ABSTRACT
The action of the aspartyl protease renin is the rate-limiting initial step of the renin-angiotensin-aldosterone system. Therefore, renin is a particularly promising target for blood pressure as well as onset and progression of cardiovascular and renal diseases. New pyrimidine derivatives 5-14 were designed in an attempt to enhance the renin inhibitory activity of compound 3 identified by our previous fragment-based drug design approach. Introduction of a basic amine essential for interaction with the two aspartic acids in the catalytic site and optimization of the S1/S3 binding elements including an induced-fit structural change of Leu114 ('Leu-in' to 'Leu-out') by a rational structure-based drug design approach led to the discovery of N-(piperidin-3-yl)pyrimidine-5-carboxamide 14, a 65,000-fold more potent renin inhibitor than compound 3. Surprisingly, this remarkable enhancement in the inhibitory activity of compound 14 has been achieved by the overall addition of only seven heavy atoms to compound 3. Compound 14 demonstrated excellent selectivity over other aspartyl proteases and moderate oral bioavailability in rats.
Subject(s)
Drug Design , Piperidines/pharmacology , Protease Inhibitors/pharmacology , Pyrimidines/pharmacology , Renin/antagonists & inhibitors , Animals , Crystallography, X-Ray , Dose-Response Relationship, Drug , Humans , Models, Molecular , Molecular Structure , Piperidines/chemical synthesis , Piperidines/chemistry , Protease Inhibitors/chemical synthesis , Protease Inhibitors/chemistry , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Rats , Rats, Sprague-Dawley , Renin/blood , Structure-Activity RelationshipABSTRACT
As a part of our research for novel potent and orally available acyl-CoA: cholesterol acyltransferase (ACAT) inhibitors that can be used as anti-atherosclerotic agents, we recently reported the discovery of the (4-phenylcoumarine)acetanilide derivative 1. However, compound 1 showed adrenal toxicity in animal models. In order to search for safer ACAT inhibitors that do not have adrenal toxicity, we examined the inhibitory activity of ACAT in human macrophage and adrenal cells. The introduction of a carboxylic acid moiety on the pendant phenyl ring and the adjustment of the lipophilicity led to the discovery of (2E)-3-[7-chloro-3-[2-[[4-fluoro-2-(trifluoromethyl)phenyl]amino]-2-oxoethyl]-6-methyl-2-oxo-2H-chromen-4-yl]phenyl]acrylic acid (21e), which showed potent ACAT inhibitory activity in macrophages and a selectivity of around 30-fold over adrenal cells. In addition, compound 21e showed high adrenal safety in guinea pigs.
Subject(s)
Acetanilides/chemistry , Adrenal Cortex/drug effects , Anticholesteremic Agents/toxicity , Carboxylic Acids/chemistry , Coumarins/chemistry , Enzyme Inhibitors/toxicity , Sterol O-Acyltransferase/antagonists & inhibitors , Acetanilides/chemical synthesis , Acetanilides/toxicity , Acyl Coenzyme A/metabolism , Administration, Oral , Animals , Anticholesteremic Agents/chemical synthesis , Anticholesteremic Agents/chemistry , Cell Line , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Guinea Pigs , Humans , Models, Animal , Rabbits , Sterol O-Acyltransferase/metabolismABSTRACT
Acyl-CoA: cholesterol acyltransferase (ACAT) is an intracellular enzyme that catalyzes cholesterol esterification. ACAT inhibitors are expected to be potent therapeutic agents for the treatment of atherosclerosis. A series of potent ACAT inhibitors based on an (4-phenylcoumarin)acetanilide scaffold was identified. Evaluation of the structure-activity relationships of a substituent on this scaffold, with an emphasis on improving the pharmacokinetic profile led to the discovery of 2-[7-chloro-4-(3-chlorophenyl)-6-methyl-2-oxo-2H-chromen-3-yl]-N-[4-chloro-2-(trifluoromethyl)phenyl]acetamide (23), which exhibited potent ACAT inhibitory activity (IC50=12 nM) and good pharmacokinetic profile in mice. Compound 23 also showed regressive effects on atherosclerotic plaques in apolipoprotein (apo)E knock out (KO) mice at a dose of 0.3 mg/kg per os (p.o.).
