Discovery of novel indole derivatives as potent and selective inhibitors of proMMP-9 activation.

Matrix metalloproteinase-9 (MMP-9) is a secreted zinc-dependent endopeptidase that degrades the extracellular matrix and basement membrane of neurons, and then contributes to synaptic plasticity by remodeling the extracellular matrix. Inhibition of MMP-9 activity has therapeutic potential for neurodegenerative diseases such as fragile X syndrome. This paper reports the molecular design, synthesis, and in vitro studies of novel indole derivatives as inhibitors of proMMP-9 activation. High-throughput screening (HTS) of our internal compound library and subsequent merging of hit compounds 1 and 2 provided compound 4 as a bona-fide lead. X-ray structure-based design and subsequent lead optimization led to the discovery of compound 33, a highly potent and selective inhibitor of proMMP-9 activation.

Discovery of ORN0829, a potent dual orexin 1/2 receptor antagonist for the treatment of insomnia.

Here, we present the design, synthesis, and SAR of dual orexin 1 and 2 receptor antagonists, which were optimized by balancing the antagonistic activity for orexin receptors and lipophilicity. Based on the prototype compound 1, ring construction and the insertion of an additional heteroatom into the resulting ring led to the discovery of orexin 1 and 2 receptor antagonists, which were 3-benzoyl-1,3-oxazinane derivatives. Within these derivatives, (-)-3h enabled a high dual orexin receptor antagonistic activity and a low lipophilicity. Compound (-)-3h exhibited potent sleep-promoting effects at a po dose of 1 mg/kg in a rat polysomnogram study, and optimal PK properties with a rapid Tmax and short half-lives in rats and dogs were observed, indicating a predicted human half-life of 0.9-2.0 h. Thus, (-)-3h (ORN0829; investigation code name, TS-142) was selected as a viable candidate and is currently in clinical development for the treatment of insomnia.

Identification of highly selective and potent orexin receptor 1 antagonists derived from a dual orexin receptor 1/2 antagonist based on the structural framework of pyrazoylethylbenzamide.

The design, synthesis, and structure activity relationships of the novel class of pyrazolylethylbenzamide orexin receptor 1-selective antagonists are described. Further derivatization of the prototype dual orexin receptor 1/2 antagonist lead (1) by installing a (S)-methyl group into the ethyl linker moiety between the pyrazole ring and benzamide resulted in an increase of the antagonist potency against orexin receptor 1/2 receptors. Optimization of the benzamide and pyrazole parts of compounds 2 and 9b led to the identification of N-ethyl-5-fluoro-N-{(2S)-1-[5-(4-fluorophenyl)-2H-tetrazol-2-yl]propan-2-yl}-2-(pyrimidin-2-yl)benzamide (24), which exhibited excellent antagonistic activity against orexin receptor 1 with an IC50 of 2.01nM and a 265-fold selectivity for orexin receptor 1 over orexin receptor 2.

Discovery and in vitro and in vivo profiles of N-ethyl-N-[2-[3-(5-fluoro-2-pyridinyl)-1H-pyrazol-1-yl]ethyl]-2-(2H-1,2,3-triazol-2-yl)-benzamide as a novel class of dual orexin receptor antagonist.

Orexins play an important role in sleep/wake regulation, and orexin receptor antagonists are a focus of novel therapy for the treatment of insomnia. We identified 27e (TASP0428980) as a potent dual orexin receptor antagonist through the systematic modification of our original designed lead A. We demonstrated the potent sleep-promoting effects of 27e at ip dose of 3mg/kg in a rat polysomnogram study. 27e exhibited relatively short half-life profiles in rats and dogs. Furthermore, accumulating evidence regarding ADME profiles indicates that the predicted human half-life of 27e should be 1.2-1.4h. These data indicated that 27e has a short-acting hypnotic property, suggesting that 27e might be useful for treating primary insomnia while exhibiting a low risk of next-day residual somnolence. Thus, 27e and its related compounds should be further evaluated to enable advancement to clinical trials.