Development of potent and selective Cathepsin C inhibitors free of aortic binding liability by application of a conformational restriction strategy.

Cathepsin C plays a key role in the activation of several degradative enzymes linked to tissue destruction in chronic inflammatory and autoimmune diseases. Therefore, Cathepsin C inhibitors could potentially be effective therapeutics for the treatment of diseases such as chronic obstructive pulmonary disease (COPD) or acute respiratory distress syndrome (ARDS). In our efforts towards the development of a novel series of Cathepsin C inhibitors, we started working around AZD5248 (1), an α-amino acid based scaffold having potential liability of aortic binding. A novel series of amidoacetonitrile based Cathepsin C inhibitors were developed by the application of a conformational restriction strategy on 1. In particular, this work led to the development of a potent and selective Cathepsin C inhibitor 3p, free of aortic binding liability.

Development of 2-aryl substituted quinazolin-4(3H)-one, pyrido[4,3-d]pyrimidin-4(3H)-one and pyrido[2,3-d]pyrimidin-4(3H)-one derivatives as microsomal prostaglandin E(2) synthase-1 inhibitors.

mPGES-1 is inducible terminal synthase acting downstream of COX enzymes in arachidonic acid pathway, regulates the biosynthesis of pro-inflammatory prostaglandin PGE2. Cardiovascular side effect of coxibs and NSAIDs, selective for COX-2 inhibition, stimulated interest in mPGES-1, a therapeutic target with potential to deliver safe and effective anti-inflammatory drugs. The synthesis and structure activity relationship of a series of compounds from 2-aryl substituted quinazolin-4(3H)-one, pyrido[4,3-d]pyrimidin-4(3H)-one and pyrido[2,3-d]pyrimidin-4(3H)-one scaffolds as mPGES-1 inhibitor are discussed. A set of analogs (28, 48, 49) were identified with <10nM potencies in the recombinant human mPGES-1 enzyme and in the A549 cellular assays. These analogs were also found to be potent in the human whole blood assay (<400 nM). Furthermore, the representative compound 48 was shown to be selective with other prostanoid synthases and was able to effectively regulate PGE2 biosynthesis in clinically relevant inflammatory settings, in comparison with celecoxib.

Discovery of benzo[d]imidazo[5,1-b]thiazole as a new class of phosphodiesterase 10A inhibitors.

The design, synthesis and structure activity relationship studies of a series of compounds from benzo[d]imidazo[5,1-b]thiazole scaffold as phosphodiesterase 10A (PDE10A) inhibitors are discussed. Several potent analogs with heteroaromatic substitutions (9a-d) were identified. The anticipated binding mode of these analogs was confirmed by performing the in silico docking experiments. Later, the heteroaromatics were substituted with saturated heteroalkyl groups which provided a tool compound 9e with excellent PDE10A activity, PDE selectivity, CNS penetrability and with favorable pharmacokinetic profile in rats. Furthermore, the compound 9e was shown to be efficacious in the MK-801 induced psychosis model and in the CAR model of psychosis.