Discovery and Lead-Optimization of 4,5-Dihydropyrazoles as Mono-Kinase Selective, Orally Bioavailable and Efficacious Inhibitors of Receptor Interacting Protein 1 (RIP1) Kinase.

RIP1 kinase regulates necroptosis and inflammation and may play an important role in contributing to a variety of human pathologies, including inflammatory and neurological diseases. Currently, RIP1 kinase inhibitors have advanced into early clinical trials for evaluation in inflammatory diseases such as psoriasis, rheumatoid arthritis, and ulcerative colitis and neurological diseases such as amyotrophic lateral sclerosis and Alzheimer's disease. In this paper, we report on the design of potent and highly selective dihydropyrazole (DHP) RIP1 kinase inhibitors starting from a high-throughput screen and the lead-optimization of this series from a lead with minimal rat oral exposure to the identification of dihydropyrazole 77 with good pharmacokinetic profiles in multiple species.

Discovery of a First-in-Class Receptor Interacting Protein 1 (RIP1) Kinase Specific Clinical Candidate (GSK2982772) for the Treatment of Inflammatory Diseases.

RIP1 regulates necroptosis and inflammation and may play an important role in contributing to a variety of human pathologies, including immune-mediated inflammatory diseases. Small-molecule inhibitors of RIP1 kinase that are suitable for advancement into the clinic have yet to be described. Herein, we report our lead optimization of a benzoxazepinone hit from a DNA-encoded library and the discovery and profile of clinical candidate GSK2982772 (compound 5), currently in phase 2a clinical studies for psoriasis, rheumatoid arthritis, and ulcerative colitis.

Cell-Based Selection Expands the Utility of DNA-Encoded Small-Molecule Library Technology to Cell Surface Drug Targets: Identification of Novel Antagonists of the NK3 Tachykinin Receptor.

DNA-encoded small-molecule library technology has recently emerged as a new paradigm for identifying ligands against drug targets. To date, this technology has been used with soluble protein targets that are produced and used in a purified state. Here, we describe a cell-based method for identifying small-molecule ligands from DNA-encoded libraries against integral membrane protein targets.

Crystal structures of human RIP2 kinase catalytic domain complexed with ATP-competitive inhibitors: Foundations for understanding inhibitor selectivity.

Receptor interacting protein 2 (RIP2) is an intracellular kinase and key signaling partner for the pattern recognition receptors NOD1 and NOD2 (nucleotide-binding oligomerization domain-containing proteins 1 and 2). As such, RIP2 represents an attractive target to probe the role of these pathways in disease. In an effort to design potent and selective inhibitors of RIP2 we established a crystallographic system and determined the structure of the RIP2 kinase domain in an apo form and also in complex with multiple inhibitors including AMP-PCP (β,γ-Methyleneadenosine 5'-triphosphate, a non-hydrolysable adenosine triphosphate mimic) and structurally diverse ATP competitive chemotypes identified via a high-throughput screening campaign.

-NITRO--SUBSTITUTED GUANIDINES: A SIMPLE CLASS OF NITRIC OXIDE SYNTHASE INHIBITORS.

A series of N-nitro-N-substituted guanidines has been prepared as potential inhibitors of the human Nitric Oxide Synthase (NOS) isoforms. The reported utility of aminoguanidine and nitroarginine in iNOS inhibition points to a potential similar utility for analogs of nitro-guanidine. The compound library was tested against the three isoforms of Nitric Oxide Synthase (eNOS, iNOS and nNOS).

Phenoxyacetic acids as PPARδ partial agonists: synthesis, optimization, and in vivo efficacy.

A series of phenoxyacetic acids as subtype selective and potent hPPARδ partial agonists is described. Many analogues were readily accessible via a single solution-phase synthetic route which resulted in the rapid identification of key structure-activity relationships (SAR), and the discovery of two potent exemplars which were further evaluated in vivo. Details of the SAR, optimization, and in vivo efficacy of this series are presented herein.

Synthesis and structure-activity relationships of a series of 3-aryl-4-isoxazolecarboxamides as a new class of TGR5 agonists.

A series of 3-aryl-4-isoxazolecarboxamides identified from a high-throughput screening campaign as novel, potent agonists of the human TGR5 G-protein-coupled receptor is described. Many analogues were readily accessible via solution-phase synthesis which resulted in the rapid identification of key structure-activity relationships (SAR), and the discovery of potent exemplars (up to pEC50=9). Details of the SAR and optimization of this series are presented herein.

Parallel synthesis of N-biaryl quinolone carboxylic acids as selective M(1) positive allosteric modulators.

An iterative analog library synthesis approach was employed in the exploration of a quinolone carboxylic acid series of selective M(1) positive allosteric modulators, and strategies for improving potency and plasma free fraction were identified.

Discovery of 3-aryl-4-isoxazolecarboxamides as TGR5 receptor agonists.

A series of 3-aryl-4-isoxazolecarboxamides identified from a high-throughput screening campaign as novel, potent small molecule agonists of the human TGR5 G-protein coupled receptor is described. Subsequent optimization resulted in the rapid identification of potent exemplars 6 and 7 which demonstrated improved GLP-1 secretion in vivo via an intracolonic dose coadministered with glucose challenge in a canine model. These novel TGR5 receptor agonists are potentially useful therapeutics for metabolic disorders such as type II diabetes and its associated complications.

Discovery of GlyT1 inhibitors with improved pharmacokinetic properties.

Glycine transporter 1 (GlyT1) represents a novel target for the treatment of schizophrenia via the potentiation of glutamatergic NMDA receptors. The discovery of 4,4-disubstituted piperidine inhibitors of GlyT1 which exhibit improved pharmacokinetic properties, including oral bioavailability, is discussed.

Challenges in the development of mGluR5 positive allosteric modulators: the discovery of CPPHA.

This Letter describes, for the first time, the synthesis and SAR, developed through an iterative analog library approach, that led to the discovery of the positive allosteric modulator (PAM) of the metabotropic glutamate receptor mGluR5 CPPHA. Binding to a unique allosteric binding site distinct from other mGluR5 PAMs, CPPHA has been the focus of numerous pharmacology studies by several laboratories.

p38 MAP kinase inhibitors. Part 3: SAR on 3,4-dihydropyrimido[4,5-d]pyrimidin-2-ones and 3,4-dihydropyrido[4,3-d]pyrimidin-2-ones.

p38 inhibitors based on 3,4-dihydropyrimido[4,5-d]pyrimidin-2-one and 3,4-dihydropyrido[4,3-d]pyrimidin-2-one platforms were synthesized and preliminary SAR explored. Among the pyrimido-pyrimidones the emergence of two sub-types of analogs-C7-amino-pyrimidines such as 24 and C7-amino-piperidines such as 42-characterized with good p38 inhibition and better off-target profiles in terms of ion channel activities was significant. Representative compound 54 in the pyrido-pyrimidone class was found to be equipotent with corresponding analog in the quinazolinone series.

Acetonitrile/water gas-phase reaction products observed by use of atmospheric pressure chemical ionization: adducts formed with sulfonamides.

Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) are the two most common mass spectrometric ionization methods used in the pharmaceutical industry. However, APCI analysis can sometimes lead to ambiguity in compound characterization and quantitation due to gas-phase reactions occurring between acetonitrile and water in the plasma, and between these plasma-generated compounds and the analyte. During the analysis of various sultams and sulfonamides we observed signals corresponding to m/z [M+44](+) and [M+60](+).

A novel selective positive allosteric modulator of metabotropic glutamate receptor subtype 5 has in vivo activity and antipsychotic-like effects in rat behavioral models.

We found that 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) is a potent and selective positive allosteric modulator of the metabotropic glutamate receptor subtype 5 (mGluR5). In Chinese hamster ovary cells expressing human mGluR5, CDPPB potentiated threshold responses to glutamate in fluorometric Ca2+ assays more than 7-fold with an EC50 value of approximately 27 nM. At 1 microM, CDPPB shifted mGluR5 agonist concentration response curves to glutamate, quisqualate, and (R,S)-3,5-dihydroxyphenylglycine 3- to 9-fold to the left.

Discovery of positive allosteric modulators for the metabotropic glutamate receptor subtype 5 from a series of N-(1,3-diphenyl-1H- pyrazol-5-yl)benzamides that potentiate receptor function in vivo.

This report describes the discovery of the first centrally active allosteric modulators of the metabotropic glutamate receptor subtype 5 (mGluR5). Appropriately substituted N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamides (e.g.

Efficient synthesis of imidazoles from aldehydes and 1,2-diketones using microwave irradiation.

[reaction: see text] A simple, high-yielding synthesis of 2,4,5-trisubstituted imidazoles from 1,2-diketones and aldehydes in the presence of NH(4)OAc is described. Under microwave irradiation, alkyl-, aryl-, and heteroaryl-substituted imidazoles are formed in yields ranging from 80 to 99%. Short syntheses of lepidiline B and trifenagrel illustrate the utility of this approach.

A novel selective allosteric modulator potentiates the activity of native metabotropic glutamate receptor subtype 5 in rat forebrain.

We found that N-[4-chloro-2-[(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]phenyl]-2-hydroxybenzamide (CPPHA), is a potent and selective positive allosteric modulator of the metabotropic glutamate receptor subtype 5 (mGluR5). CPPHA alone had no agonist activity and acted as a selective positive allosteric modulator of human and rat mGluR5. CPPHA potentiated threshold responses to glutamate in fluorometric Ca(2+) assays 7- to 8-fold with EC(50) values in the 400 to 800 nM range, and at 10 microM shifted mGluR5 agonist concentration-response curves to glutamate, quisqualate, and (R,S)-3,5-dihydroxyphenylglycine (DHPG) 4- to 7-fold to the left.

p38MAP kinase inhibitors. Part 1: design and development of a new class of potent and highly selective inhibitors based on 3,4-dihydropyrido[3,2-d]pyrimidone scaffold.

A new class of p38 antagonists based on 3,4-dihydropyrido[3,2,-d]pyrimidine scaffold has been developed. These inhibitors exhibit unprecedented selectivity towards p38 over other very closely related kinases. Compounds 25, 33, and 34 were identified as benchmark analogues for follow-up studies.