An Efficient and Impurity-Free Process for Telmisartan:  An Antihypertensive Drug

Abstract

Telmisartan (1), a substituted dibenzimidazole derivative, is an antihypertensive drug, essentially used to control blood pressure. An improved, cost-effective, and impurity-free process for telmisartan (1) suitable for large-scale production is described here by addressing various process development issues. The overall yield obtained from this newly developed process is around 50% (over five steps) compared to the literature reported process (21%, over eight steps).

Synthesis and characterization of 1'-benzyl-1,4'-dimethyl-2'propyl-1H,1'H-2,6'-dibenzimidazole derivatives and their antibacterial activity studies

“…The melting points (uncorrected) were measured on a SALACO apparatus. The compound 7, 1,7'-dimethyl-2'-propyl-1H,3'H-2,5'-dibenzimidazole have been synthesized as per the procedure given in the reference [21]. The compound 1,7'-dimethyl-2'-propyl-1H,3'H-2,5'-dibenzimidazole (1.0eq, 0.29g, 0.98mmol), substituted benzyl chloride (0.98mmol) and potassium carbonate (2.9mmol) in 15 mL of isopropyl alcohol was stirred with reflux for 4 hours.…”

A Modification to the Synthesis of Telmisartan: An Antihypertensive Drug

“…TLC was performed on Merck precoated Silica-gel 60F 254 plates. 1 H and 13 C NMR spectra were recorded in DMSO-d 6 and CDCl 3 using 400 MHz, on a Varian Gemini 400 MHz FT NMR spectrometer. The chemical shifts were reported in δ ppm relative to TMS.…”

“…Alkylation of compound 1,7p-dimethyl-2p-propyl-1H,3pH-2,5p-bibenzo [d] imidazole [5][6][7] 4 with 4p-bromomethyl-biphenyl-2-carboxylic acid tert-butyl ester 5 furnished ester derivative of Telmisartan 6. Hydrolysis of the ester 6 in trifluoroacetic acid yielded Telmisartan 1 in an overall yield of around 21% containing several impurities.…”

Antihypertensive Drugs

“…Other minor changes in these two principal schemes were proposed [136][137][138][139][140][141][142].…”