A direct arylation of pyrazolo­[1,5-a]­pyridines with aryl iodides selectively occurring at the C-3 and C-7 positions via palladium-catalyzed C–H activation is described. In these reactions, (a) cesium­(I) fluoride and (b) silver­(I) carbonate were employed as the additive to afford 3- and 7-arylated pyrazolo­[1,5-a]­pyridines, respectively, in modest to good yields. These reactions showed good compatibility with functional groups, and the catalytic mechanisms of these reactions were proposed. Finally, the synthetic application on the potent p38 kinase inhibitors was demonstrated.

A synthetic methodology for the late-stage ortho-C–H bond aroylation of anilines with aryl aldehydes led to a variety of ortho-aroylated anilines by the use of palladium­(II) acetate, tert-butyl hydroperoxide, and 1,4-dioxane as the catalyst, oxidant, and solvent, respectively, is presented. An N-phenylpyridin-2-amine palladacycle was isolated and characterized by X-ray crystallography. Controlled experiments, radical trapping experiments, and the experiments of the kinetic isotope effect were undertaken to support the proposed reaction mechanism. Syntheses of 2-aminobenzophenone and 9­(10H)-acridanone based on the developed methodology were successfully demonstrated.