Design, synthesis and biological evaluation of new 5-nitro benzimidazole derivatives as AT1 antagonists with anti-hypertension activities.

The design, synthesis, in vitro and in vivo evaluation of 5-nitro benzimidazole with 1,4-disubsituted or 1,5-disubsituted indole derivatives as novel angiotensin II receptor antagonist is outlined. Radioligand binding assays showed that 2-(4-((2-butyl-5-nitro-1H-benzo[d]imidazol-1-yl)methyl)-1H-indol-1-yl)benzoic acid, compound 3, displayed a high affinity for the angiotensin II type 1 receptor with IC50 value of 1.03±0.26nM. The biological evaluation on spontaneously hypertensive rats and renal hypertensive rats showed that 3 could cause significant decrease on MBP in a dose dependent manner, whose maximal response lowered 30mmHg of MBP at 5mg/kg and 41mmHg of MBP at 10mg/kg after oral administration, and the significant antihypertensive effect lasted beyond 24h, which is better than Losartan. Taken together 3 could be considered as an effective and durable anti-hypertension drug candidate. These encouraging results are deserved of further investigation towards its use for therapeutic benefit.