- Cross-Coupling between Hydrazine and Aryl Halides with Hydroxide Base at Low Loadings of Palladium by Rate-Determining Deprotonation of Bound Hydrazine
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Reported here is the Pd-catalyzed C–N coupling of hydrazine with (hetero)aryl chlorides and bromides to form aryl hydrazines with catalyst loadings as low as 100 ppm of Pd and KOH as base. Mechanistic studies revealed two catalyst resting states: an arylpalladium(II) hydroxide and arylpalladium(II) chloride. These compounds are present in two interconnected catalytic cycles and react with hydrazine and base or hydrazine alone to give the product. The selectivity of the hydroxide complex with hydrazine to form aryl over diaryl hydrazine was lower than that of the chloride complex, as well as the catalytic reaction. In contrast, the selectivity of the chloride complex closely matched that of the catalytic reaction, indicating that the aryl hydrazine is derived from this complex. Kinetic studies showed that the coupling process occurs by rate-limiting deprotonation of a hydrazine-bound arylpalladium(II) chloride complex to give an arylpalladium(II) hydrazido complex.
- Borate, Kailaskumar,Choi, Kyoungmin,Goetz, Roland,Hartwig, John F.,Shinde, Harish,Wang, Justin Y.,Zuend, Stephan J.
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supporting information
p. 399 - 408
(2020/10/29)
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- Isatin ursolate derivative as well as preparation method and application thereof
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The invention discloses an isatin ursolate derivative as well as a preparation method and application thereof, and belongs to the technical field of organic synthesis and medicinal chemistry. The structural general formula of the isatin ursolate derivativ
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Paragraph 0033; 0036; 0037
(2020/02/10)
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- One-Pot Synthesis of Indoles and Pyrazoles via Pd-Catalyzed Couplings/Cyclizations Enabled by Aqueous Micellar Catalysis
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An effective one-pot synthesis of either indoles or pyrazoles can be achieved via Pd-catalyzed aminations followed by subsequent cyclizations facilitated by aqueous micellar catalysis. This new technology includes efficient couplings with low loadings of palladium, a more stable source of the required hydrazine moiety, greater atom economy for the initial coupling, and reduced reaction temperatures, all leading to environmentally responsible processes.
- Akporji, Nnamdi,Braga, Felipe C.,Gabriel, Christopher M.,Landstrom, Evan B.,Lee, Nicholas R.,Lipshutz, Bruce H.
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supporting information
(2020/09/02)
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- Mild and rapid Pd-catalyzed cross-coupling with hydrazine in continuous flow: Application to the synthesis of functionalized heterocycles
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Minimizing risk: The synthesis of arylhydrazines through C?£?N cross-coupling of aryl chlorides with hydrazine is described. Through the use of continuous flow, the hazards associated with the use of hydrazine in the presence of transition metals are decreased. In addition, multistep flow sequences have also been developed for the generation of functionalized heterocycles utilizing the arylhydrazine intermediates.
- Deangelis, Andrew,Wang, Dong-Hui,Buchwald, Stephen L.
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supporting information
p. 3434 - 3437
(2013/05/09)
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- Antiimplantation Agents: Part I - 1-Arylthiosemicarbazides
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Several 1-arylthiosemicarbazides, 2-arylhydrazinothiazolines and 2-arylhydrazinodihydrothiazines have been examined for their antiimplantation activity in rats.Among the active compounds, 4-methyl-1-(3,5-bistrifluoromethylphenyl)thiosemicarbazide (3, C 2696-Go) and the corresponding 4,4-dimethyl (47), ethyl (4), n-butyl (5) and allyl (6) derivatives completely inhibit implantation at doses 10, 3, 20, 20 and 30 mg/kg respectively.The 3,4-dichlorophenyl analogue (32) is effective at a dose of 30 mg/kg. 2-(3,5-Bistrifluoromethylphenyl)hydrazinothiazoline (51) and the corresponding dihydrothiazine (63) show a weaker activity.The biological profile of C 2696-Go has been investigated in detail.It appears to prevent implantation by its antiuterotropic activity and ability to inhibit desiduoma formation.
- Nagarajan, K.,Talwalker, P.K.,Kulkarni, C.L.,Venkateswarlu, A.,Prabhu, S.S.,Nayak, G.V.
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p. 1243 - 1257
(2007/10/02)
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