Synthesis of 5,7-Dichloro-6-azaindolesand Functionalization via a Highly Selective Lithium-Chlorine Exchange

The synthesis of a range of novel 5,7-dichloro-6-azaindoles through the use of a Fischer cyclization with pyridine hydrochloride in N-methylpyrrolidin-2-one is described. Dichloro-6-azaindoles are versatile compounds that can be selectively substituted through a palladium-catalyzed cross-coupling reaction or a high-yielding lithium-chlorine exchange.