Aldosterone is a hormone that exerts manifold deleterious effects on the kidneys, blood vessels, and heart which can lead to pathophysiological consequences. Inhibition of the mineralocorticoid receptor (MR) is a proven therapeutic concept for the management of associated diseases. Use of the currently marketed MR antagonists spironolactone and eplerenone is restricted, however, due to a lack of selectivity in spironolactone and the lower potency and efficacy of eplerenone. Several pharmaceutical companies have implemented programs to identify drugs that overcome the known liabilities of steroidal MR antagonists. Herein we disclose an extended SAR exploration starting from cyano-1,4-dihydropyridines that were identified by high-throughput screening. Our efforts led to the identification of a dihydronaphthyridine, BAY 94-8862, which is a potent, selective, and orally available nonsteroidal MR antagonist currently under investigation in a clinical phase II trial.

Background and purpose: Rho-kinase (ROCK) has been implicated in the pathophysiology of altered vasoregulation leading to hypertension. Here we describe the pharmacological characterization of a potent, highly selective and orally active ROCK inhibitor, the derivative of a class of azaindoles, azaindole 1 (6-chloro-Experimental approach: Pharmacological characterization of azaindole 1 was performed with human recombinant ROCK in vitro. Vasodilator activity was determined using isolated vessels in vitro and different animal models in vivo. Key results: This compound inhibited the ROCK-1 and ROCK-2 isoenzymes with IC 50 s of 0.6 and 1.1 nM in an ATPcompetitive manner. Although ATP-competitive, azaindole 1 was inactive against 89 kinases (IC 50 410 mM) and showed only weak activity against an additional 21 different kinases (IC 50 ¼ 1 -10 mM). Only the kinases TRK und FLT3 were inhibited by azaindole 1 in the sub-micromolar range, albeit with IC 50 values of 252 and 303 nM, respectively. In vivo, azaindole 1 lowered blood pressure dose-dependently after i.v. administration in anaesthetized normotensive rats. In conscious normotensive and spontaneously hypertensive rats azaindole 1 induced a dose-dependent decrease in blood pressure after oral administration without inducing a significant reflex increase in heart rate. In anaesthetized dogs, azaindole 1 induced vasodilatation with a moderately elevated heart rate. Conclusions and implications: Azaindole 1 is representative of a new class of selective and potent ROCK inhibitors and is a valuable tool for the elucidation of the role of ROCK in the cardiovascular system.

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Intracellular phosphorylation of cis-4-methylsphingosine was previously shown to result in a metabolically stable compound that accumulates in Swiss 3T3 fibroblasts and mimics the mitogenic effect induced by the short-lived sphingosine metabolite, sphingosine-1-phosphate. In the present study incubation of neuroblastoma B104 cells with cis-4-methylsphingosine (10 microM) also resulted in an intracellular accumulation of its phosphorylated derivative that was, however, associated with the concentration-dependent induction of apoptosis, not observed after treatment with 10 microM of sphingosine-1-phosphate or sphingosine, respectively. In B104 cells, cis-4-methylsphingosine stimulated p38 mitogen-activated protein kinase (p38 MAPK) and simultaneously inhibited extracellular signal-regulated kinase (ERK), whereas sphingosine and sphingosine-1-phosphate only stimulated p38 MAPK without suppression of ERK. Inhibition of cis-4-methylsphingosine phosphorylation reduced both, apoptosis and concurrent regulation of mitogen-activated protein kinases (MAPKs), suggesting that the unusual accumulation of the phosphorylated sphingoid base was responsible for the biological effects. Furthermore, inhibition of p38 MAPK prevented cis-4-methylsphingosine-induced apoptosis, while suppression of the ERK pathway in the presence of sphingosine or sphingosine-1-phosphate resulted in apoptosis, indicating that the simultaneous opposite regulation of the two MAPKs was required for the induction of apoptosis.

Rho kinase plays a pivotal role in several cellular processes such as vasoregulation, making it a suitable target for the treatment of hypertension and related disorders. We discovered a new compound class of Rho kinase (ROCK) inhibitors containing a 7-azaindole hinge-binding scaffold tethered to an aminopyrimidine core. Herein we describe the structure-activity relationships elucidated through biochemical and functional assays. The introduction of suitable substituents at the 3-position of the bicyclic moiety led to an increase in activity, which was required to design compounds with favorable pharmacokinetic profile. Azaindole 32 was identified as a highly selective and orally available ROCK inhibitor able to cause a sustained blood pressure reduction in vivo.