Practical way to imidazo[4,5-b] and [4,5-c]pyridine-2-ones via cascade ureidation/palladium-catalyzed cyclization.

We developed an efficient one-pot tandem carbamoyl chloride amination and palladium-catalyzed intramolecular urea cyclization, which furnished high-throughput access to imidazo[4,5-b]pyridine-2-one and related imidazo[4,5-c]pyridine-2-one ring systems. Moderate to excellent yields were reported.