Improved Synthesis of the Selective Rho-Kinase Inhibitor 6-Chloro-N4-{3,5-difluoro-4-[(3-methyl-1H-pyrrolo[2,3-b]pyridin-4-yl)oxy]phenyl}pyrimidin-2,4-diamine

A highly potent and selective Rho-kinase inhibitor containing a 7-azaindole moiety has been developed at Bayer Schering Pharma. Herein we disclose details of a significantly improved synthesis of the compound in 8.2% overall yield. Key aspects include cost and safety considerations and the uncommon use of a trifluoromethyl group with controllable reactivity as a masked methyl group.