Highly practical and cost-efficient synthesis of telmisartan: an antihypertensive drug

A novel and cost-efficient strategy for synthesis of an antihypertensive drug telmisartan, a substituted bis-benzimidazole derivative, is described. The key strategy is the construction of bis-benzimidazole 4 by reductive cyclization of o-nitroanilines 11 with butyl aldehyde and cyclocondensation of aromatic aldehydes 9 with o-phenylenediamine, then N-alkylation is allowed to give the target compound telmisartan after hydrolysis. The simple operation and workup procedure, along with the low production costs, make it suitable for industrial production and will benefits those with cardiovascular disease.