Route Design and Development of a MET Kinase Inhibitor: A Copper-Catalyzed Preparation of an N1-Methylindazole

The synthesis of a MET kinase inhibitor in an overall yield of 22% was achieved over eight steps starting with 3-hydroxybenzaldehyde, an improvement from the initial 12-step process with a 5.4% yield. Highlights of the process chemistry design and development are a Cu-catalyzed cyclization to form an important N1-methylindazole ring, a selective nitro reduction in the presence of an aryl bromide, a late-stage Suzuki cross-coupling, and a base-promoted Boc deprotection to form the desired drug candidate.