Regioselective Synthesis of 1-Aryl-3,4-substituted/annulated-5-(methylthio)pyrazoles and 1-Aryl-3-(methylthio)-4,5-substituted/annulated Pyrazoles
摘要:
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 alpha-oxoketene dithioacetals or beta-oxodithioesters.
A palladium-catalyzedoxidative carbonylation of arylhydrazines and alkynes with balloon pressure CO/O2 to afford trisubstituted pyrazoles in a one-pot manner has been developed. The formation of trisubstituted pyrazoles involves a sequential C–N bond cleavage, carbonylation, Sonogashira coupling, Michael addition, and intramolecular condensation cyclization tandem process. An unprecedented oxidative
已经开发了用球罐压力CO / O 2进行钯催化的芳基肼和炔烃的氧化羰基化反应,以一锅法得到三取代的吡唑。三取代吡唑的形成涉及连续的C–N键断裂,羰基化,Sonogashira偶联,迈克尔加成和分子内缩合环化串联过程。芳基肼的空前的氧化Sonogashira-羰基化反应在如此简便的吡唑方法中起着关键作用。
Synthesis of 4-Organoselanyl-1H-pyrazoles: Oxone®-Mediated Electrophilic Cyclization of α,β-Alkynyl Hydrazones by Using Diorganyl Diselenides
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