Direct Pd(II)-Catalyzed Site-Selective C5-Arylation of 2-Pyridone Using Aryl Iodides
A straightforward Pd(II)-catalyzed general strategy was developed for the C5-selective arylation of the 2-pyridone core with easily available aryl iodides. The transformation was highly regioselective and accomplished with a wide scope and functional group tolerance. Silver nitrate played a crucial role in this direct site-selective arylation. The method was extended to synthesize biologically active molecules.
Pyridinethiones. IX Preparation of Ricinidine, Thioricinidine and Other 2(1H)-Pyridones and -thiones Related to Nicotinic acid
1(1H)-Pyridones and -thiones related to 1-substituted nicotinic acid derivatives have been prepared via the corresponding 1-substituted-3-formyl-2(1H)-pyridones and -thiones.A number of synthetic procedures for the interconversion of functional groups in these nicotinic acid derivatives are given i.e. preparation of the aldoximes, nitriles, carboxamides and carboxylic acids as well as the 3-hydroxyalkyl derivatives.The course of the basic peroxide oxidation of the 1-substituted-3-formyl-2(1H)-pyridinethiones is found to be very dependent upon the electronegativity ofthe 1-substituent.A preparation of ricinidine is also described.