Dieter Lang

Design and Synthesis of Potent and Selective Azaindole‐Based Rho Kinase (ROCK) Inhibitors

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 inu2005vivo.

Potent and Selective Human Neutrophil Elastase Inhibitors with Novel Equatorial Ring Topology: In Vivo Efficacy of the Polar Pyrimidopyridazine Bay-8040 in a Pulmonary Arterial Hypertension Rat Model.

Human neutrophil elastase (HNE) is a key driver of inflammation in many cardiopulmonary and systemic inflammatory and autoimmune conditions. Overshooting high HNE activity is the consequence of a disrupted protease–antiprotease balance. Accordingly, there has been an intensive search for potent and selective HNE inhibitors with suitable pharmacokinetics that would allowing oral administration in patients. Based on the chemical probe BAY‐678 and the clinical candidate BAY 85‐8501 we explored further ring topologies along the equator of the parent pyrimidinone lead series. Novel ring systems were annulated in the east, yielding imidazolo‐, triazolo‐, and tetrazolopyrimidines in order to ensure additional inhibitor–HNE contacts beyond the S1 and the S2 pocket of HNE. The western annulation of pyridazines led to the polar pyrimidopyridazine BAY‐8040, which combines excellent potency and selectivity with a promising pharmacokinetic profile. In vivo efficacy with regard to decreasing cardiac remodeling and amelioration of cardiac function was shown in a monocrotaline‐induced rat model for pulmonary arterial hypertension. This demonstrated in vivo proof of concept in animals.