- Experimental and quantum chemical studies of the structural and spectral properties of novel diazenyl formazans
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A new series of 3-(p-substitutedphenyl)-5-phenyl-1-(4-phenyldiazenyl)phenylformazans were synthesized by coupling p-substituted phenyl or pyridinylhydrazones with p-aminoazobenzene diazonium chloride. All compounds were characterized by FT-IR, UV–Vis, 1H NMR, and 13C NMR spectroscopic techniques, and HR-MS. DFT was used to calculate the molecular structures and 1H and 13C chemical shift values of the synthesized compounds with PBE1PBE functional and 6-311G(2d,2p)basis set combination. The IR spectra of the novel formazans were calculated using DFT at PBE1PBE/6-311G(d,p)level of theory. The electronic absorption spectra of the optimized structures were evaluated by TD-DFT method at PBE1PBE/6-311G(2d,2p)level of theory. The absorption spectra of the synthesized diazenyl formazans were investigated in three different solvents. A good correlation was established between the experimental data and calculated results.
- Tezcan, Habibe,?en?z, Hülya,Tokay, Nesrin
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- A novel chemoselective synthesis of 3H-spiro[isobenzofuran-1,3'-pyrazole] derivatives by oxidative cleavage of their corresponding dihydroindeno[1,2-c]pyrazoles
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Abstract This paper reports a new and simple procedure for the synthesis of 3H-spiro[isobenzofuran-1,3'-pyrazole] derivatives by reacting 1-benzylidene-2-phenylhydrazine derivatives with ninhydrin in acetic acid medium at room temperature followed by oxidative cleavage of their corresponding dihydroindeno[1,2-c]pyrazoles. 1-Benzylidene-2-phenylhydrazine derivatives were prepared via the reaction between phenylhydrazine and benzaldehyde derivatives. Easy procedure, mild reaction conditions, high yields in short reaction times, availability of starting materials, and no formation of by-product are the advantages of this approach.
- Mohammadizadeh, Mohammad Reza,Basti, Fatemeh
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- Synthesis of 1,1′-([1,1′-Biphenyl]-4,4′-diyl)bis(3-aryl-5-phenylformazans) and 1,1′-([1,1′-Biphenyl]-4,4′-diyl)bis(3-aryl-5-phenyl-5,6-dihydro-1,2,4,5-tetrazin-1-ium) Perchlorates
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Abstract: New bis-formazans and bis(5,6-dihydro-1,2,4,5-tetrazin-1-ium) perchlorates were synthesized with high yields under mild conditions. 1,1′-([1,1′-Biphenyl]-4,4′-diyl)bis(3-aryl-5-phenylformazans) were obtained by diazo coupling of para-substituted benzaldehyde phenylhydrazones with [1,1′-biphenyl]-4,4′-bis(diazonium chloride). Treatment of the obtained bis-formazans with formaldehyde in the presence of perchloric acid in dioxane afforded 1,1′-([1,1′-biphenyl]-4,4′-diyl)bis(3-aryl-5-phenyl-5,6-dihydro-1,2,4,5-tetrazin-1-ium) diper-chlorates. The structure of the synthesized compounds was confirmed by elemental analyses and UV, IR, and 1H and 13C NMR spectra.
- Alalwan, D. H. K.,Jassim, T.,Kostryukov, S. G.,Kozlov, A. Sh.,Masterova, Yu. Yu.,Tezikova, V. S.
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p. 1600 - 1607
(2021/12/13)
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- Sequential [3+2] annulation reaction of prop-2-ynylsulfonium salts and hydrazonyl chlorides: Synthesis of pyrazoles containing functional motifs
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A novel sequential [3+2] annulation reaction has been developed using prop-2-ynylsulfonium salts and hydrazonyl chlorides, affording a series of pyrazoles with functional motifs that can be post modified in the preparation of various drugs or drug candidates. Further transformation and gram-scale operations could also be achieved efficiently. This journal is
- Jia, Tingting,Liu, Shourong,Shao, Jiaan,Shi, Tao,Wu, Zhaoxiao,Zeng, Linghui,Zhang, Chong,Zhang, Jiankang,Zhu, Huajian,Zhuang, Rangxiao
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supporting information
p. 8460 - 8463
(2021/09/08)
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- Synthesis and Electrochemical Properties of 2-(4-R1-Phenyl)-6-(4-R2-phenyl)-4-phenyl-3,4-dihydro1,2,4,5-tetrazin-1(2H)-yls
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Abstract: A new methodology for creating electroactive components for organic batteries,based on the construction of a molecular platform including stable3,4-dihydro-1,2,4,5-tetrazin-1(2H)-ylradicals was described. A series of2-(4-R1-phenyl)-6-(4-R2-phenyl)-4-phenyl-3,4-dihydro-1,2,4,5-tetrazin-1(2H)-yls with substituents of various nature wasobtained. It was shown that the substituents R1 inthe aromatic ring at position 2 of the tetrazinyl fragment influence the valueof the oxidation potential in the radical, but do not influence the value of thereduction potentials, while the substituent R2 of thearomatic ring at position 6 influence the values of the reduction potentials andpractically do not influence oxidation potential values. Based on the obtainedelectrochemical data, a correlation structure–potential value was revealed forthe cathodic and anodic process, with the help of which triarylsubstituted3,4-dihydro-1,2,4,5-tetrazin-1(2H)-ylradicals with high values of the electrochemical gap were obtained.
- Akhmatova, A. A.,Balandina, A. V.,Chernyaeva, O. Yu.,Kostryukov, S. G.,Kozlov, A. Sh.,Kraynov, E. V.,Lukshina, Yu. I.,Pryanichnikova, M. K.
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p. 341 - 351
(2020/04/27)
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- Triarylverdazyl radicals as promising redox-active components of rechargeable organic batteries
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A novel design of electroactive components of rechargeable organic batteries based on stable verdazyl radicals bearing various substituents is proposed. 3-Positioned aromatic substituents at the verdazyl moiety affect the reduction potentials and almost do not affect the oxidation potential, while 1-positioned aromatic substituents affect contrariwise the oxidation potential of this radical without any influence on the reduction potential. The acquired electrochemical data allowed us to reveal the structure—potential relationship for the cathodic and anodic processes, which provided the design of triarylverdazyl radicals possessing record-breaking parameters of the “electrochemical gap”.
- Burtasov, A. A.,Chernyaeva, O. Yu.,Kostryukov, S. G.,Kozlov, A. Sh.,Pryanichnikova, M. K.,Tanaseichuk, B. S.
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p. 1321 - 1328
(2020/09/07)
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- Acid-Mediated Three Component Assembly of 4-Fluoropyrazoles from α-Fluoronitroalkenes, Hydrazines, and Aldehydes
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A new approach for the synthesis of highly pharmaceutically relevant 4-fluoropyrazoles via oxidative annulation of α-fluoronitroalkenes with in situ prepared hydrazones was developed. The reaction is efficiently promoted by trifluoroacetic acid while atmo
- Ioffe, Sema L.,Motornov, Vladimir A.,Nelyubina, Yulia V.,Nenajdenko, Valentine G.,Tabolin, Andrey A.
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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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- Synthesis of hybrid polycycles containing fused hydroxy benzofuran and 1H-indazoles via a domino cyclization reaction
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A stoichiometry controlled domino cyclization reaction of hydrazone and p-benzoquinone to an angularly fused 3H-benzofuro[3,2-e]indazole core with an embedded oxygenated dibenzofuran framework under mild reaction conditions is disclosed. The reaction involves palladium catalyzed 5-hydroxy-1H-indazole formation followed by TFA mediated [3+2] annulation between the in situ formed 5-hydroxy-1H-indazole and p-benzoquinone. The developed method is attractive because of the concomitant formation of two heterocyclic rings with consecutive multiple bond forming events that include two C-C, one C-N and one C-O bonds. Spectroscopic and theoretical studies of the blue emissive benzofuroindazole derivatives have also been described.
- Janardhanan, Jith C.,James, Kiran,Puthuvakkal, Anisha,Bhaskaran, Rasmi P.,Suresh, Cherumuttathu H.,Praveen, Vakayil K.,Manoj, Narayanapillai,Babu, Beneesh P.
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p. 10166 - 10175
(2019/07/03)
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- Stereospecific copper(II)-catalyzed tandem ring opening/oxidative alkylation of donor-acceptor cyclopropanes with hydrazones: Synthesis of tetrahydropyridazines
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Aerobic copper(II)-catalyzed tandem ring opening and oxidative C-H alkylation of donor-acceptor cyclopropanes with bisaryl hydrazones is accomplished to produce tetrahydropyridazines, in which copper(II) plays dual role as a Lewis acid as well as redox catalyst. The reaction is stereospecific, and optically active cyclopropanes can be reacted with high optical purities (89-98% enantiomeric excess). The substrate scope, functional group tolerance, dual role of the copper(II) catalyst, and the use of air as an oxidant are the important practical features. A product bearing a 3-bromoaryl group can be subjected to Pd-catalyzed Suzuki coupling with boronic acid in high yield.
- Mishra, Manmath,De, Pinaki Bhusan,Pradhan, Sourav,Punniyamurthy, Tharmalingam
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p. 10901 - 10910
(2019/09/13)
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- Ion-pairing catalysis in the enantioselective addition of hydrazones to N-acyldihydropyrrole derivatives
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We have demonstrated that dihydropyrrole-based enamide derivatives can act as efficient precursors of chiral quaternary N-acyliminium salts under Br?nsted acid catalysis that undergo reactions with hydrazones, the latter participating as masked nucleophilic carbonyl group equivalents. The optimized methodology provides a variety of enantiopure α-substituted proline derivatives in excellent yields, being even compatible with disubstituted β-enamides that generate two contiguous stereocentres.
- Zabaleta, Nagore,Uria, Uxue,Reyes, Efraim,Carrillo, Luisa,Vicario, Jose L.
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supporting information
p. 8905 - 8908
(2018/08/17)
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- An efficient five-component synthesis of thioether containing dihydropyrano[2,3-c]pyrazoles: a green domino strategy
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An efficient route for the synthesis of novel thioether containing dihydropyrano[2,3-c]pyrazoles has been accomplished via a solvent-free, catalyst-free, one-pot, five component domino strategy. This synthetic approach offers several advantages such as an easy work-up, no need for purification techniques and a short reaction time with good atom economy and high yields of the products (81-86%).
- Ramesh, Vediyappan,Shanmugam, Sivakumar,Devi, Natarajan Savitha
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p. 9993 - 10001
(2016/12/07)
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- Radical Addition of Hydrazones by α-Bromo Ketones to Prepare 1,3,5-Trisubstituted Pyrazoles via Visible Light Catalysis
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A novel efficient tandem reaction of hydrazones and α-bromo ketones is reported for the preparation of 1,3,5-trisubstituted pyrazoles by visible light catalysis. In this system, the monosubstituted hydrazones show wonderful reaction activity with alkyl radicals, generated from α-bromo ketones. A radical addition followed by intramolecular cyclization affords the important pyrazole skeleton in good to excellent yields. This efficient strategy under mild conditions with wide group tolerance provides a potential approach to the 1,3,5-trisubstituted pyrazoles.
- Fan, Xiu-Wei,Lei, Tao,Zhou, Chao,Meng, Qing-Yuan,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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p. 7127 - 7133
(2016/08/30)
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- Divergent construction of pyrazoles via Michael addition of n -arylhydrazones to 1,2-diaza-1,3-dienes
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The base (NaH)-promoted Michael addition of N-arylhydrazones (AHs) with 1,2-diaza-1,3-dienes (DDs) produces unprecedented β-azohydrazone adducts. Strategically, the use of AHs as acyl anion equivalents (d1 synthon) and DDs as α-electrophiles (a
- Mantenuto, Serena,Mantellini, Fabio,Favi, Gianfranco,Attanasi, Orazio A.
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supporting information
p. 2014 - 2017
(2015/04/27)
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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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- Synthesis of substituted 1 H-indazoles from arynes and hydrazones
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The 1H-indazole skeleton can be constructed by a [3 + 2] annulation approach from arynes and hydrazones. Under different reaction conditions, both N-tosylhydrazones and N-aryl/alkylhydrazones can be used to afford a variety of indazoles. The former reaction affords 3-substituted indazoles either via in situ generated diazo compounds or through an annulation/elimination process. The latter reaction leads to 1,3-disubstituted indazoles likely through an annulation/oxidation process. The reactions operate under mild conditions and can accommodate aryl, vinyl, and less satisfactorily, alkyl groups.
- Li, Pan,Wu, Chunrui,Zhao, Jingjing,Rogness, Donald C.,Shi, Feng
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experimental part
p. 3149 - 3158
(2012/07/14)
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- Synthesis and stereochemistry of some novel dihydropyrrolo[3,4-c]pyrazoles
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Eleven novel dihydropyrrolo[3,4-c]pyrazole derivatives were obtained by the reaction of chiral (1R)-N-(1-phenylethyl)maleimide and C,N-aryl-substituted nitril-imines. The reaction afforded the cycloadducts as a regioisomeric mixture which can be separable in some cases. The structure and stereochemistry of cycloadducts were assigned on the basis of infrared (IR), 1H and 13C nuclear magnetic resonance (NMR), mass and X-ray spectra, optical rotation measurements, and CHN analyses.
- Dueruest, Yasar,Yildirm, Muhammet,Fronczek, Chris F.,Fronczek, Frank R.
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scheme or table
p. 127 - 138
(2012/07/27)
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