RESUMEN
We have developed a new class of progesterone receptor agonists having a tetracyclic dibenzo-oxazepine structure 1. In this paper, the synthesis and structure-activity relationships of this new class are described. This work led to the identification of potent progesterone agonists up to 1 nM activity. Substitution at positions 6, 7 and 1 has proven to be crucial for activity, indicating that probably these positions are involved in important interactions with the receptor.
Asunto(s)
Oxazepinas/química , Oxazepinas/farmacología , Receptores de Progesterona/agonistas , Acetamidas , Sitios de Unión , Fluoroacetatos , Modelos Moleculares , Progesterona/química , Relación Estructura-Actividad , Ácido Trifluoroacético/químicaRESUMEN
Despite intense research over the last 10 years, aided by the availability of X-ray structures of enzyme-inhibitor complexes, only very few truly orally active thrombin inhibitors have been found. We conducted a comprehensive study starting with peptide transition state analogues (TSA). Both hydrophobic nonpeptide analogues as well as hydrophilic peptidic analogues were synthesized. The bioavailability in rats and dogs could be drastically altered depending on the overall charge distribution in the molecule. Compound 27, a tripeptide TSA inhibitor of thrombin, showed an oral bioavailability of 32% in rats and 71% in dogs, elimination half-lives being 58 and 108 min, respectively. The thrombin inhibition constant of compound 27 was 1.1 nM, and in an in vivo arterial flow model, the ED(50) was 5.4 nmol/kg.min, comparable to known non-TSA inhibitors. A molecular design was found that combines antithrombotic efficiency with oral bioavailability at low dosages.