AT1 receptor ligands: virtual-screening-based design with TOPP descriptors, synthesis, and biological evaluation of pyrrolidine derivatives.

As a continuing effort to establish the structure-activity relationships (SARs) within the series of the angiotensin II antagonists (sartans), a pharmacophoric model was built by using novel TOPP 3D descriptors. Statistical values were satisfactory (PC4: r(2)=0.96, q(2) ((5) (random) (groups))=0.84; SDEP=0.26) and encouraged the synthesis and consequent biological evaluation of a series of new pyrrolidine derivatives. SAR together with a combined 3D quantitative SAR and high-throughput virtual screening showed that the newly synthesized 1-acyl-N-(biphenyl-4-ylmethyl)pyrrolidine-2-carboxamides may represent an interesting starting point for the design of new antihypertensive agents. In particular, biological tests performed on CHO-hAT(1) cells stably expressing the human AT(1) receptor showed that the length of the acyl chain is crucial for the receptor interaction and that the valeric chain is the optimal one.

New NO-releasing pharmacodynamic hybrids of losartan and its active metabolite: design, synthesis, and biopharmacological properties.

In a preliminary work, we reported two NO-sartans, possessing the characteristics of an AT(1) antagonist and a "slow NO donor", obtained by adding NO-donor side chains to losartan 1. The NO release from an NO-sartan should be modulated in order to strengthen the antihypertensive activity of the native drug and to ensure additional effects, such as the antiplatelet and anti-ischemic ones. To obtain a collection of prototypical NO-sartans, showing different rates of NO release, new NO-donor moieties have been linked to 1 or its active metabolite 2 (EXP 3174). Almost all the synthesized compounds exhibited both AT(1)-antagonist and NO-mediated vasorelaxing properties, with a wide range of NO-releasing rates. Further pharmacological investigation on compound 4a showed that it possessed antihypertensive and cardiac antihypertrophic effects similar to those of the reference AT(1)-blocking or ACE-inhibiting drugs. Furthermore, the additional anti-ischemic cardio-protective properties and antiplatelet effects of 4a have been preliminarily investigated.