Discovery of a Potent and Orally Bioavailable Cyclophilin Inhibitor Derived from the Sanglifehrin Macrocycle.

Cyclophilins are a family of peptidyl-prolyl isomerases that are implicated in a wide range of diseases including hepatitis C. Our aim was to discover through total synthesis an orally bioavailable, non-immunosuppressive cyclophilin (Cyp) inhibitor with potent anti-hepatitis C virus (HCV) activity that could serve as part of an all oral antiviral combination therapy. An initial lead 2 derived from the sanglifehrin A macrocycle was optimized using structure based design to produce a potent and orally bioavailable inhibitor 3.

Discovery of Potent Cyclophilin Inhibitors Based on the Structural Simplification of Sanglifehrin A.

Cyclophilin inhibition has been a target for the treatment of hepatitis C and other diseases, but the generation of potent, drug-like molecules through chemical synthesis has been challenging. In this study, a set of macrocyclic cyclophilin inhibitors was synthesized based on the core structure of the natural product sanglifehrin A. Initial compound optimization identified the valine-m-tyrosine-piperazic acid tripeptide (Val-m-Tyr-Pip) in the sanglifehrin core, stereocenters at C14 and C15, and the hydroxyl group of the m-tyrosine (m-Tyr) residue as key contributors to compound potency.

Identification of clinical candidates from the benzazepine class of histamine H3 receptor antagonists.

This Letter describes the discovery of GSK189254 and GSK239512 that were progressed as clinical candidates to explore the potential of H3 receptor antagonists as novel therapies for the treatment of Alzheimer's disease and other dementias. By carefully controlling the physicochemical properties of the benzazepine series and through the implementation of an aggressive and innovative screening strategy that employed high throughput in vivo assays to efficiently triage compounds, the medicinal chemistry effort was able to rapidly progress the benzazepine class of H3 antagonists through to the identification of clinical candidates with robust in vivo efficacy and excellent developability properties.

The discovery of the benzazepine class of histamine H3 receptor antagonists.

This Letter describes the discovery of a novel series of H3 receptor antagonists. The initial medicinal chemistry strategy focused on deconstructing and simplifying an early screening hit which rapidly led to the discovery of a novel series of H3 receptor antagonists based on the benzazepine core. Employing an H3 driven pharmacodynamic model, the series was then further optimised through to a lead compound that showed robust in vivo functional activity and possessed overall excellent developability properties.

Identification of 2-oxo-N-(phenylmethyl)-4-imidazolidinecarboxamide antagonists of the P2X(7) receptor.

A backup molecule to compound 2 was sought by targeting the most likely metabolically vulnerable site in this molecule. Compound 18 was subsequently identified as a potent P2X(7) antagonist with very low in vivo clearance and high oral bioavailability in all species examined. Some evidence to support the role of P2X(7) in the etiology of pain is also presented.

Discovery and structure-activity relationships of a series of pyroglutamic acid amide antagonists of the P2X7 receptor.

A computational lead-hopping exercise identified compound 4 as a structurally distinct P2X(7) receptor antagonist. Structure-activity relationships (SAR) of a series of pyroglutamic acid amide analogues of 4 were investigated and compound 31 was identified as a potent P2X(7) antagonist with excellent in vivo activity in animal models of pain, and a profile suitable for progression to clinical studies.

Structure-activity relationships and in vivo activity of (1H-pyrazol-4-yl)acetamide antagonists of the P2X(7) receptor.

Structure-activity relationships (SAR) of analogues of lead compound 1 were investigated and compound 16 was selected for further study in animal models of pain. Compound 16 was shown to be a potent antihyperalgesic agent in both the rat acute complete Freund's adjuvant (CFA) model of inflammatory pain [Iadarola, M. J.

Mechanism of action of species-selective P2X(7) receptor antagonists.

Background And Purpose: AZ11645373 and N-{2-methyl-5-[(1R, 5S)-9-oxa-3,7-diazabicyclo[3.3.1]non-3-ylcarbonyl]phenyl}-2-tricyclo[3.

Aryl sulphonyl amides as potent agonists of the growth hormone secretagogue (ghrelin) receptor.

As part of an on-going lead optimisation effort, a cross screening exercise identified an aryl sulphonyl amide hit that was optimised to afford a highly potent series of ghrelin receptor agonists.

The identification of potent, selective and CNS penetrant furan-based inhibitors of B-Raf kinase.

Modification of the potent imidazole-based B-Raf inhibitor SB-590885 resulted in the identification of a series of furan-based derivatives with enhanced CNS penetration. One such compound, SB-699393 (17), was examined in vivo to challenge the hypothesis that selective B-Raf inhibitors may be of value in the treatment of stroke.

Potent achiral agonists of the growth hormone secretagogue (ghrelin) receptor. Part 2: Lead optimisation.

A series of small molecule orally bioavailable ghrelin receptor agonists have been identified through systematic optimisation of a high throughput screening hit.

Potent achiral agonists of the ghrelin (growth hormone secretagogue) receptor. Part I: Lead identification.

High throughput screening combined with efficient datamining and parallel synthesis led to the discovery of a novel series of indolines showing potent in vitro ghrelin receptor agonist activity and acceleration of gastric emptying in rats.

The identification of potent and selective imidazole-based inhibitors of B-Raf kinase.

A novel triarylimidazole derivative, SB-590885 (33), bearing a 2,3-dihydro-1H-inden-1-one oxime substituent has been identified as a potent and extremely selective inhibitor of B-Raf kinase.

(1H-imidazo[4,5-c]pyridin-2-yl)-1,2,5-oxadiazol-3-ylamine derivatives: further optimisation as highly potent and selective MSK-1-inhibitors.

The novel imidazo[4,5-c]pyridine 1,2,5-oxadiazol-3-yl template affords an excellent start point for identification of inhibitors of a number of protein kinases. Here we report on its optimisation for mitogen and stress-activated protein kinase-1 (MSK-1) inhibitory activity, and selectivity over other kinases.

(1H-imidazo[4,5-c]pyridin-2-yl)-1,2,5-oxadiazol-3-ylamine derivatives: a novel class of potent MSK-1-inhibitors.

A novel series of imidazo[4,5-c]pyridines bearing a 1,2,5-oxadiazol-3-ylamine functionality has been developed. These are potent inhibitors of mitogen and stress-activated protein kinase-1.

Rate acceleration of the Baylis-Hillman reaction in polar solvents (water and formamide). Dominant role of hydrogen bonding, not hydrophobic effects, is implicated.

A substantial acceleration of the Baylis-Hillman reaction between cyclohexenone and benzaldehyde has been observed when the reaction is conducted in water. Several different amine catalysts were tested, and as with reactions conducted in the absence of solvent, 3-hydroxyquinuclidine was found to be the optimum catalyst in terms of rate. The reaction has been extended to other aldehyde electrophiles including pivaldehyde.