Macrocyclic Retinoic Acid Receptor-Related Orphan Receptor C2 Inverse Agonists

Macrocyclic retinoic acid receptor-related orphan receptor C2 (RORC2) inverse agonists have been designed with favorable properties for topical administration. Inspired by the unanticipated bound conformation of an acyclic sulfonamide-based RORC2 ligand from cocrystal structure analysis, macrocyclic linker connections between the halves of the molecule were explored. Further optimization of analogues was accomplished to maximize potency and refine physiochemical properties (MW, lipophilicity) best suited for topical application. Compound 14 demonstrated potent inhibition of interleukin-17A (IL-17A) production by human Th17 cells and in vitro permeation through healthy human skin achieving high total compound concentration in both skin epidermis and dermis layers.

Elucidation of a Sequential Iminium Ion Cascade Reaction Triggered by a Silica Gel-Promoted Aza-Peterson Reaction

In a recent methodological study investigating the synthesis of N-alkoxyazomethine ylides, an unexpected aminal byproduct was generated during our attempt to isolate O-benzyl-N-((trimethylsilyl)methyl)hydroxylamine. After a strategic investigation, silica gel was discovered to be the cause of the byproduct formation. Through the mechanistic insight from control and trapping experiments, we propose the formation of a methaniminium ion via a novel aza-Peterson reaction, which ultimately triggers a sequential iminium ion cascade sequence. Herein, we discuss the elucidation of this cascade reaction mechanism and the constraints for the byproduct formation.

PF-06651600, a Dual JAK3/TEC Family Kinase Inhibitor

PF-06651600 was developed as an irreversible inhibitor of JAK3 with selectivity over the other three JAK isoforms. A high level of selectivity toward JAK3 is achieved by the covalent interaction of PF-06651600 with a unique cysteine residue (Cys-909) in the catalytic domain of JAK3, which is replaced by a serine residue in the other JAK isoforms. Importantly, 10 other kinases in the kinome have a cysteine at the equivalent position of Cys-909 in JAK3. Five of those kinases belong to the TEC kinase family including BTK, BMX, ITK, RLK, and TEC and are also inhibited by PF-06651600. Preclinical data demonstrate that inhibition of the cytolytic function of CD8⁺ T cells and NK cells by PF-06651600 is driven by the inhibition of TEC kinases. On the basis of the underlying pathophysiology of inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease, alopecia areata, and vitiligo, the dual activity of PF-06651600 toward JAK3 and the TEC kinase family may provide a beneficial inhibitory profile for therapeutic intervention.

Aminopyrazole Carboxamide Bruton's Tyrosine Kinase Inhibitors. Irreversible to Reversible Covalent Reactive Group Tuning

Potent covalent inhibitors of Bruton's tyrosine kinase (BTK) based on an aminopyrazole carboxamide scaffold have been identified. Compared to acrylamide-based covalent reactive groups leading to irreversible protein adducts, cyanamide-based reversible-covalent inhibitors provided the highest combined BTK potency and EGFR selectivity. The cyanamide covalent mechanism with BTK was confirmed through enzyme kinetic, NMR, MS, and X-ray crystallographic studies. The lead cyanamide-based inhibitors demonstrated excellent kinome selectivity and rat pharmacokinetic properties.

Dual Inhibition of TYK2 and JAK1 for the Treatment of Autoimmune Diseases: Discovery of (( S)-2,2-Difluorocyclopropyl)((1 R,5 S)-3-(2-((1-methyl-1 H-pyrazol-4-yl)amino)pyrimidin-4-yl)-3,8-diazabicyclo[3.2.1]octan-8-yl)methanone (PF-06700841)

Cytokine signaling is an important characteristic of autoimmune diseases. Many pro-inflammatory cytokines signal through the Janus kinase (JAK)/Signal transducer and activator of transcription (STAT) pathway. JAK1 is important for the γ-common chain cytokines, interleukin (IL)-6, and type-I interferon (IFN) family, while TYK2 in addition to type-I IFN signaling also plays a role in IL-23 and IL-12 signaling. Intervention with monoclonal antibodies (mAbs) or JAK1 inhibitors has demonstrated efficacy in Phase III psoriasis, psoriatic arthritis, inflammatory bowel disease, and rheumatoid arthritis studies, leading to multiple drug approvals. We hypothesized that a dual JAK1/TYK2 inhibitor will provide additional efficacy, while managing risk by optimizing selectivity against JAK2 driven hematopoietic changes. Our program began with a conformationally constrained piperazinyl-pyrimidine Type 1 ATP site inhibitor, subsequent work led to the discovery of PF-06700841 (compound 23), which is in Phase II clinical development (NCT02969018, NCT02958865, NCT03395184, and NCT02974868).

A Parallel Approach to 7-(Hetero)arylpyrazolo[1,5- a]pyrimidin-5-ones

A modular, two-pot assembly of 7-arylpyrazolo[1,5- a]pyrimidones from aryl/heteroaryl halides and aminopyrazoles in library format was developed. Sonogashira coupling of aryl bromides with triethyl orthopropiolate, followed by in situ orthoester hydrolysis, provides access to β-aryl ynoates, which undergo regioselective cyclocondensation with aminopyrazoles. The ability to vary the C7 vector of 7-arylpyrazolo[1,5- a]pyrimidones in two steps using readily available (hetero)aryl halides significantly enhances synthetic access to this challenging vector.

Discovery of a JAK3-Selective Inhibitor: Functional Differentiation of JAK3-Selective Inhibition over pan-JAK or JAK1-Selective Inhibition

PF-06651600, a newly discovered potent JAK3-selective inhibitor, is highly efficacious at inhibiting γc cytokine signaling, which is dependent on both JAK1 and JAK3. PF-06651600 allowed the comparison of JAK3-selective inhibition to pan-JAK or JAK1-selective inhibition, in relevant immune cells to a level that could not be achieved previously without such potency and selectivity. In vitro, PF-06651600 inhibits Th1 and Th17 cell differentiation and function, and in vivo it reduces disease pathology in rat adjuvant-induced arthritis as well as in mouse experimental autoimmune encephalomyelitis models. Importantly, by sparing JAK1 function, PF-06651600 selectively targets γc cytokine pathways while preserving JAK1-dependent anti-inflammatory signaling such as the IL-10 suppressive functions following LPS treatment in macrophages and the suppression of TNFα and IL-1β production in IL-27-primed macrophages. Thus, JAK3-selective inhibition differentiates from pan-JAK or JAK1 inhibition in various immune cellular responses, which could potentially translate to advantageous clinical outcomes in inflammatory and autoimmune diseases.

MEK inhibitors: a patent review 2008 - 2010

INTRODUCTION

MAPK/extracellular signal-regulated kinase (MEK) inhibitors target the Ras/Raf/MEK/ERK signaling pathway, which is important in cell growth, differentiation and development. The pathway has been implicated in the progression of a variety of diseases, in particular cancer, as well as in immune and inflammatory diseases such as rheumatoid arthritis, organ transplant rejection, septic shock, asthma and viral infection.

AREAS COVERED

A comprehensive review of the patent literature (2008 - 2010) covering MEK inhibitors and combinations thereof is provided in this paper.

EXPERT OPINION

The first MEK inhibitor was described in the literature in 1995, and several companies are still active in the research and development of MEK inhibitors for various disease states. The emerging role of MEK inhibitors in disease has prompted further investigations of this important target. The combination of MEK inhibitors with other agents/therapies in the treatment of diseases, particularly cancer, is a key development in the field.

Discovery of an Oral Potent Selective Inhibitor of Hematopoietic Prostaglandin D Synthase (HPGDS)

Hematopoietic prostaglandin D synthase (HPGDS) is primarly expressed in mast cells, antigen-presenting cells, and Th-2 cells. HPGDS converts PGH2 into PGD2, a mediator thought to play a pivotal role in airway allergy and inflammatory processes. In this letter, we report the discovery of an orally potent and selective inhibitor of HPGDS that reduces the antigen-induced response in allergic sheep.

Design, synthesis, and biological evaluation of pyrazinones containing novel P1 needles as inhibitors of TF/VIIa

Herein is described the design, synthesis, and enzymatic activity of a series of substituted pyrazinones as inhibitors of the TF/VIIa complex. These inhibitors were designed to explore replacement and variation of the P1 amidine described previously [J. Med. Chem.2003, 46, 4050]. The P1 needle replacements were selected based upon their reduced basicity compared to the parent phenyl amidine (pKa approximately 12). A contributing factor towards the oral bioavailability of a compound is the ionization state of the compound in the intestinal tract. The desired outcome of the study was to identify an orally bioavailable TF-VIIa inhibitor.

Novel tetrahydro-β-carboline-1-carboxylic acids as inhibitors of mitogen activated protein kinase-activated protein kinase 2 (MK-2)

A structure-activity relationship study was conducted on a series of tetrahydro-beta-carboline-1-carboxylic acid analogs in order to identify the key functionality responsible for activity against the mitogen-activated protein kinase-activated protein kinase 2 enzyme (MK-2). The compounds were further evaluated for their ability to inhibit TNFalpha production in U937 cells and in vivo. These compounds represent a novel structural class of compounds capable of inhibiting MK-2 with remarkable selectivity.

Design, synthesis and biological evaluation of nonpeptide integrin antagonists

Recent studies demonstrated that peptide and antibody antagonists of integrin alpha v beta 3 block angiogenesis and tumor growth. In this article, the design, synthesis and biological evaluation of a series of nitroaryl ether-based, nonpeptide mimetics are described. The design of these compounds was based on Merck's arylether/alpha-aminoacid/guanidine framework and incorporates a novel nitroaryl system. The synthesized mimetics were tested against a variety of integrins (alpha v beta 3, alpha IIb beta 3, and alpha v beta 5) in order to determine their binding selectivity and ability to inhibit cell adhesion. Selected compounds were also tested for their ability to inhibit angiogenesis in vivo in the CAM (chick chorioallantoic membrane) assay. From the generated compound library, compounds 16 and 19 proved to be potent and selective inhibitors of alpha IIb beta 3 (IC50 = 14 nM) whereas compound 11 showed excellent in vivo inhibition of angiogenesis (at 30 micrograms/embryo).