and under continuous flow conditions in contradiction to previous reports which suggest that α-metalation of this ring system results in ring fragmentation. In batch, lithiation is accomplished at an industrially convenient temperature, ?30 °C, with subsequent trapping giving isolated yields of up to 91 %. Under continuous flow conditions, metalation is carried out at room temperature, and subsequent in flow electrophilic trapping gave up to quantitative isolated yields. Notably, lithiation in batch at room temperature results only in ring fragmentation and we propose that the superior mixing in flow allows interception and exploitation of an unstable intermediate before decomposition can occur.
- Wong, Jeff Y. F.,Tobin, John M.,Vilela, Filipe,Barker, Graeme
-
supporting information
p. 12439 - 12445
(2019/09/06)
-
- Electrophilic activation of nitroalkanes in efficient synthesis of 1,3,4-oxadiazoles
-
A novel methodology for general and chemoselective preparation of non-symmetric 1,3,4-oxadiazoles is developed. This unusual reaction proceeds via polyphosphoric acid-assisted activation of nitroalkanes towards nucleophilic attack with acylhydrazides.
- Aksenov, Alexander V.,Khamraev, Vladislav,Aksenov, Nicolai A.,Kirilov, Nikita K.,Domenyuk, Dmitriy A.,Zelensky, Vladimir A.,Rubin, Michael
-
p. 6636 - 6642
(2019/03/14)
-
- Synthesis of 2,5-disubstituted 1,3,4-oxadiazoles by visible-light-mediated decarboxylation–cyclization of hydrazides and diketones
-
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)
-
- Ligand-free Cu(ii)-mediated aerobic oxidations of aldehyde hydrazones leading to N,N′-diacylhydrazines and 1,3,4-oxadiazoles
-
A Cu(ii)-mediated synthesis of N,N′-diacylhydrazines and 1,3,4-oxadiazoles from aldehyde hydrazones has been developed. This is the first time that the synthesis of N,N′-diacylhydrazines and 1,3,4-oxadiazoles using N,N-dimethylamides as the acylation reagent and O2 in air as the oxidation reagent is reported. These reactions offered several advantages including simple workups, ligand-free inexpensive metal salts as mediators, high yields, and wide scope of substrates.
- Liu, Lei,Feng, Suliu
-
supporting information
p. 2585 - 2592
(2017/04/03)
-
- METHOD FOR PREPAREING 1,3,4-OXADIAZOL UNDER SOLVENT-FREE CONDITION
-
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; 0232-0233; 0397-0398
(2017/02/24)
-
- 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
-
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
-
supporting information
p. 4616 - 4619
(2016/09/23)
-
- Palladium-catalyzed one-pot synthesis of diazoles via tert-butyl isocyanide insertion
-
An efficient one-pot palladium-catalyzed reaction for the synthesis of diazoles from readily available hydrazides and aryl halide via isocyanide insertion/cyclization sequence has been developed. This methodology efficiently constructs diazoles in good to excellent yields with the advantages of wide functional group tolerance and operational simplicity.
- Fan, Xiang-Yuan,Jiang, Xiao,Zhang, Ying,Chen, Zhen-Bang,Zhu, Yong-Ming
-
p. 10402 - 10408
(2015/10/28)
-
- Metal-Free Synthesis of 1,3,4-Oxadiazoles from N′-(Arylmethyl)hydrazides or 1-(Arylmethyl)-2-(arylmethylene)hydrazines
-
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
-
p. 1032 - 1040
(2015/03/30)
-
- Iodine-catalysed oxidative cyclisation of acylhydrazones to 2,5-substituted 1,3,4-oxadiazoles
-
An environmentally benign synthesis of 2,5-disubstituted 1,3,4-oxadiazoles has been developed starting from N-aroylhydrazones and N-acetylhydrazones at room or ambient temperature using a catalytic quantity of iodine in the presence of an aqueous hydrogen peroxide oxidant.
- Majji, Ganesh,Rout, Saroj Kumar,Guin, Srimanta,Gogoi, Anupal,Patel, Bhisma K.
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p. 5357 - 5362
(2014/01/23)
-
- Efficient synthesis of 1,3,4-oxadiazoles promoted by NH4Cl
-
An efficient and inexpensive approach to the synthesis of 2-substituted and 2,5-disubstituted 1,3,4-oxadiazoles from arylhydrazides and orthoesters is reported using catalytic NH4Cl. The conditions are mild, and thus, compatible with a variety of functional groups. The optimized reaction is performed using 30 mol % of NH4Cl in 100% EtOH and is generally complete within 1 h for non-aromatic orthoesters and 2-10 h for aromatic orthoesters. The reaction permits both electron-releasing and electron-withdrawing groups on the arylhydrazide substrate. Most products are formed in high yields and require only minimal purification. Compared with earlier reports, the current reactions proceed in shorter time and require less of the orthoester.
- Gnanasekaran, Krishna Kumar,Nammalwar, Baskar,Murie, Maeghan,Bunce, Richard A.
-
supporting information
p. 6776 - 6778
(2015/01/09)
-
- One-pot synthesis of 2,5-disubstituted-1,3,4-oxadiazoles based on the reaction of N,N-dimethyl amides with acid hydrazides
-
Convenient and efficient one pot method for the synthesis of 2,5-disubstituted-1,3,4-oxadiazoles based on the reaction of N,N-dimethyl amides with acid hydrazides has been developed. The methodology is applied to a wide range of difference aryl hydrazide and difference N,N-dimethyl amides to 2,5-disubstituted-1,3,4-oxadiazoles yield the in good to excellent yields. It will be possible wide useful application in synthesis. Synopsis Convenient and efficient one pot method for the synthesis of 2,5-disubstituted-1,3,4- oxadiazoles based on the reaction of N,N-dimethyl amides with acid hydrazides has been developed. The methodology is applied to a wide range of difference aryl hydrazide and difference N,N-dimethyl amides to 2,5-disubstituted- 1,3,4-oxadiazoles yield the in good to excellent yields. It will be possible wide useful application in synthesis. Copyright
- Li, Qiang,Tao, Yi,Xu, Dongfang,Zhang, Haobing,Duan, Liping
-
p. 665 - 670
(2014/06/24)
-
- Efficient oxidative cyclisation of acid hydrazides to 2,5-disubstituted 1,3,4-oxadiazoles catalysed by Bu4NI with t-BuOOH as oxidant
-
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
-
p. 506 - 510
(2013/09/12)
-
- One-pot, three component synthesis of 2,5-disubstituted 1,3,4-oxadiazoles catalyzed by heteropolyacid
-
H6[PMo9V3O40] was used as an efficient catalyst for the preparation of 1-aroyl-2-arylidene hydrazines. 2,5-Disubstituted 1,3,4-oxadiazoles have been synthesized by oxidation of 1-aroyl-2-arylidene hydrazines with CrO3 in excellent yields.
- Heravi, Majid M.,Zadsirjan, Vahideh,Bakhtiari, Khadijeh,Bamoharram, Fatemeh F.
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p. 259 - 263
(2013/03/29)
-
- Synthesis of 1,3,4-oxadiazoles from 1,2-diacylhydrazines using [Et 2NSF2]BF4 as a practical cyclodehydration agent
-
The preparation of 1,3,4-oxadiazoles from 1,2-diacylhydrazines using XtalFluor-E ([Et2NSF2]BF4) as cyclodehydration reagent is described. Various functionalized 1,3,4-oxadiazoles were synthesized and it was found that the use of acetic acid as an additive generally improved the yields.
- Pouliot, Marie-France,Angers, Laetitia,Hamel, Jean-Denys,Paquin, Jean-Francois
-
p. 988 - 993
(2012/04/10)
-
- High-temperature continuous flow synthesis of 1,3,4-oxadiazoles via N-acylation of 5-substituted tetrazoles
-
Applying continuous flow processing in a high-temperature/high-pressure regime (200-220 °C, 11-14 bar) 2,5-disubstituted-1,3,4-oxadiazoles are prepared in high yields within 5-10 min residence time by treatment of 5-substituted-1H-tetrazoles with anhydrides or acid chlorides as electrophiles (Huisgen reaction).
- Reichart, Benedikt,Kappe, C. Oliver
-
supporting information; experimental part
p. 952 - 955
(2012/03/11)
-
- Tetrazoles: LIII. Microwave-activated acylation of 5-substituted tetrazoles
-
The acylation of 5-aryl(hetaryl)tetrazoles with acetic and benzoic anhydrides under microwave irradiation gave the corresponding 2-substituted 5-methyl-and 5-phenyl-1,3,4-oxadiazoles in high yields. The use of microwave activation reduces the reaction temperature by 30-40°C and shortens the reaction time by a factor of 5 to 7.
- Efimova,Artamonova,Koldobskii
-
experimental part
p. 1345 - 1347
(2009/09/06)
-
- Silica sulfuric acid: An efficient and versatile acidic catalyst for the rapid and ecofriendly synthesis of 1,3,4-oxadiazoles at ambient temperature
-
A rapid and green synthesis of 2,5-disubstituted 1,3,4-oxadiazoles is reported. The title compounds were prepared by the reaction of different acyl hydrazides and orthoesters in the presence of silica sulfuric acid under solvent-free conditions. In this new process, reactions were run at ambient temperature and completed in a short period of time with high yields. Copyright Taylor & Francis Group, LLC.
- Dabiri, Minoo,Salehi, Peyman,Baghbanzadeh, Mostafa,Zolfigol, Mohammad Ali,Bahramnejad, Mahboobeh
-
p. 1201 - 1209
(2008/02/01)
-
- Alum (KAl(SO4)2 ? 12H2O): An efficient and inexpensive catalyst for the one-pot synthesis of 1,3,4-oxadiazoles under solvent-free conditions
-
Alum (KAl(SO4)2 ? 12H2O) catalyzed the efficient synthesis of mono- and disubstituted 1,3,4-oxadiazoles by the condensation of acyl hydrazides with orthoesters under solvent-free conditions at 100°C. This methodology offers significant improvements for the synthesis of oxadiazoles with regard to the yield of products, simplicity in operation, inexpensive reagents, and green aspects by avoiding toxic catalysts and solvents.
- Dabiri, Minoo,Salehi, Peyman,Baghbanzadeh, Mostafa,Bahramnejad, Mahboobeh
-
p. 1253 - 1255
(2008/03/28)
-
- Photochemistry of sulfilimine-based nitrene precursors: Generation of both singlet and triplet benzoylnitrene
-
(Graph Presented) Photolysis of N-benzoyl-S,S-diphenylsulfilimine or N-benzoyl dibenzothiophene sulfilimine produces PhNCO and also benzoylnitrene. Direct observation of the triplet nitrene, energetic differences between the singlet and triplet state of the nitrene, and oxygen quenching experiments suggest that the triplet nitrene derives from the triplet excited state of the sulfilimine precursors, rather than through equilibration of nearby singlet and triplet states of the nitrene itself. In acetonitrile, the formation of an ylide, followed by cyclization to the corresponding oxadiazole, is the predominant nitrene chemistry, occurring on the time scale of a few microseconds and few tens of microseconds, respectively. Trapping experiments with substrates such as cis-4-octene suggest that reactivity of the nitrene is mainly through the singlet channel, despite a fairly small energy gap between the singlet ground state and the triplet.
- Desikan, Vasumathi,Liu, Yonglin,Toscano, John P.,Jenks, William S.
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p. 6848 - 6859
(2008/02/11)
-
- Oxidative cyclization of aromatic aldehyde n-acylhydrazones by bis(trifluoroacetoxy)iodobenzene
-
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
-
p. 2927 - 2937
(2007/10/03)
-
- P2-P3 conformationally constrained ketoamide-based inhibitors of cathepsin K
-
An orally bioavailable series of ketoamide-based cathepsin K inhibitors with good pharmacokinetic properties has been identified. Starting from a potent inhibitor endowed with poor drug properties, conformational constraint of the P2-P3 linker and modifications to P1′ elements led to an enhancement in potency, solubility, clearance, and bioavailability. These optimized inhibitors attenuated bone resorption in a rat TPTX hypocalcemic bone resorption model.
- Barrett, David G.,Boncek, Virginia M.,Catalano, John G.,Deaton, David N.,Hassell, Anne M.,Jurgensen, Cynthia H.,Long, Stacey T.,McFadyen, Robert B.,Miller, Aaron B.,Miller, Larry R.,Payne, J. Alan,Ray, John A.,Samano, Vicente,Shewchuk, Lisa M.,Tavares, Francis X.,Wells-Knecht, Kevin J.,Willard Jr., Derril H.,Wright, Lois L.,Zhou, Hui-Qiang Q.
-
p. 3540 - 3546
(2007/10/03)
-
- Heterocyclic rearrangements in constrained media. A zeolite-directed photorearrangement of 1,2,4-oxadiazoles
-
(Chemical Equation Presented) The first intrazeolite-photoinduced rearrangement of a five-membered heterocycle is reported. A completely different behavior compared to solution irradiations has been observed. The zeolite's role in directing the photoreaction of 3-phenyl-1,2,4-oxadiazoles toward the formation of the corresponding 1,3,4-oxadiazoles in a ring contraction-ring expansion route is discussed.
- Pace, Andrea,Buscemi, Silvestre,Vivona, Nicolo
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p. 2322 - 2324
(2007/10/03)
-
- Microwave assisted syntheses of 2,5-disubstituted 1,3,4-oxadiazoles
-
2,5-Di-substituted 1,3,4-oxadiazoles have been synthesized from the oxidation of 1-aroyl-2-arylidene hydrazines with potassium permanganate on the surface of solid mineral support as well as in the mixture of acetone and water under microwave irradiation. 2,5-Disubstituted 1,3,4-oxadiazoles have been synthesized by oxidation of 1-aroyl-2-arylidene hydrazines with potassium permanganate on the surface of a solid mineral support as well as in mixtures of acetone and water under microwave irradiation.
- Rostamizadeh, Shahnaz,Housaini, S.A. Ghasem
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p. 8753 - 8756
(2007/10/03)
-
- A new approach to the one-pot synthesis of 5-substituted 2-methyl-1,3,4-oxadiazoles from N-tributylstannyltetrazoles
-
A new approach to the synthesis of 5-substituted 2-methyl-1,3,4-oxadiazoles was developed.
- Semenov, B. B.,Smushkevich, Yu. I.
-
p. 357 - 358
(2007/10/03)
-
- Synthesis of 1,3,4-oxadiazoles using polymer-supported reagents
-
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)
-
- The application of cross-linked poly[styrene(iodoso diacetate)] to the synthesis of 1,3,4-oxadiazoles
-
The 2% cross-linked poly[styrene(iodosodiacetate)] has been synthesized, and has been applied effectively to the synthesis of 1,3,4-oxadiazole derivatives, and regenerated and reused for the same reaction.
- Huang, Xian,Zhu, Qing
-
p. 300 - 301
(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)
-
- A new synthesis of 1,3,4-oxadiazoles. Cyclization of N,N'- diacylhydrazines catalyzed by palladium(0)
-
Several 1,3,4-oxadiazoles were synthetized by cyclization of N,N'- diacylhydrazines catalyzed by palladium(0). Water formed during the reaction is responsible for the hydrolysis of the products. To avoid it, we introduced benzoic anhydride into the medium and obtained an increased yield of oxadiazoles.
- Lutun, Stephane,Hasiak, Bruno,Couturier, Daniel
-
p. 111 - 116
(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
-
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)
-
- Synthesis of 1,3,4-Oxadiazoles from Carboxylic Hydrazides and of 1,2-Oxazin-6-ones from α-(Hydroxyimino)carboxylic Esters with Keteneylidene Triphenylphosphorane
-
In a one-pot procedure 1,3,4-oxadiazoles 8 are prepared from carboxylic hydrazides 2 and keteneylidene triphenylphosphorane 1 via an untypical intermolecular Wittig olefination of a carbamate type carbonyl group. Under similar conditions, reaction of 1 an
- L?ffler, Jonas,Schobert, Rainer
-
p. 283 - 284
(2007/10/03)
-
- An efficient synthesis of 1,3,4-oxadiazoles from N,N′-diacylhydrazines using Ph3P·Br2, Ph3P·CCl4 or Ph3P·CBr4 adducts as condensing agents
-
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
-
-
- Synthesis and spectral properties of 2-methyl-5-aryl-1,3,4-oxadiazoles
-
By heterocyclization of 1-acyl-2-aroylhydrazines under the influence of strong dehydrating substances, a series of 2-methyl-5-aryl-1,3,4-oxadiazoles has been synthesized and their UV, IR, and PMR spectra have been investigated. Through analysis of data on
- Popova,Krasovitskii,Pivnenko,Surov
-
p. 712 - 717
(2007/10/03)
-
- The photochemistry of acyl azides - IX. Direct and sensitized photolytic generation of acylnitrenes for cycloaddition reactions
-
Contrary to ethoxycarbonylnitrene, selective reactions - including cycloadditions - can be carried out with benzoylnitrene. This study analyzes the sequence of reactivity of various bond types with respect to benzoylnitrene, which was generated by three different routes: direct photolysis of benzoyl azide, sensitization of azide decomposition via energy transfer, and photoinduced electron transfer. In all cases the same cycloadducts 23, 24, and 30 were obtained. Carbonyl activity determines the reactivity of unsaturated ketones and aldehydes with respect to benzoylnitrene.
- Clauss, Kai-Uwe,Buck, Karin,Abraham, Werner
-
p. 7181 - 7192
(2007/10/02)
-
- SYNTHESIS OF 2,5-DISUBSTITUTED 1,3,4-OXADIAZOLES FROM TRICHLOROMETHYLARENES AND ACYLHYDRAZINES
-
A preparative synthesis of 2,5-disubtituted 1,3,4-oxadiazoles by the reaction of trichloromethylarenes with hydrazides of carboxylic acids of the aliphatic, aromatic and heteroaromatic series in methanol or ethanol in the presence of pyridine was developed.
- Poddubnyi, I. S.,Belen'skii, L. I.,Krayushkin, M. M.
-
p. 602 - 607
(2007/10/02)
-
- Synthesis of Unsymmetrically Substituted 4H-1,2,4-Triazoles
-
A general method was developed for the synthesis of unsymmetrically 3,5-disubstituted 4H-1,2,4-triazoles (Ph, H or Ph, CH3) with allyl or benzyl groups in the 4-ring position.The reaction of the corresponding 3,5-disubstituted 1,3,4-oxadiazoles with allyl
- Carlsen, Per H. J.,Joergensen, Kare B.
-
p. 805 - 808
(2007/10/02)
-
- TETRAZOLES IN THE SYNTHESES OF 1,3,4-OXADIAZOLES
-
Various variants of cleavage of tetrazoles to form 1,3,4-oxadiazoles are examined.The mechanisms and synthetic potentialities of these reactions are discussed.
- Koldobskii, G. I.,Ivanova, S. E.
-
p. 1512 - 1517
(2007/10/03)
-
- Hypervalent Iodine Oxidation of N-Acylhydrazones and N-Phenylsemicarbazone: An Efficient Method for the Synthesis of Derivatives of 1,3,4-Oxadiazoles and Δ3-1,3,4-Oxadiazolines
-
The oxidation of ketone N-acylhydrazones 1 by phenyliodine(III) diacetate (PIDA) in alcohol gave 2-alkoxy-Δ3-1,3,4-oxadiazolines 4 in excellent yields, while the oxidative cyclization of aldehyde N-acylhydrazone 2 by PIDA in methanolic sodium acetate gave 2,5-disubstituted 1,3,4-oxadiazoles in good yields.The oxidation of acetone 4-phenylsemicarbazone afforded 2-(N-phenylimino)-Δ3-1,3,4-oxadiazoline in excellent yield.
- Yang, Rui-Yang,Dai, Li-Xin
-
p. 3381 - 3383
(2007/10/02)
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- Electrooxidative Cyclization of N-Acylhydrazones of Aldehydes and Ketones to Δ3-1,3,4-Oxadiazolines and 1,3,4-Oxadiazoles
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The electrolytic oxidation of ketone N-acylhydrazones (1) in methanolic sodium acetate induced their intramolecular cyclization to the corresponding 2-methoxy-Δ3-1,3,4-oxadiazolines 3.The thermal stability of a given oxadiazoline and what products were formed by its thermal decomposition was found to depend on the natures of the substituents at C-2.Thus, 2-methoxy-2-phenyloxadiazolines preferentially yielded oxiranes 5, whereas 2-alkyl-2-methoxyoxadiazolines preferentially gave enol ethers 6. 2,2-Dimethoxyoxadiazolines decomposed to the parent ketones and many unidentified products.The electrolytic oxidation of aldehyde N-acylhydrazones 2 gave 2,5-disubstituted 1,3,4-oxadiazoles 4.The oxidative cyclization of the N-benzoylhydrazones of aliphatic aldehydes gave especially high yields of the corresponding heterocycles.
- Chiba, Toshiro,Okimoto, Mitsuhiro
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p. 1375 - 1379
(2007/10/02)
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- TETRAZOLES. XXX. ACYLATION OF 5-SUBSTITUTED TETRAZOLES
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The acylation of 5-substituted tetrazoles with carboxylic acid chlorides and anhydrides gives rise to 2,5-disubstituted 1,3,4-oxadiazoles in high yields.The reaction goes without the addition of organic bases at 100-105 deg C.The acylation of 5-substituted tetrazoles in a two-phase organic solvent-water system in presence of tetrabutylammonium bromide yields N-acyltetrazoles, which are converted into 2,5-disubstituted 1,3,4-oxadiazoles on thermolysis.
- Myznikov, Yu. E.,Koldobskii, G. I.,Ostrovskii, B. A.,Poplavskii, V. S.
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p. 1125 - 1128
(2007/10/02)
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- Dihydropyridine anti-allergic and anti-inflammatory agents
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4-Aryl-3-alkoxycarbonyl-6-methyl-5-carbamyl-2-triazolylalkoxymethyl-1,4-dihyd ropyridines as anti-allergic and anti-inflammatory agents.
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- DISILYLATED COMPOUNDS AS PRECURSORS OF HETEROCYCLES: A NEW AND EASY OXADIAZOLE SYNTHESIS
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Silyl diacylhydrazines have been synthesized.When they are treated with a slight amount of a variety of catalyst (nucleophiles, F-, true or Lewis acids, Pd, Pt...), 1,3,4-oxadiazoles are obtained.This cyclization can be performed in one step by
- Rigo, Benoit,Fasseur, Dominique,Cauliez, Pascal,Couturier, Daniel
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p. 2321 - 2336
(2007/10/02)
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- ACID CATALYZED CYCLIZATION OF BIS SILYL DIACYLHYDRAZINES : A NEW 1,3,4-OXADIAZOLE SYNTHESIS
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Diacylhydrazines are converted in good yields into 1,3,4-oxadiazoles with dichlorodimethylsilane and trifluoromethane sulfonic acid.
- Rigo, Benoit,Cauliez, Pascal
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p. 1247 - 1252
(2007/10/02)
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- REACTION OF HEXAMETHYLDISILAZANE WITH DIACYLHYDRAZINES: AN EASY 1,3,4-OXADIAZOLE SYNTHESIS.
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The reaction of diacylhydrazines with hexamethyldisilazane in the presence of tetrabutylammonium fluoride as catalyst results in cyclisation to give 1,3,4-oxadiazoles in good yield.
- Rigo, Benoit,Cauliez, Pascal,Fasseur, Dominique,Couturier, Daniel
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p. 1665 - 1670
(2007/10/02)
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