A Palladium-Catalysed Urea Arylation Route to a CRF1 Receptor Antagonist

A new synthetic approach to a potent CRF antagonist, GW808990 (NBI35583), is reported. The route hinges on the palladium-catalysed intramolecular arylation of a urea with 2-chloropyridine. Spontaneous piperazine ring closure means that a high-yielding bisannulation reaction is the final step.