Synthesis and biological evaluation of novel potent angiotensin II receptor antagonists with anti-hypertension effect

A series of novel angiotensin II type 1 receptor antagonists were prepared. Radioligand binding assay suggested that compounds 1b and 1c could be recognized by the AT1 receptor with an IC50 value of 1.6 ± 0.09 nM and 2.64 ± 0.7 nM, respectively. In vivo anti-hypertension experiments showed that compounds (1a, 1b, 1c, 1e) elicited a significant decrease in SBP and DBP of spontaneous hypertensive rats (SHRs). The antihypertensive effects maintained for 10 h, which indicated that these compounds had a favorable blood pressure-lowering effect. Acute toxicity testing suggested that the LD50 value of compound 1b was 2316.8 mg/kg which was lower than valsartan (LD50 = 307.50 mg/kg) but higher than losartan (LD50 = 2248 mg/kg). So they could be considered as novel anti-hypertension candidates and deserved for further investigation.