Identification of the side products that diminish the yields of the monoamidated product in metal-catalyzed C−H amidation of 2‑phenylpyridine with arylisocyanates

The Ru(II)-catalyzed amidation of 2-arylpyridines with aryl isocyanates via C–H bond activation is less efficient than described previously, due to the formation of a series of side products, which were readily identified using direct infusion electrospray mass spectrometry and high-performance liquid chromatography–mass spectrometry.