- Neuroprotective evaluation of novel substituted 1,3,4-oxadiazole and aroylhydrazone derivatives
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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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- Design, synthesis, modelling studies and biological evaluation of 1,3,4-oxadiazole derivatives as potent anticancer agents targeting thymidine phosphorylase enzyme
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A series of novel 1,3,4-oxadiazole derivatives with substituted phenyl ring were designed and synthesized with an objective of discovering newer anti-cancer agents targeting thymidine phosphorylase enzyme (TP). The 1,3,4-oxadiazole derivatives were synthesized by simple and convenient methods in the lab. Chemical structure of the all the synthesized compounds were characterized by IR, 1H NMR and mass spectral methods and evaluated for cytotoxicity by MTT method against two breast cancer cell lines (MCF-7 and MDA-MB-231). Further, results of TP assay identified that 1,3,4-oxadiazole molecules displayed anti-cancer activity partially by inhibition of phosphorylation of thymidine. The TP assay identified SB8 and SB9 as potential inhibitors with anti-cancer activity against both the cell lines. The molecular docking studies recognized the orientation and binding interaction of molecule at the active site amino acid residues of TP (PDB: 1UOU). Acute toxicity studies of compound SB8 at the dose of 5000 mg/kg has identified no signs of clinical toxicity was observed. The SARs study of synthesized derivatives revealed that the substitution of phenyl ring with electron withdrawing group at ortho position showed significant TP inhibitory activity compared to para substitution. The experimental data suggests that 1,3,4-oxadiazole with substituted phenyl can be taken as a lead for the design of efficient TP inhibitors and active compounds which can be taken up for further studies.
- Bajaj, Shalini,Kumar, Maushmi S.,Tinwala, Hussain,YC, Mayur
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- The preparation, characterization and catalytic activity of Ni NPs supported on porous alginate-g-poly(p-styrene sulfonamide-co-acrylamide)
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Herein, we report the synthesis of nickel nanoparticles under mild conditions using porous alginate-g-poly(p-styrene sulfonamide-co-acrylamide) as a protecting/stabilizing agent and sodium borohydride as a reducing agent. The porous cross-linked polymeric support was preparedviacombining the use of sol-gel, nanocasting, and crosslinking techniques, in which thep-styrene sulfonamide monomer (PSSA) andN,N′-methylene-bis (acrylamide) (MBA) cross-linker underwent copolymerization on the surface of sodium alginate in the presence of a SiO2nanoparticle (NP) template (Alg-PSSA-co-ACA). The prepared catalyst (Alg-PSSA-co-ACA@Ni) showed high catalytic activity for the one-step synthesis of 1,3,4-oxadiazoles from the reaction of hydrazides and aryl iodides through isocyanide insertion/cyclization.
- Alavinia, Sedigheh,Ghorbani-Vaghei, Ramin
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p. 29728 - 29740
(2021/10/06)
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- COMPOUND AND ORGANIC LIGHT EMITTING DEVICE COMPRISING THE SAME
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The present specification provides a compound represented by chemical formula 1 and an organic light emitting device including the same. The compound may improve lifespan characteristics of the organic light emitting device.
- -
-
Paragraph 0274-0277
(2021/01/29)
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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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- 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)
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- Photocatalyzed facile synthesis of 2,5-diaryl 1,3,4-oxadiazoles with polyaniline-?g-C3N4-TiO2 composite under visible light
-
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
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supporting information
p. 1489 - 1492
(2018/03/13)
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- Microwave-mediated Green synthesis of oxadiazole derivatives against inflammatory disease
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A rapid and efficient microwave-mediated Green synthesis of oxadiazole derivatives (2a-e) is described based on reaction between benzohydrazide and various substituted benzoic acids. The use of microwave irradiation to carry out chemical reactions provide
- Sahoo, Biswa Mohan,Panda, Jnyanaranjan,Banik, Bimal Krishna,Sahoo, Binayani
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p. 1307 - 1310
(2020/06/27)
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- 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
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supporting information
p. 767 - 770
(2018/02/07)
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- Ligand-free Cu(ii)-mediated aerobic oxidations of aldehyde hydrazones leading to N,N′-diacylhydrazines and 1,3,4-oxadiazoles
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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)
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- Three-component synthesis method of oxadiazole compound
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The invention relates to a synthesis method of an oxadiazole compound shown in formula (III). The method comprises steps as follows: a compound shown in formula (1), a compound shown in formula (II) and an amine source compound react at 80-100 DEG C for 6-10 h in the presence of an organic solvent, a catalyst, base and an additive, after-treatment is performed after the reaction ends, and the compound shown in formula (III) is obtained, wherein R1 is C1-C6 alkyl groups, phenyl groups or phenyl groups substituted with substitute groups, substitute groups are C1-C6 alkyl groups, C1-C6 alkoxy groups or halogen, and R2 is H, C1-C6 alkyl groups, C1-C6 alkoxy groups or halogen. A specific three-component reaction system is adopted in the method, comprehensive synergism of a specific catalytic system is combined, so that a target product can be obtained at the high yield, and the method has good application prospect and value.
- -
-
Paragraph 0045-0048
(2017/05/12)
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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
-
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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- 2,5-Diaryloxadiazoles and their precursors as novel inhibitors of cathepsins B, H and L
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High levels of cathepsins indicated in various pathological conditions like arthritis, cancer progressions, and atherosclerosis explains the need to explore potential inhibitors of these proteases which can be of great therapeutic significance. We, in the present work, report the synthesis of some 2,5-diaryloxadiazoles from N-subsitutedbenzylidenebenzohydrazides. The synthesized compounds were screened for their inhibitory potential on cathepsins B, H and L. Structure Activity Relationship studies show that 2,5-diaryloxadiazoles were less inhibitory than their precursors. 1i and 2k have been found to be most inhibitory to cathepsins B and L. Their Ki values have been calculated as 11.38 × 10-8 M and 66.4 × 10-8 M for cathepsin B and 4.2 × 10-9 M and 47.31 × 10-9 M for cathepsin L, respectively. However, cathepsin H activity was maximally inhibited by compounds, 1e and 2c with Ki values of 4.4 × 10-7 M and 5.6 × 10-7 M, respectively. Enzyme kinetic studies suggest that these compounds are competitive inhibitors to the enzymes. The results have been compared with docking results obtained using iGemDock.
- Garg, Shweta,Raghav, Neera
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- Ligand-free copper(0) catalyzed direct C-H arylation of 1,2,4-triazoles and 1,3,4-oxadiazoles with aryl iodides in PEG-400
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A ligand-free copper catalyzed approach has been developed to the synthesis of 3,4,5-triaryl-1,2,4-triazoles and 2,5-diaryl-1,3,4-oxadiazoles by the direct arylation of corresponding 3,4-diaryl-1,2,4-triazoles and 2-aryl-1,3,4-oxadiazoles with aryl iodides using PEG-400 as reaction medium. The procedure is experimentally simple and free from addition of external chelating ligands or co-catalysts.
- Tadikonda, Ramu,Nakka, Mangarao,Rayavarapu, Srinuvasarao,Kalidindi, Siva Prasada Kumar,Vidavalur, Siddaiah
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supporting information
p. 690 - 692
(2015/01/30)
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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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- Palladium-catalyzed one-pot synthesis of diazoles via tert-butyl isocyanide insertion
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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
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p. 10402 - 10408
(2015/10/28)
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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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- One-Pot Synthesis of 2,5-Diaryl 1,3,4-Oxadiazoles via Di-tert-butyl Peroxide Promoted N-Acylation of Aryl Tetrazoles with Aldehydes
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A metal- and base-free protocol for one-pot synthesis of 2,5-diaryl 1,3,4-oxadiazoles via a radical-promoted cross-dehydrogenative coupling strategy was developed. This reaction involved the N-acylation of aryl tetrazoles with aryl aldehydes, followed by thermal rearrangement. A wide range of aryl tetrazoles and aryl aldehydes survived the reaction conditions to deliver the corresponding products in moderate to good yields. (Chemical Equation Presented).
- Wang, Liang,Cao, Jing,Chen, Qun,He, Mingyang
-
supporting information
p. 4743 - 4748
(2015/05/13)
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- In situ generated cetyltrimethylammonium bisulphate in choline chloride-urea deep eutectic solvent: A novel catalytic system for one pot synthesis of 1,3,4-oxadiazole
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Cetyltrimethylammonium bisulphate ([CTA]HSO4) catalysed one pot synthesis of 2,5-disubstituted-1,3,4-oxadiazoles from carboxylic acid and acid hydrazide in biodegradable deep eutectic solvent is investigated. [CTA]HSO 4 is generated in situ from cetyltrimethylammonium peroxodisulphate. Cyclization of diacylhydrazide using [CTA]HSO4 gives best alternative to traditional dehydration agents. Its remarkable features include a milder procedure, simplicity in workup and purification, good to excellent yields of products, use of inexpensive, recyclable reagents, and eco-friendly aspects by avoiding toxic catalysts/reagents and solvents. Graphical Abstract: [Figure not available: see fulltext.].
- More, Priyanka Anant,Gadilohar, Balu Laxman,Shankarling, Ganapati Subray
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p. 1393 - 1398
(2014/08/18)
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- C-H arylation of azaheterocycles: A direct ligand-free and Cu-catalyzed approach using diaryliodonium salts
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An efficient and high yielding Cu-catalyzed direct C-H arylation of azaheterocycles including oxadiazoles, thiadiazoles, benzoxazoles and benzothiazoles has been achieved by employing easily accessible diaryliodonium salts. the Partner Organisations 2014.
- Kumar, Dalip,Pilania, Meenakshi,Arun,Pooniya, Savita
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supporting information
p. 6340 - 6344
(2014/08/18)
-
- Efficient synthesis of 1,3,4-oxadiazoles promoted by NH4Cl
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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.
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supporting information
p. 6776 - 6778
(2015/01/09)
-
- Iodine-catalysed oxidative cyclisation of acylhydrazones to 2,5-substituted 1,3,4-oxadiazoles
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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)
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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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- One-pot, three component synthesis of 2,5-disubstituted 1,3,4-oxadiazoles catalyzed by heteropolyacid
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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)
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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
-
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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- 2,4,6-Tris[(4-dichloroiodo)phenoxy)]-1,3,5-triazine as a new recyclable hypervalent iodine(III) reagent for chlorination and oxidation reactions
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The synthesis of 2,4,6-tris[(4-dichloroiodo)phenoxy)]-1,3,5-triazine, as a new recyclable nonpolymeric analogue of (dichloroiodo)benzene, is achieved in two steps using 2,4,6-trichloro-1,3,5-triazine and 4-iodophenol. The application of 2,4,6-tris[(4-dichloroiodo)phenoxy)]-1,3,5-triazine for the chlorination reaction of various activated arenes, olefin, and 1,3-diketone is demonstrated. The reagent 2,4,6-tris[(4-dichloroiodo)phenoxy)]-1,3,5-triazine can be applied also for the oxidative synthesis of 1,3,4-oxadiazoles and 1,2,4-thiadiazoles under mild conditions in excellent yields. The recyclability of the 2,4,6-tris[(4-dichloroiodo)phenoxy)]-1,3,5-triazine was possible owing to the facile recovery and reuse of the coproduced 2,4,6-tris(4-iodophenoxy)-1,3,5- triazine from the reaction mixture due to its practical insolubility in methanol. Georg Thieme Verlag Stuttgart, New York.
- Thorat, Prerana B.,Bhong, Bhagyashree Y.,Karade, Nandkishor Y.
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supporting information
p. 2061 - 2066
(2013/10/21)
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- Synthesis of 1,3,4-oxadiazoles from 1,2-diacylhydrazines using [Et 2NSF2]BF4 as a practical cyclodehydration agent
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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
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experimental part
p. 988 - 993
(2012/04/10)
-
- 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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- 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.
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p. 5976 - 5979
(2012/01/02)
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- 17O NMR studies of substituted 1,3,4-oxadiazoles
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Three series of substituted 1,3,4-oxadiazoles were studied by 17O NMR spectroscopy. Chemical shifts values were correlated with empirical Hammett parameters as well as calculated bond lengths and chemical shielding values.
- Gierczyk, Blazej,Zalas, MacIej,Kazmierczak, Marcin,Grajewski, Jakub,Pankiewicz, Radoslaw,Wyrzykiewicz, Bozena
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p. 648 - 654
(2012/01/06)
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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)
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- N-chlorosuccinimide/1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-mediated synthesis of 2,5-disubstituted 1,3,4-oxadiazoles
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A mixture of N-chlorosuccinimide and 1,8-diazabicyclo[5.4.0]undec-7-ene oxidatively cyclizes structurally diverse acyl hydrazone, thereby providing an efficient and convenient method for the synthesis of various 2,5-disubstituted 1,3,4-oxadiazoles. The salient features of this method are mild reaction conditions, short reaction time, excellent yields, and simple workup procedure. Copyright
- Pardeshi, Santosh P.,Patil, Sachin S.,Bobade, Vivek D.
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experimental part
p. 1601 - 1606
(2010/06/20)
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- Mild and convenient one-pot synthesis of 1,3,4-oxadiazoles
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A mild, general, convenient, and efficient one-pot synthesis of 2-phenyl-5-substituted-1,3,4-oxadiazoles is described. Both (hetero)aryl and alkyl carboxylic acids were efficiently condensed with benzohydrazide in the presence of TBTU to give diacylhydrazine intermediates. The latter underwent a smooth TsCl-mediated cyclodehydration reaction to afford 2-phenyl-5-substituted- 1,3,4-oxadiazoles in good to very good yields.
- Stabile, Paolo,Lamonica, Alessandro,Ribecai, Arianna,Castoldi, Damiano,Guercio, Giuseppe,Curcuruto, Ornella
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supporting information; experimental part
p. 4801 - 4805
(2010/10/02)
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- Copper-mediated direct arylation of 1,3,4-oxadiazoles and 1,2,4-triazoles with aryl iodides
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The copper-mediated direct arylation of 1,3,4-oxadiazoles and 1,2,4-triazoles with aryl iodides proceeds efficiently in the presence of suitable ligands and bases. This method allows the installation of a variety of aryl moieties bearing a functional group such as ketone, ester, or nitrile so as to enable the facile construction of various functionalized oxadiazole and triazole core π systems.
- Kawano, Tsuyoshi,Yoshizumi, Tomoki,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information; experimental part
p. 3072 - 3075
(2009/12/06)
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- Convenient preparation of unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles promoted by Dess-Martin reagent
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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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- 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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- Synthesis, oxidation and dehydrogenation of cyclic N,O- and N,S-acetals. Part III. [1,2] Transformation of N,O-acetals: 3-Acyl-1,3,4-oxadiazolines
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(Chemical Equation Presented) Various aldehyde and ketone acylhydrazones are synthesized and, under acylating conditions, cyclized into 3-acyl-1,3,4-oxadiazolines. The scope and limitations of these cyclizations and the possible side reactions (e.g. formation of the open-chain N,O-acylhydrazinocarbinols) are dissected. For the first time, simple, convenient and efficient dehydrogenations of 3-acyl-1,3,4-oxadiazolines to oxadiazoles by treatment with potassium permanganate, or more conveniently, with ammonium cerium(IV) nitrate (CAN) are presented. CAN oxidation of 2,2-disubstituted 3-acyl-1,3,4-oxadiazolines, as well as that of aldehyde diacylhydrazones (open-chain isomers of 2,5-disubstituted 3-acyl-1,3,4- oxadiazolines) regenerates the parent carbonyl compounds.
- Somogyi, Laszlo
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p. 1235 - 1246
(2008/09/18)
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- Alum (KAl(SO4)2 ? 12H2O): An efficient and inexpensive catalyst for the one-pot synthesis of 1,3,4-oxadiazoles under solvent-free conditions
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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
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p. 1253 - 1255
(2008/03/28)
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- Silica sulfuric acid: An efficient and versatile acidic catalyst for the rapid and ecofriendly synthesis of 1,3,4-oxadiazoles at ambient temperature
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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
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p. 1201 - 1209
(2008/02/01)
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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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- Microwave assisted syntheses of 2,5-disubstituted 1,3,4-oxadiazoles
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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)
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- Zirconium(IV) chloride mediated cyclodehydration of 1,2-diacylhydrazines: A convenient synthesis of 2,5-diaryl 1,3,4-oxadiazoles
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Zirconium(IV) chloride was invented as a mild catalyst for the cyclodehydration of 1,2-diacylhydrazines. Efficient synthesis of several 2,5-disubstituted 1,3,4-oxadiazoles is reported.
- Sharma,Begum, Asra,Rakesh,Krishna, Palakodety Radha
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p. 2387 - 2391
(2007/10/03)
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- Facile synthesis of symmetric and unsymmetric 1,3,4-oxadiazoles using 2-acyl(or aroyl)pyridazin-3-ones
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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)
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- 2-Chloro-1,3-dimethylimidazolinium chloride. 2. Its application to the construction of heterocycles through dehydration reactions
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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)
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- Synthesis and Debenzoylation Products of Two Perbenzoylated 2-Substituted 5-D-Galactosyl- 1,3,4-oxadiazoles
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The synthesis of 2-(p-chlorophenyl)-5-[1′2′3′4′5′-penta-O-benzoyl- D-galactopentitol-1-yl]-1,3,4-oxadiazole is described. Its debenzoylation gave an equilibrium mixture of the 1,3,4-oxadiazole derivative without protection of the hydroxyl group and the N-
- Cannizzaro, Carina E.,Thiel, Inge M. E.,D'Accorso, Norma B.
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p. 481 - 484
(2007/10/03)
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