- Synthesis of 4-Organoselanyl-1H-pyrazoles: Oxone -Mediated Electrophilic Cyclization of α,β-Alkynyl Hydrazones by Using Diorganyl Diselenides
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A simple and efficient method for the synthesis of 4organoselanyl-1 H -pyrazoles has been developed, taking place under metal- and halogen-free conditions. Electrophilic species of selenium were easily generated in situ by the reaction of diorganyl diselenides with Oxone in ethanol as solvent in an open-flask at 70 °C. These electrophilic selenium species were employed in the selenylation/cyclization of α,β-alkynyl hydrazones, giving the title compounds in moderate to excellent yields. The final species of selenium obtained from the reaction of diphenyl diselenide with Oxone were characterized by 77 Se NMR spectroscopy and high-resolution mass spectrometry (HRMS).
- Perin, Gelson,Nobre, Patrick C.,Mailahn, Daniela H.,Silva, Márcio S.,Barcellos, Thiago,Jacob, Raquel G.,Lenard?o, Eder J.,Santi, Claudio,Roehrs, Juliano A.
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p. 2293 - 2304
(2019/05/24)
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- Csp3Csp3 bond cleavage in the palladium-catalyzed aminohydroxylation of allylic hydrazones using atmospheric oxygen as the sole oxidant
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A C-C bond cleavage was observed in the palladium-catalyzed aminohydroxylation of allylic hydrazones, using atmospheric oxygen as the sole oxidant. This reaction could also proceed in a one-pot manner, starting from keto-alkene compounds and phenylhydrazine.
- Chen, Yu-Chen,Zhu, Ming-Kui,Loh, Teck-Peng
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supporting information
p. 2712 - 2715
(2015/06/16)
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- PTSA-catalyzed Mannich-type-cyclization-oxidation tandem reactions: One-pot synthesis of 1,3,5-substituted pyrazoles from aldehydes, hydrazines and alkynes
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A convenient one-pot Mannich-type-cyclization-oxidation tandem process has been developed for the synthesis of 1,3,5-trisubstituted pyrazoles derivatives from aldehydes, hydrazines and alkynes using p-toluenesulfonic acid monohydrate (PTSA) as a multifunctional catalyst. This method provides a flexible and rapid route to 1,3,5-trisubstituted pyrazoles.
- Liu, Pei,Pan, Ying-Ming,Xu, Yan-Li,Wang, Heng-Shan
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supporting information; experimental part
p. 4696 - 4698
(2012/08/08)
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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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