- From Phenylhydrazone to 1H-1,2,4-Triazoles via Nitrification, Reduction and Cyclization
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Herein we report an annulation of phenylhydrazone via a tandem nitrification, reduction, cyclization protocol employing cobalt nitrate and 1,2-dichloroethane to produce substituted 1H-1,2,4-triazoles. Notably, 1,2-dichloroethane serves both the solvent and a hydrogen source for transfer hydrogenation. This methodology works under mild conditions, providing a direct approach for the synthesis of 1H-1,2,4-triazoles. (Figure presented.).
- Hao, Liqiang,Wang, Guodong,Sun, Jian,Xu, Jun,Li, Hongshuang,Duan, Guiyun,Xia, Chengcai,Zhang, Pengfei
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supporting information
p. 1657 - 1662
(2020/03/19)
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- sp2-C–H Acetoxylation of Diversely Substituted (E)-1-(Arylmethylene)-2-phenylhydrazines Using PhI(OAc)2 as Acetoxy Source at Ambient Conditions
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A catalyst- and additive-free simple and straightforward method for regioselective direct sp2 C–H acetoxylation reaction of aldehyde hydrazones has been achieved at ambient temperature employing PIDA as an acetoxy source. The scope of the reaction has been successfully verified with a wide range of biologically important aldehyde hydrazones with diverse functional group tolerance. The method is highly selective, mild and efficient, operationally simple, rapid and high-yielding.
- Brahmachari, Goutam,Karmakar, Indrajit
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supporting information
p. 5925 - 5933
(2019/08/16)
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- Simple and efficient approach for synthesis of hydrazones from carbonyl compounds and hydrazides catalyzed by meglumine
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A simple, environmentally benign protocol for synthesis of hydrazones from carbonyl compounds and hydrazides has been developed in the presence of meglumine in aqueous-ethanol media at room temperature. The salient features of the present protocol are mild reaction conditions, short reaction time, high yields, operational simplicity, metal-free, applicability toward large-scale synthesis, and biodegradable and inexpensive catalyst.
- Zhang, Mo,Shang, Ze-Ren,Li, Xiao-Tang,Zhang, Jia-Nan,Wang, Yong,Li, Kang,Li, Yang-Yang,Zhang, Zhan-Hui
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p. 178 - 187
(2017/01/10)
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- Oxidized single-walled carbon nanotubes (swcns-cooh) as a new catalyst for the protection of carbonyl groups as hydrazones
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Nano-materials are considered as suitable heterogeneous catalysts for many organic reactions. Herein oxidized carbon nanotube (SWCNTs-COOH) has been reported as a heterogeneous catalyst, for protection of carbonyl groups as hydrazones in EtOH at 80 C. The reactions proceed smoothly with good to excellent yields, and the SWCNTs-COOH used can be recycled.
- Borazjani, Maryam Kiani,Safaei, Hamid Reza,Panahandeh, Majid,Kiani, Ali Reza,Kiani, Masoumeh,Mofarahi, Masoud
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p. 279 - 281
(2013/12/04)
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- Diaryl hydrazones as multifunctional inhibitors of amyloid self-assembly
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The design and application of an effective, new class of multifunctional small molecule inhibitors of amyloid self-assembly are described. Several compounds based on the diaryl hydrazone scaffold were designed. Forty-four substituted derivatives of this core structure were synthesized using a variety of benzaldehydes and phenylhydrazines and characterized. The inhibitor candidates were evaluated in multiple assays, including the inhibition of amyloid β (Aβ) fibrillogenesis and oligomer formation and the reverse processes, the disassembly of preformed fibrils and oligomers. Because the structure of the hydrazone-based inhibitors mimics the redox features of the antioxidant resveratrol, the radical scavenging effect of the compounds was evaluated by colorimetric assays against 2,2-diphenyl-1-picrylhydrazyl and superoxide radicals. The hydrazone scaffold was active in all of the different assays. The structure-activity relationship revealed that the substituents on the aromatic rings had a considerable effect on the overall activity of the compounds. The inhibitors showed strong activity in fibrillogenesis inhibition and disassembly, and even greater potency in the inhibition of oligomer formation and oligomer disassembly. Supporting the quantitative fluorometric and colorimetric assays, size exclusion chromatographic studies indicated that the best compounds practically eliminated or substantially inhibited the formation of soluble, aggregated Aβ species, as well. Atomic force microscopy was also applied to monitor the morphology of Aβ deposits. The compounds also possessed the predicted antioxidant properties; approximately 30% of the synthesized compounds showed a radical scavenging effect equal to or better than that of resveratrol or ascorbic acid.
- T?r?k, Béla,Sood, Abha,Bag, Seema,Tulsan, Rekha,Ghosh, Sanjukta,Borkin, Dmitry,Kennedy, Arleen R.,Melanson, Michelle,Madden, Richard,Zhou, Weihong,Levine, Harry,T?r?k, Marianna
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p. 1137 - 1148
(2013/08/24)
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- Copper-mediated synthesis of substituted 2-aryl-N-benzylbenzimidazoles and 2-arylbenzoxazoles via C-H functionalization/C-N/C-O bond formation
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An efficient method for the transformation of N-benzyl bisarylhydrazones and bisaryloxime ethers to functionalized 2-aryl-N-benzylbenzimidazoles and 2-arylbenzoxazoles is described. The protocol involves a copper(II)-mediated cascade C-H functionalization/C-N/C-O bond formation under neutral conditions. Substrates having either electron-donating or -withdrawing substituents undergo the cyclization to afford the target heterocycles at moderate temperature.
- Guru, Murali Mohan,Ali, Md Ashif,Punniyamurthy, Tharmalingam
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p. 5295 - 5308
(2011/08/05)
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- Magnesium perchlorate as an efficient catalyst for the synthesis of imines and phenylhydrazones
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Magnesium perchlorate has been found to be an efficient catalyst for the synthesis of imines and phenylhydrazones by the reaction of carbonyl compounds with amines and phenylhydrazine in high yields at room temperatures and in short times. The condensation of less electrophilic carbonyl compounds with poorly nucleophilic amines affords the imines in excellent yields.
- Chakraborti, Asit K.,Bhagat, Srikant,Rudrawar, Santosh
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p. 7641 - 7644
(2007/10/03)
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