Continuous Flow Synthesis of Telmisartan enabled by SiliaCat DPP-Pd

SiliaCat DPP-Pd promotes the key Suzuki coupling step in the synthesis of Telmisartan, an antihypertensive drug, under continuous flow conditions.

Telmisartan (Micardis) is an antihypertensive drug that recently lost patent protection in the United States. Hence, there is interest in the development of novel synthetic schemes for this molecule. The classical batch approach was modified to a flow process, thus telescoping three steps (N-alkylation, saponification, Suzuki coupling) without isolation of intermediates or solvent exchange. The key Suzuki coupling, which previously used PdCl₂dppf under homogeneous, batch conditions, was enabled by SiliaCat DPP-Pd. The heterogenous catalyst was packed in a flow cartridge mounted on a ThalesNano X-Cube. This new strategy cleanly yielded Talmisartan in 81% yield (1 mg/min) over three steps in 97% purity after simple aqueous workup.

Keywords:
Flow chemistry, bioactive compounds, Suzuki coupling, Telmisartan