A new method for free radical methylation of pyrimidinones and pyridinones with dicumylperoxide (DCP) under metal-free condition is introduced. A 50 g-scale reaction could be performed safely at desired...
The reactions of 1-unsubstituted 2-pyridones with benzyne afforded the Diels-Alder adduct, 5, 6-benzo-2-azabarrelen-3 (2H)-ones, together with a large amount of the Michael-type adduct, 2-phenoxypyridines.
The reactions of 2-pyridones with benzyne were investigated in order to gain some insight into the structure–reactivity–chemoselectivity relationship involved in the tautomeric systems. All reactions examined have resulted in the formation of Diels-Alder and Michael-type adducts. It has been shown that the Diels-Alder reactivities were well correlated with the HOMO energy levels of the 2-pyridone form and the yields of the Michael-type adduct were closely associated with the tautomeric equilibria. In summary, the chemoselectivities of 2-pyridones in the reaction with benzyne were largely affected by the tautomeric properties.
2-Pyridones from Cyanoacetamides and Enecarbonyl Compounds: Application to the Synthesis of Nothapodytine B
作者:Lionel Carles、Kesavaram Narkunan、Sébastien Penlou、Laurence Rousset、Denis Bouchu、Marco A. Ciufolini
DOI:10.1021/jo025546d
日期:2002.6.1
The condensation of an enone or enal with cyanoacetamide derivatives and t-BuOK furnishes either 3-eyano-2-pyridones or 3-unsubstituted-2-pyridones, depending on whether the reaction is carried out in the presence or in the absence Of O-2. In the first case, in situ oxidation of Michael-type intermediates takes place; in the second case, the products result from "decyanidative aromatization" of such intermediates. A one-step synthesis of 3-alkyl-2-pyridones has been devised on the basis of decyanative union of an enone/enal and a 2-alkyleyanoacetamide. The new reaction forms the centerpiece of an unusually concise synthesis of nothapodytine B (mappicine ketone).