Authors:Alex D. Martin, Ali R. Siamaki, Katherine Belecki and B. Frank Gupton
A highly efficient continuous synthesis has been developed for telmisartan, the active ingredient in the antihypertensive drug, Micardis. This synthetic route employs a convergent strategy that requires no intermediate purifications or solvent exchanges. The key step in the reaction scheme is a Suzuki cross-coupling reaction between two functionalized benzimidazoles that is catalyzed by a solid-supported Pd catalyst. This flow-based approach utilizes a tubular reactor system coupled with a plug flow packed bed cartridge unit that produces telmisartan in an 81% isolated yield.