- Regioselective rapid analog synthesis of 1,3-(or 1,5-)diphenyl-4-aryl/ heteroaryl-5-(or 3-)(methylthio)pyrazoles via Suzuki cross-coupling
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Regioselective routes for the synthesis of 1,3-(or 1,5-)diphenyl-4-aryl/ heteroaryl-5-(or 3-)(methylthio)pyrazoles via Suzuki cross-coupling of 4-bromo (or 4-iodo)-1,3-(or 1,5-)diphenyl-5-(or 3-)(methylthio)pyrazoles have been reported.
- Khan, Taukeer A.,Kumar, Sarvesh,Venkatesh, Chelvam,Ila, Hiriyakkanavar
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experimental part
p. 2961 - 2968
(2011/05/05)
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- Pyrazole synthesis using a titanium-catalyzed multicomponent coupling reaction and synthesis of withasomnine
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The titanium-catalyzed 3-component coupling of an alkyne, isonitrile, and amine can be used to generate tautomers of 1,3-diimines. These diimines produced in situ undergo cyclization with hydrazine and hydrazine derivatives in a one-pot procedure to provi
- Majumder, Supriyo,Gipson, Kevin R.,Staples, Richard J.,Odom, Aaron L.
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experimental part
p. 2013 - 2023
(2011/02/28)
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- The chemistry of α,β-ditosyloxyketones: new and convenient route for the synthesis of 1,4,5-trisubstituted pyrazoles from α,β-chalcone ditosylates
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The reaction of α,β-chalcone ditosylates with various reagents such as phenylhydrazine hydrochloride, semicarbazide hydrochloride and thiosemicarbazide in suitable conditions leads to 1,2-aryl shift, thereby providing a novel route for the synthesis of 1,4,5-trisubstituted pyrazoles.
- Prakash, Om,Sharma, Deepak,Kamal, Raj,Kumar, Rajesh,Nair, Reshmi R.
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experimental part
p. 10175 - 10181
(2010/02/27)
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- Regioselective synthesis of 1-aryl-3,4-substituted/annulated-5-(methylthio) pyrazoles and 1-aryl-3-(methylthio)-4,5-substituted/annulated pyrazoles
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Highly efficient and regioselective synthesis of 1-aryl-3,4-substituted/ annulated-5-(methylthio)-pyrazoles and 1-aryl-3-(methylthio)-4,5-substituted/ annulated pyrazoles has been reported via cyclocondensation of arylhydrazines with either α-oxoketene dithioacetals or β-oxodithioesters.
- Peruncheralathan,Khan,Ila,Junjappa
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p. 10030 - 10035
(2007/10/03)
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- A Combination of Tandem Amine-Exchange/Heterocyclization and Biaryl Coupling Reactions for the Straightforward Preparation of Phenanthro[9,10-d]pyrazoles
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The tandem amine-exchange/heterocyclization of enaminoketones is successfully applied to the regioselective preparation of a series of new 4,5-diarylpyrazoles by reaction of phenylhydrazine and several 3-N,N-(dimethylamino)-1,2-diarylpropenones. The comparison of a vast array of biaryl coupling procedures provides general, complementary approaches to new phenanthro[9,10-d]-pyrazoles. The most efficient procedures for this final step in the construction of the tetracyclic system are based on a Stille-type tandem stannylation - biaryl coupling of o,o′-dihalogenated diarylpyrazoles and an hypervalent iodine-mediated nonphenolic oxidative coupling of nonhalogenated precursors.
- Olivera, Roberto,SanMartin, Raul,Dominguez, Esther
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p. 7010 - 7019
(2007/10/03)
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- A straightforward synthetic pathway to phenanthro[9,10-d]heterocycles
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A series of new 4,5-o,o-bis(haloaryl)pyrazoles was regioselectively prepared by a tandem amine exchange/heterocyclization. The intramolecular Stille-type biaryl coupling of the so-obtained pyrazole derivatives and previously prepared diarylisoxazoles led with high overall yields to the isolation of new phenanthro[9,10-d]pyrazoles and phenanthro[9,10- d]isoxazoles, respectively. The formation of dehalogenation products was efficiently avoided by use of heavy-wall pressure tubes.
- Olivera, Roberto,SanMartin, Raúl,Domínguez, Esther
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p. 1028 - 1030
(2007/10/03)
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- The Reactions of Monoalkylthio- or Monoarylthio-Substituted Cyclopropenium Salt with Nitrogen Nucleophiles: Formation of Polyfunctionally Substituted Pyrroles or Pyrazoles
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The reactions of monoalkylthio- or monoarylthio-substituted cyclopropenium salt (1) with a number of secondary amines were studied.The amines, such as N-methylaniline, yielded indenes, whereas N-alkyl- or N-arylbenzylamines gave 1-alkyl or 1-aryl-2-phenyl
- Yoshida, Hiroshi,Utsumi, Fumitaka,Suzuki, Hideki,Ito, Satoru,Sakashita, Shin-ichi,et al
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p. 698 - 702
(2007/10/02)
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