- Rhodium-Catalyzed [4+2] Annulation of N-Aryl Pyrazolones with Diazo Compounds To Access Pyrazolone-Fused Cinnolines
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An efficient synthesis of novel dinitrogen-fused heterocycles such as pyrazolo[1,2-a]cinnoline derivatives have been accomplished by the rhodium(III)-catalyzed reaction of N-arylpyrazol-5-ones with α-diazo compounds. This reaction proceeds through a cascade C?H activation/intramolecular cyclization with a broad substrate scope. Furthermore, this protocol is successfully extended to the unusual phosphorus-containing α-diazo compounds and cyclic diazo compounds as the cross-coupling partners to deliver the two new kinds of pyrazolo[1,2-a]cinnolinones. The control experiments were performed to reveal insight into the mechanism of this reaction, involving reversible C?H activation, migratory insertion of the diazo compound, and cascade cyclization as the key steps of the transformation. Moreover, gram-scale synthesis and further transformation of the target product demonstrate the synthetic utility of the present protocol.
- Dhole, Sandip,Huang, Wan-Wen,Huang, Ying-Ti,Lin, Chih-Yu,Sun, Chung-Ming
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supporting information
p. 4984 - 4992
(2021/09/28)
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- Catalytic Asymmetric Addition of Diorganozinc Reagents to Pyrazole-4,5-Diones and Indoline-2,3-Diones
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The catalytic enantioselective diorganozinc additions to cyclic diketones including pyrazolin-4,5-diones and isatins have been developed. In the presence of morpholine-containing chiral amino alcohol ligand, the corresponding chiral cyclic tertiary alcohols were produced in good to excellent yields (up to 97 %) and enantioselectivities (up to 95 % ee). The notable feature of this protocol includes its mild reaction conditions, Lewis acid additives free and broad functional group tolerance.
- Wang, Rong-Hui,Li, Ya-Ling,He, Hong-Jiao,Xiao, You-Cai,Chen, Fen-Er
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supporting information
p. 4302 - 4306
(2021/02/16)
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- Synthesis of pyrazolones and pyrazoles via Pd-catalyzed aerobic oxidative dehydrogenation
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A palladium-catalyzed oxidative dehydrogenation reaction in the presence of AMS and base to synthesize pyrazolones and pyrazoles was identified. This method can be utilized to a wide range of substrates, operates under mild react conditions and can give high yields. We believe it could be used as an alternative protocol for the classical dehydrogenation reactions.
- Zhu, Ye-Fu,Wei, Bo-Le,Wei, Jiao-Jiao,Wang, Wen-Qiong,Song, Wei-Bin,Xuan, Li-Jiang
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supporting information
p. 1202 - 1205
(2019/03/29)
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- Palladium-catalyzed carbonylative coupling of α-chloroketones with hydrazines: a simple route to pyrazolone derivatives
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A range of pyrazol-5-one and pyrazol-3-one derivatives has been synthesized in a single step via a palladium-catalyzed carbonylation of aromatic or aliphatic α-chloroketones, in the presence of aromatic or aliphatic hydrazines. A reaction mechanism, explaining the observed regioselectivity, has been also discussed.
- Capua, Martina,Granito, Catia,Perrone, Serena,Salomone, Antonio,Troisi, Luigino
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p. 3363 - 3367
(2016/07/11)
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- A convenient microwave-assisted propylphosphonic anhydride (T3P mediated one-pot pyrazolone synthesis
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This paper describes a facile, efficient, and clean synthesis of various pyrazolones by employing T3P as a catalyst and performing the reaction under microwave irradiation. This two-step, one-pot reaction proceeded readily and tolerated a variety of functional groups. A wide range of pyrazolone derivatives were obtained in good to excellent yields. A one-pot, two-step procedure for the synthesis of pyrazolones is presented. This method, which uses T3P and microwave irradiation, is particularly easy to carry out and offers a notable alternative to the strongly acidic conditions that are generally employed with other synthetic approaches. Copyright
- Desroses, Matthieu,Jacques-Cordonnier, Marie-Caroline,Llona-Minguez, Sabin,Jacques, Sylvain,Koolmeister, Tobias,Helleday, Thomas,Scobie, Martin
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supporting information
p. 5879 - 5885
(2013/09/23)
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- Regioselective synthesis of heteroaryl triflones by LDA (lithium diisopropylamide)-mediated anionic thia-Fries rearrangement
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Novel heteroaryl triflones including oxindole, pyrazolone, pyridine, and quinoline derivatives have been regioselectively synthesized by LDA-mediated thia-Fries rearrangement for the first time. These reactions are also the first examples of the application of anionic thia-Fries rearrangement in heteroaromatic compounds.
- Xu, Xiu-Hua,Wang, Xin,Liu, Guo-Kai,Tokunaga, Etsuko,Shibata, Norio
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supporting information; experimental part
p. 2544 - 2547
(2012/07/14)
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- Multicomponent reactions of 1,3-disubstituted 5-pyrazolones and formaldehyde in environmentally benign solvent systems and their variations with more fundamental substrates
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Many multicomponent reactions (MCRs) of 1,3-disubstituted 5-pyrazolones and formaldehyde were developed in environmentally benign solvent systems. Styrenes, vinylferrocene and 2-phenylindoles could easily react, under solvent-free conditions or in glycerol solvent, with 1,3-disubstituted 5-pyrazolones and paraformaldehyde in the absence of any catalyst to afford a variety of complex skeletons in moderate to excellent yields. Particularly, these MCRs are proved to be combinable with the synthesis of 1,3-disubstituted 5-pyrazolones from phenylhydrazines and β-ketone esters in glycerol or a carboxylic acid-functionalized ionic liquid, [MIm-CO2H]BF 4. Therefore, some two-step sequential reactions of phenylhydrazines, β-ketone esters, formaldehyde and styrenes or indoles were developed for the first time. All these MCRs were conducted in environmentally benign solvent systems that not only minimize generation of wastes but also simplify the work-up procedure.
- Tan, Jia-Neng,Li, Minghao,Gu, Yanlong
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supporting information; experimental part
p. 908 - 914
(2010/09/07)
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- Potent hFPRL1 (ALXR) agonists as potential anti-inflammatory agents
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We report the discovery of potent agonists for the human formyl-peptide-like 1 receptor (hFPRL1). These compounds did not act at a closely related receptor denoted human formyl peptide receptor (hFPR) up to 10 μM concentration. Recent studies have indicat
- Buerli, Roland W.,Xu, Han,Zou, Xiaoming,Muller, Kristine,Golden, Jennifer,Frohn, Mike,Adlam, Matthew,Plant, Matthew H.,Wong, Min,McElvain, Michele,Regal, Kelly,Viswanadhan, Vellarkad N.,Tagari, Philip,Hungate, Randall
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p. 3713 - 3718
(2007/10/03)
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- Simple zwitterionic merocyanines as potential NLO chromophores
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A suite of zwitterionic pyridylidene-based merocyanines that contain no interconnecting π-bridge between the donor and acceptor rings has been synthesised and their second-order NLO properties evaluated largely by semi-empirical computational methods (MOP
- Kay,Woolhouse,Gainsford,Haskell,Wyss,Giffin,McKinnie,Barnes
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p. 2271 - 2281
(2007/10/03)
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- A facile preparation of o-aminoheteroarenecarbothialdehydes
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Reduction with hydrogen sulfide of heterocyclic o-azidoaldehydes yields the corresponding o-aminocarbothialdehydes as stable crystalline compounds. The reactions are exemplified in the pyrazole and indole series. The o-aminoheteroarencarbothialdehyde give
- Becher,Jorgensen,Frydendahl,Falt-Hansen
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p. 609 - 612
(2007/10/02)
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- Intramolecular Hetero-Diels-Alder Reaction of Alkylidene- and Benzylidenepyrazolones and Benzylideneisoxazolones. Investigations toward the Conformation of the Transition State
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Stereochemical aspects of the intramolecular hetero-Diels-Alder reaction of hetero dienes are studied.Knoevenagel condensation of aromatic aldehydes 1, 12, 15,, and 21 with pyrazolones 8a-h and isoxazolone 17 gave the corresponding hetero dienes, e.g.,9a-
- Tietze, Lutz F.,Brumby, Thomas,Pretor, Martina,Remberg, Gerd
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p. 810 - 820
(2007/10/02)
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