Pyrrolopyridine inhibitors of mitogen-activated protein kinase-activated protein kinase 2 (MK-2).

A new class of potent kinase inhibitors selective for mitogen-activated protein kinase-activated protein kinase 2 (MAPKAP-K2 or MK-2) for the treatment of rheumatoid arthritis has been prepared and evaluated. These inhibitors have IC50 values as low as 10 nM against the target and have good selectivity profiles against a number of kinases including CDK2, ERK, JNK, and p38. These MK-2 inhibitors have been shown to suppress TNFalpha production in U397 cells and to be efficacious in an acute inflammation model. The structure-activity relationships of this series, the selectivity for MK-2 and their activity in both in vitro and in vivo models are discussed. The observed selectivity is discussed with the aid of an MK-2/inhibitor crystal structure.

Discovery of potent, nonsystemic apical sodium-codependent bile acid transporter inhibitors (Part 1).

Elevated plasma levels of low-density lipoprotein (LDL) cholesterol are a major risk factor for atherosclerosis leading to coronary artery disease (CAD), which remains the main cause of mortality in Western society. We believe that by preventing the reabsorption of bile acids, a minimally absorbed apical sodium-codependent bile acid transporter (ASBT) inhibitor would lower the serum cholesterol without the potential systemic side effects of an absorbed drug. A series of novel benzothiepines (3R,3R'-2,3,4,5-tetrahydro-5-aryl-1-benzothiepin-4-ol 1,1-dioxides) were synthesized and tested for their ability to inhibit the apical sodium dependent bile acid transport (ASBT)-mediated uptake of [(14)C]taurocholate (TC) in H14 cells. A 3R,4R,5R/3S,4S,5S racemate was found to have greater potency than the other three possible racemates. Addition of electron-donating groups such as a dimethylamino substituent at the 7 position greatly enhanced potency, and incorporation of a long-chain quaternary ammonium substituent on the 5-phenyl ring was useful in minimizing systemic exposure of this locally active ASBT inhibitor while also increasing water solubility and maintaining potency. The reported results describe the synthesis and SAR development of this benzothiepine class of ASBT inhibitors resulting in an 6000-fold improvement in ASBT inhibition with desired minimal systemic exposure of this locally acting drug candidate.

Discovery of potent, nonsystemic apical sodium-codependent bile acid transporter inhibitors (Part 2).

In the preceding paper several compounds were reported as potent apical sodium-codependent bile acid transporter (ASBT) inhibitors. Since the primary site for active bile acid reabsorption is via ASBT, which is localized on the luminal surface of the distal ileum, we reasoned that a nonsystemic inhibitor would be desirable to minimize or eliminate potential systemic side effects of an absorbed drug. To ensure bioequivalency and product stability, it was also essential that we identify a nonhygroscopic inhibitor in its most stable crystalline form. A series of benzothiepines were prepared to refine the structure-activity relationship of the substituted phenyl ring at the 5-position of benzothiepine ring and to identify potent, crystalline, nonhygroscopic, and efficacious ASBT inhibitors with low systemic exposure.

Discovery of (3S,3aR)-2-(3-chloro-4-cyanophenyl)-3-cyclopentyl-3,3a,4,5-tetrahydro-2H-benzo[g]indazole-7-carboxylic acid (PF-3882845), an orally efficacious mineralocorticoid receptor (MR) antagonist for hypertension and nephropathy.

We have discovered a novel class of nonsteroidal pyrazoline antagonists of the mineralocorticoid receptor (MR) that show excellent potency and selectivity against other nuclear receptors. Early analogues were poorly soluble and had a propensity to inhibit the hERG channel. Remarkably, both of these challenges were overcome by incorporation of a single carboxylate moiety. Structural modification of carboxylate-containing lead R-4g with a wide range of substituents at each position of the pyrazoline ring resulted in R-12o, which shows excellent activity against MR and reasonable pharmacokinetic profile. Introduction of conformational restriction led to a novel series characterized by exquisite potency and favorable steroid receptor selectivity and pharmacokinetic profile. Oral dosing of 3S,3aR-27d (PF-3882845) in the Dahl salt sensitive preclinical model of salt-induced hypertension and nephropathy showed blood pressure attenuation significantly greater than that with eplerenone, reduction in urinary albumin, and renal protection. As a result of these findings, 3S,3aR-27d was advanced to clinical studies.

Design, synthesis, and biological evaluation of pyrazinones containing novel P1 needles as inhibitors of TF/VIIa.

Herein is described the design, synthesis, and enzymatic activity of a series of substituted pyrazinones as inhibitors of the TF/VIIa complex. These inhibitors were designed to explore replacement and variation of the P1 amidine described previously [J. Med. Chem.2003, 46, 4050]. The P1 needle replacements were selected based upon their reduced basicity compared to the parent phenyl amidine (pKa approximately 12). A contributing factor towards the oral bioavailability of a compound is the ionization state of the compound in the intestinal tract. The desired outcome of the study was to identify an orally bioavailable TF-VIIa inhibitor.

Novel tetrahydro-beta-carboline-1-carboxylic acids as inhibitors of mitogen activated protein kinase-activated protein kinase 2 (MK-2).

A structure-activity relationship study was conducted on a series of tetrahydro-beta-carboline-1-carboxylic acid analogs in order to identify the key functionality responsible for activity against the mitogen-activated protein kinase-activated protein kinase 2 enzyme (MK-2). The compounds were further evaluated for their ability to inhibit TNFalpha production in U937 cells and in vivo. These compounds represent a novel structural class of compounds capable of inhibiting MK-2 with remarkable selectivity.

A novel class of apical sodium co-dependent bile acid transporter inhibitors: the 1,2-benzothiazepines.

A series of 5-aryl-3,3-dibutyl-7-(dimethylamino)-1,2-benzothiazepin-4-ol 1,1-dioxides were prepared and were found to inhibit the apical sodium co-dependent bile acid transporter (ASBT) for the potential treatment for hyperlipidemia. Several 1,2-benzothiazepines exhibited low nanomolar in vitro activity. The synthesis and initial in vitro potency data is presented for this novel class of compounds.