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Tuesday, 31 May 2016

CCT 245737

CCT 245737

M.Wt: 379.34
Formula: C16H16F3N7O
2-​Pyrazinecarbonitrile​, 5-​[[4-​[[(2R)​-​2-​morpholinylmethyl]​amino]​-​5-​(trifluoromethyl)​-​2-​pyridinyl]​amino]​-
IND Filed, Sareum FOR CANCER

Synthesis, Exclusive by worlddrugtracker

5-[[4-[[morpholin-2-yl]methylamino]-5- (trifluoromethyl)-2-pyridyl]amino]pyrazine-2-carbonitrile compounds (referred to herein as "TFM compounds") which, inter alia, inhibit Checkpoint Kinase 1 (CHK1) kinase function. The present invention also pertains to pharmaceutical compositions comprising such compounds, and the use of such compounds and compositions, both in vitro and in vivo, to inhibit CHK1 kinase function, and in the treatment of diseases and conditions that are mediated by CHK1 , that are ameliorated by the inhibition of CHK1 kinase function, etc., including proliferative conditions such as cancer, etc., optionally in combination with another agent, for example, (a) a DNA topoisomerase I or II inhibitor; (b) a DNA damaging agent; (c) an antimetabolite or a thymidylate synthase (TS) inhibitor; (d) a microtubule targeted agent; (e) ionising radiation; (f) an inhibitor of a mitosis regulator or a mitotic checkpoint regulator; (g) an inhibitor of a DNA damage signal transducer; or (h) an inhibitor of a DNA damage repair enzyme.
Checkpoint Kinase 1 (CHK1)
Progression through the cell division cycle is a tightly regulated process and is monitored at several positions known as cell cycle checkpoints (see, e.g., Weinert and Hartwell,
1989; Bartek and Lukas, 2003). These checkpoints are found in all four stages of the cell cycle; G1 , S (DNA replication), G2 and M (Mitosis) and they ensure that key events which control the fidelity of DNA replication and cell division are completed correctly. Cell cycle checkpoints are activated by a number of stimuli, including DNA damage and DNA errors caused by defective replication. When this occurs, the cell cycle will arrest, allowing time for either DNA repair to occur or, if the damage is too severe, for activation of cellular processes leading to controlled cell death.
All cancers, by definition, have some form of aberrant cell division cycle. Frequently, the cancer cells possess one or more defective cell cycle checkpoints, or harbour defects in a particular DNA repair pathway. These cells are therefore often more dependent on the remaining cell cycle checkpoints and repair pathways, compared to non-cancerous cells (where all checkpoints and DNA repair pathways are intact). The response of cancer cells to DNA damage is frequently a critical determinant of whether they continue to proliferate or activate cell death processes and die. For example, tumour cells that contain a mutant form(s) of the tumour suppressor p53 are defective in the G1 DNA damage checkpoint. Thus inhibitors of the G2 or S-phase checkpoints are expected to further impair the ability of the tumour cell to repair damaged DNA. Many known cancer treatments cause DNA damage by either physically modifying the cell's DNA or disrupting vital cellular processes that can affect the fidelity of DNA replication and cell division, such as DNA metabolism, DNA synthesis, DNA transcription and microtubule spindle formation. Such treatments include for example, radiotherapy, which causes DNA strand breaks, and a variety of chemotherapeutic agents including topoisomerase inhibitors, antimetabolites, DNA-alkylating agents, and platinum- containing cytotoxic drugs. A significant limitation to these genotoxic treatments is drug resistance. One of the most important mechanisms leading to this resistance is attributed to activation of cell cycle checkpoints, giving the tumour cell time to repair damaged DNA. By abrogating a particular cell cycle checkpoint, or inhibiting a particular form of DNA repair, it may therefore be possible to circumvent tumour cell resistance to the genotoxic agents and augment tumour cell death induced by DNA damage, thus increasing the therapeutic index of these cancer treatments.
CHK1 is a serine/threonine kinase involved in regulating cell cycle checkpoint signals that are activated in response to DNA damage and errors in DNA caused by defective replication (see, e.g., Bartek and Lukas, 2003). CHK1 transduces these signals through phosphorylation of substrates involved in a number of cellular activities including cell cycle arrest and DNA repair. Two key substrates of CHK1 are the Cdc25A and Cdc25C phosphatases that dephosphorylate CDK1 leading to its activation, which is a
requirement for exit from G2 into mitosis (M phase) (see, e.g., Sanchez et al., 1997). Phosphorylation of Cdc25C and the related Cdc25A by CHK1 blocks their ability to activate CDK1 , thus preventing the cell from exiting G2 into M phase. The role of CHK1 in the DNA damage-induced G2 cell cycle checkpoint has been demonstrated in a number of studies where CHK1 function has been knocked out (see, e.g., Liu et ai, 2000; Zhao et al., 2002; Zachos et al., 2003).
The reliance of the DNA damage-induced G2 checkpoint upon CHK1 provides one example of a therapeutic strategy for cancer treatment, involving targeted inhibition of CHK1. Upon DNA damage, the p53 tumour suppressor protein is stabilised and activated to give a p53-dependent G1 arrest, leading to apoptosis or DNA repair (Balaint and Vousden, 2001). Over half of all cancers are functionally defective for p53, which can make them resistant to genotoxic cancer treatments such as ionising radiation (IR) and certain forms of chemotherapy (see, e.g., Greenblatt et al., 1994; Carson and Lois, 1995). These p53 deficient cells fail to arrest at the G1 checkpoint or undergo apoptosis or DNA repair, and consequently may be more reliant on the G2 checkpoint for viability and replication fidelity. Therefore abrogation of the G2 checkpoint through inhibition of the CHK1 kinase function may selectively sensitise p53 deficient cancer cells to genotoxic cancer therapies, and this has been demonstrated (see, e.g., Wang et al., 1996; Dixon and Norbury, 2002). In addition, CHK1 has also been shown to be involved in S phase cell cycle checkpoints and DNA repair by homologous recombination. Thus, inhibition of CHK1 kinase in those cancers that are reliant on these processes after DNA damage, may provide additional therapeutic strategies for the treatment of cancers using CHK1 inhibitors (see, e.g., Sorensen et al., 2005). Furthermore, certain cancers may exhibit replicative stress due to high levels of endogenous DNA damage (see, e.g., Cavalier et al., 2009; Brooks et al., 2012) or through elevated replication driven by oncogenes, for example amplified or overexpressed MYC genes (see, e.g., Di Micco et al. 2006; Cole et al., 2011 ; Murga et al. 2011). Such cancers may exhibit elevated signalling through CHK1 kinase (see, e.g., Hoglund et al., 2011). Inhibition of CHK1 kinase in those cancers that are reliant on these processes, may provide additional therapeutic strategies for the treatment of cancers using CHK1 inhibitors (see, e.g., Cole et al., 2011 ; Davies et al., 2011 ; Ferrao et al., 2011).
Several kinase enzymes are important in the control of the cell growth and replication cycle. These enzymes may drive progression through the cell cycle, or alternatively can act as regulators at specific checkpoints that ensure the integrity of DNA replication through sensing DNA-damage and initiating repair, while halting the cell cycle. Many tumours are deficient in early phase DNA-damage checkpoints, due to mutation or deletion in the p53 pathway, and thus become dependent on the later S and G2/M checkpoints for DNA repair. This provides an opportunity to selectively target tumour cells to enhance the efficacy of ionising radiation or widely used DNA-damaging cancer chemotherapies. Inhibitors of the checkpoint kinase CHK1 are of particular interest for combination with genotoxic agents. In collaboration with Professor Michelle Garrett (University of Kent, previously at The Institute of Cancer Research) and Sareum (Cambridge) we used structure-based design to optimise the biological activities and pharmaceutical properties of hits identified through fragment-based screening against the cell cycle kinase CHK1, leading to the oral clinical candidate CCT245737. The candidate potentiates the efficacy of standard chemotherapy in models of non-small cell lung, pancreatic and colon cancer. In collaboration with colleagues at The Institute of Cancer Research (Professor Louis Chesler, Dr Simon Robinson and Professor Sue Eccles) and Newcastle University (Professor Neil Perkins), we have shown that our selective CHK1 inhibitor has efficacy as a single agent in models of tumours with high replication stress, including neuroblastoma and lymphoma.
The checkpoint kinase CHK2 has a distinct but less well characterised biological role to that of CHK1. Selective inhibitors are valuable as pharmacological tools to explore the biological consequences of CHK2 inhibition in cancer cells. In collaboration with Professor Michelle Garrett (University of Kent, previously at The Institute of Cancer Research), we have used structure-based and ligand-based approaches to discover selective inhibitors of CHK2. We showed that selective CHK2 inhibition has a very different outcome to selective CHK1 inhibition. Notably, while CHK2 inhibition did not potentiate the effect of DNA-damaging chemotherapy, it did sensitize cancer cells to the effects of PARP inhibitors that compromise DNA repair.
 as a pale-yellow amorphous solid.
1H NMR ((CD3)2SO, 500 MHz) δ 10.7 (br s, 1H), 9.10 (d, J = 1.4 Hz, 1H), 8.77 (d, J = 1.4 Hz, 1H), 8.20 (s, 1H), 7.19 (s, 1H), 6.32 (br t, J = 5.5 Hz, 1H), 3.75 (br d, J = 11.0 Hz, 1H), 3.64–3.59 (m, 1H), 3.43 (ddd, J = 10.7, 10.7, and 3.4 Hz, 1H), 3.22 (m, 2H), 2.82 (dd, J = 12.1 and 2.1 Hz, 1H), 2.67–2.59 (m, 2H), 2.42 (dd, J = 12.1 and 10.0 Hz, 1H).
13C NMR ((CD3)2SO, 125 MHz) δ 155.7, 151.9, 151.6, 147.2, 145.9 (q, JCF = 6.3 Hz), 136.8, 124.8 (q, JCF= 270.9 Hz), 118.9, 117.1, 104.4 (q, JCF = 30.0 Hz), 93.2, 73.6, 67.2, 48.9, 45.4, 44.9.
LCMS (3.5 min) tR = 1.17 min; m/z (ESI+) 380 (M + H+).
HRMS m/z calcd for C16H17F3N7O (M + H) 380.1441, found 380.1438.


WO 2013171470
http://www.google.com/patents/WO2013171470A1?cl=enSynthesis 1 D
carbonitrile (Compound 1)
Figure imgf000044_0002
A solution of (S)-tert-butyl 2-((2-(5-cyanopyrazin-2-ylamino)-5-(trifluoromethyl)pyridin-4- ylamino)methyl)morpholine-4-carboxylate (1.09 g, 2.273 mmol) in dichloromethane (8 mL) was added dropwise over 10 minutes to a solution of trifluoroacetic acid (52.7 mL, 709 mmol) and tnisopropylsilane (2.61 mL, 12.73 mmol) in dry dichloromethane (227 mL) at room temperature. After stirring for 30 minutes, the mixture was concentrated in vacuo. The concentrate was resuspended in dichloromethane (200 mL) and
concentrated in vacuo, then resuspended in toluene (100 mL) and concentrated.
The above procedure was performed in triplicate (starting each time with 1.09 g (S)-tert- butyl 2-((2-(5-cyanopyrazin-2-ylamino)-5-(trifluoromethyl)pyridin-4- ylamino)methyl)morpholine-4-carboxylate) and the three portions of crude product so generated were combined for purification by ion exchange chromatography on 2 x 20 g Biotage NH2 Isolute columns, eluting with methanol. The eluant was concentrated and 10% methanol in diethyl ether (25 mL) was added. The resulting solid was filtered, washed with diethyl ether (30 mL), and dried in vacuo to give the title compound as a light straw coloured powder (2.30 g, 89%). H NMR (500 MHz, CD3OD) δ 2.62 (1 H, J = 12, 10 Hz), 2.78-2.84 (2H, m), 2.95 (1 H, dd, J = 12, 2 Hz), 3.27-3.38 (2H, m), 3.63 (1 H, ddd, J = 14, 9.5, 3 Hz), 3.73-3.78 (1 H, m), 3.91 (1 H, ddd, J = 11 , 4, 2 Hz), 7.26 (1 H, s), 8.18 (1 H, s), 8.63 (1 H, s), 9.01 (1 H, s).
LC-MS (Agilent 4 min) Rt 1.22 min; m/z (ESI) 380 [M+H+]. Optical rotation [a]D 24 = +7.0 (c 1.0, DMF).
Synthesis 2B
(R)-tert- Butyl 2-((2-chloro-5-(trifluoromethyl)pyridin-4-ylamino)methyl)morpholine-
Figure imgf000046_0001
To a solution of 2-chloro-5-(trifluoromethyl)pyridin-4-amine (1 g, 5.09 mmol) in
dimethylformamide (32.6 mL) was added sodium hydride (60% by wt in oil; 0.407 g, 10.18 mmol) portionwise at room temperature followed by stirring for 10 minutes at 80°C. (S)- tert-Butyl 2-(tosyloxymethyl)morpholine-4-carboxylate (2.268 g, 6.1 1 mmol) was then added portionwise and the reaction mixture was stirred at 80°C for 2.5 hours. After cooling, the mixture was partitioned between saturated aqueous sodium
hydrogencarbonate solution (30 mL), water (100 mL) and ethyl acetate (30 mL). The organic layer was separated and the aqueous layer was further extracted with ethyl acetate (2 x 30 mL). The combined organic layers were washed with brine (2 x 70 mL), dried over magnesium sulfate, filtered, concentrated and dried thoroughly in vacuo. The crude material was purified by column chromatography on a 90 g Thomson SingleStep column, eluting with an isocratic mix of 2.5% diethyl ether / 2.5% ethyl acetate in dichloromethane, to give the title compound as a clear gum that later crystallised to give a white powder (1.47 g, 73%). H NMR (500 MHz, CDCI3) δ 1.48 (9H, s), 2.71-2.83 (1 H, m), 2.92-3.05 (1 H, m), 3.18- 3.23 (1 H, m), 3.33-3.37 (1 H, m), 3.56-3.61 (1 H, m), 3.66-3.71 (1 H, m), 3.80-4.07 (3H, m), 5.32 (1 H, broad s), 6.61 (1 H, s), 8.24 (1 H, s). LC-MS (Agilent 4 min) Rt 3.04 min; m/z (ESI) 396 [MH+]. Svnthesis 2C
(R)-tert-Butyl 2-((2-(5-cyanopyrazin-2-ylamino)-5-(trifluoromethyl)pyridin-4-
Figure imgf000047_0001
(R)-tert-Butyl 2-((2-chloro-5-(trifluoromethyl)pyridin-4-ylamino)methyl)morpholine-4- carboxylate (1.44 g, 3.64 mmol), 2-amino-5-cyanopyrazine (0.612 g, 5.09 mmol, 1.4 eq.), tris(dibenzylideneacetone)dipalladium(0) (0.267 g, 0.291 mmol, 0.08 eq.), rac-2,2'- bis(diphenylphosphino)-1 ,1 '-binaphthyl (0.362 g, 0.582 mmol, 0.16 eq.) and caesium carbonate (2.37 g, 7.28 mmol) were suspended in anhydrous dioxane (33 ml_) under argon. Argon was bubbled through the mixture for 30 minutes, after which the mixture was heated to 100°C for 22 hours. The reaction mixture was cooled and diluted with dichloromethane, then absorbed on to silica gel. The pre-absorbed silica gel was added to a 100 g KP-Sil SNAP column which was eluted with 20-50% ethyl acetate in hexanes to give the partially purified product as an orange gum. The crude product was dissolved in dichloromethane and purified by column chromatography on a 90 g SingleStep Thomson column, eluting with 20% ethyl acetate in dichloromethane, to give the title compound (1.19 g, 68%). H NMR (500 MHz, CDCI3) δ 1.50 (9H, s), 2.71-2.88 (1 H, m), 2.93-3.08 (1 H, m), 3.27- 3.32 (1 H, m), 3.40-3.44 (1 H, m), 3.55-3.64 (1 H, m), 3.71-3.77 (1 H, m), 3.82-4.11 (3H, m), 5.33 (1 H, broad s), 7.19 (1 H, s), 8.23 (1 H, s), 8.58 (1 H, s), 8.84 (1 H, s). LC-MS (Agilent 4 min) Rt 2.93 min;m/z (ESI) 480 [MH+].


Abstract Image
Multiparameter optimization of a series of 5-((4-aminopyridin-2-yl)amino)pyrazine-2-carbonitriles resulted in the identification of a potent and selective oral CHK1 preclinical development candidate with in vivo efficacy as a potentiator of deoxyribonucleic acid (DNA) damaging chemotherapy and as a single agent. Cellular mechanism of action assays were used to give an integrated assessment of compound selectivity during optimization resulting in a highly CHK1 selective adenosine triphosphate (ATP) competitive inhibitor. A single substituent vector directed away from the CHK1 kinase active site was unexpectedly found to drive the selective cellular efficacy of the compounds. Both CHK1 potency and off-target human ether-a-go-go-related gene (hERG) ion channel inhibition were dependent on lipophilicity and basicity in this series. Optimization of CHK1 cellular potency and in vivo pharmacokinetic–pharmacodynamic (PK–PD) properties gave a compound with low predicted doses and exposures in humans which mitigated the residual weak in vitro hERG inhibition.

Multiparameter Lead Optimization to Give an Oral Checkpoint Kinase 1 (CHK1) Inhibitor Clinical Candidate: (R)-5-((4-((Morpholin-2-ylmethyl)amino)-5-(trifluoromethyl)pyridin-2-yl)amino)pyrazine-2-carbonitrile (CCT245737)

Cancer Research UK Cancer Therapeutics Unit and Division of Radiotherapy and Imaging, The Institute of Cancer Research, London SM2 5NG, U.K.
§ Sareum Ltd., Cambridge CB22 3FX, U.K.
J. Med. Chem., Article ASAP
DOI: 10.1021/acs.jmedchem.5b01938
Publication Date (Web): May 11, 2016
Copyright © 2016 American Chemical Society
*Phone: +44 2087224000. Fax: +44 2087224126. E-mail: ian.collins@icr.ac.uk.
///////////CCT 245737, IND, PRECLINICAL, Cancer Research Technology Limited, SAREUM

Monday, 30 May 2016

GSK 6853


GSK 6853
CAS  1910124-24-1
C22 H27 N5 O3, 409.48
Benzamide, N-​[2,​3-​dihydro-​1,​3-​dimethyl-​6-​[(2R)​-​2-​methyl-​1-​piperazinyl]​-​2-​oxo-​1H-​benzimidazol-​5-​yl]​-​2-​methoxy-
(R)-N-(1 ,3- dimethyl-6-(2-methylpiperazin-1 -yl)-2-oxo-2,3-dihydro-1 H-benzo[d]imidazol-5-yl)-2- methoxybenzamide
A white solid.
LCMS (high pH): Rt = 0.90 min, [M+H+]+ 410.5.
δΗ NMR (600 MHz, DMSO-d6) ppm 10.74 (s, 1 H), 8.39 (s, 1 H), 8.05 (dd, J = 7.7, 1.8 Hz, 1 H), 7.57 (ddd, J = 8.3, 7.2, 2.0 Hz, 1 H), 7.29 (d, J = 8.1 Hz, 1 H), 7.23 (s, 1 H), 7.17-7.1 1 (m, 1 H), 4.10 (s, 3H), 3.33 (s, 3H), 3.32 (s, 3H), 3.30 (br s, 1 H), 3.07-3.02 (m, 1 H), 3.02-2.99 (m, 1 H), 2.92-2.87 (m, 1 H), 2.80 (td, J = 1 1.3, 2.7 Hz, 1 H), 2.73 (td, J = 1 1 .0, 2.7 Hz, 1 H), 2.68-2.63 (m, 1 H), 2.55 (dd, J = 12.0, 9.8 Hz, 1 H), 0.71 (d, J = 6.1 Hz, 3H).
δ0 NMR (151 MHz, DMSO-d6) ppm 162.1 , 156.8, 154.1 , 134.4, 133.2, 131.5, 130.1 , 126.6, 125.7, 121.9, 121.0, 1 12.5, 103.0, 99.4, 56.8, 55.4, 55.3, 53.3, 46.3, 26.8, 26.6, 16.7.
[aD]25 °c = -50.1 (c = 0.3, MeOH).
Scheme 1

The genomes of eukaryotic organisms are highly organised within the nucleus of the cell. The long strands of duplex DNA are wrapped around an octomer of histone proteins (most usually comprising two copies of histones H2A, H2B, H3 and H4) to form a
nucleosome. This basic unit is then further compressed by the aggregation and folding of nucleosomes to form a highly condensed chromatin structure. A range of different states of condensation are possible, and the tightness of this structure varies during the cell cycle, being most compact during the process of cell division. Chromatin structure plays a critical role in regulating gene transcription, which cannot occur efficiently from highly condensed chromatin. The chromatin structure is controlled by a series of post-translational
modifications to histone proteins, notably histones H3 and H4, and most commonly within the histone tails which extend beyond the core nucleosome structure. These modifications include acetylation, methylation, phosphorylation, ubiquitinylation, SUMOylation and numerous others. These epigenetic marks are written and erased by specific enzymes, which place the tags on specific residues within the histone tail, thereby forming an epigenetic code, which is then interpreted by the cell to allow gene specific regulation of chromatin structure and thereby transcription.
Histone acetylation is usually associated with the activation of gene transcription, as the modification loosens the interaction of the DNA and the histone octomer by changing the electrostatics. In addition to this physical change, specific proteins bind to acetylated lysine residues within histones to read the epigenetic code. Bromodomains are small (=1 10 amino acid) distinct domains within proteins that bind to acetylated lysine residues commonly but not exclusively in the context of histones. There is a family of around 50 proteins known to contain bromodomains, and they have a range of functions within the cell.
BRPF1 (also known as peregrin or Protein Br140) is a bromodomain-containing protein that has been shown to bind to acetylated lysine residues in histone tails, including H2AK5ac, H4K12ac and H3K14ac (Poplawski et al, J. Mol. Biol., 2014 426: 1661-1676). BRPF1 also contains several other domains typically found in chromatin-associated factors, including a double plant homeodomain (PHD) and zinc finger (ZnF) assembly (PZP), and a chromo/Tudor-related Pro-Trp-Trp-Pro (PWWP) domain. BRPF1 forms a tetrameric complex with monocytic leukemia zinc-finger protein (MOZ, also known as KAT6A or MYST3) inhibitor of growth 5 (ING5) and homolog of Esa1 -associated factor (hEAF6). In humans, the t(8;16)(p1 1 ;p13) translocation of MOZ (monocytic leukemia zinc-finger protein, also known as KAT6A or MYST3) is associated with a subtype of acute myeloid leukemia and
contributes to the progression of this disease (Borrow et al, Nat. Genet., 1996 14: 33-41 ). The BRPF1 bromodomain contributes to recruiting the MOZ complex to distinct sites of active chromatin and hence is considered to play a role in the function of MOZ in regulating transcription, hematopoiesis, leukemogenesis, and other developmental processes (Ullah et al, Mol. Cell. Biol., 2008 28: 6828-6843; Perez-Campo et al, Blood, 2009 1 13: 4866-4874). Demont et al, ACS Med. Chem. Lett., (2014) (dx.doi.org/10.1021/ml5002932), discloses certain 1 ,3-dimethyl benzimidazolones as potent, selective inhibitors of the BRPF1 bromodomain.
BRPF1 bromodomain inhibitors, and thus are believed to have potential utility in the treatment of diseases or conditions for which a bromodomain inhibitor is indicated. Bromodomain inhibitors are believed to be useful in the treatment of a variety of diseases or conditions related to systemic or tissue inflammation, inflammatory responses to infection or hypoxia, cellular activation and proliferation, lipid metabolism, fibrosis and in the prevention and treatment of viral infections. Bromodomain inhibitors may be useful in the treatment of a wide variety of chronic autoimmune and inflammatory conditions such as rheumatoid arthritis, osteoarthritis, psoriasis, systemic lupus erythematosus, multiple sclerosis, inflammatory bowel disease (Crohn's disease and ulcerative colitis), asthma, chronic obstructive airways disease, pneumonitis, myocarditis, pericarditis, myositis, eczema, dermatitis (including atopic dermatitis), alopecia, vitiligo, bullous skin diseases, nephritis, vasculitis, atherosclerosis, Alzheimer's disease, depression, Sjogren's syndrome, sialoadenitis, central retinal vein occlusion, branched retinal vein occlusion, Irvine-Gass syndrome (post-cataract and post-surgical), retinitis pigmentosa, pars planitis, birdshot retinochoroidopathy, epiretinal membrane, cystic macular edema, parafoveal telengiectasis, tractional maculopathies, vitreomacular traction syndromes, retinal detachment,
neuroretinitis, idiopathic macular edema, retinitis, dry eye (kerartoconjunctivitis Sicca), vernal keratoconjunctivitis, atopic keratoconjunctivitis, uveitis (such as anterior uveitis, pan uveitis, posterior uveits, uveitis-associated macula edema), scleritis, diabetic retinopathy, diabetic macula edema, age-related macula dystrophy, hepatitis, pancreatitis, primary biliary cirrhosis, sclerosing cholangitis, Addison's disease, hypophysitis, thyroiditis, type I diabetes, type 2 diabetes and acute rejection of transplanted organs. Bromodomain inhibitors may be useful in the treatment of a wide variety of acute inflammatory conditions such as acute gout, nephritis including lupus nephritis, vasculitis with organ involvement such as
glomerulonephritis, vasculitis including giant cell arteritis, Wegener's granulomatosis, Polyarteritis nodosa, Behcet's disease, Kawasaki disease, Takayasu's Arteritis, pyoderma gangrenosum, vasculitis with organ involvement and acute rejection of transplanted organs. Bromodomain inhibitors may be useful in the treatment of diseases or conditions which involve inflammatory responses to infections with bacteria, viruses, fungi, parasites or their toxins, such as sepsis, sepsis syndrome, septic shock, endotoxaemia, systemic inflammatory response syndrome (SIRS), multi-organ dysfunction syndrome, toxic shock syndrome, acute
lung injury, ARDS (adult respiratory distress syndrome), acute renal failure, fulminant hepatitis, burns, acute pancreatitis, post-surgical syndromes, sarcoidosis, Herxheimer reactions, encephalitis, myelitis, meningitis, malaria and SIRS associated with viral infections such as influenza, herpes zoster, herpes simplex and coronavirus. Bromodomain inhibitors may be useful in the treatment of conditions associated with ischaemia-reperfusion injury such as myocardial infarction, cerebro-vascular ischaemia (stroke), acute coronary syndromes, renal reperfusion injury, organ transplantation, coronary artery bypass grafting, cardio-pulmonary bypass procedures, pulmonary, renal, hepatic, gastro-intestinal or peripheral limb embolism. Bromodomain inhibitors may be useful in the treatment of disorders of lipid metabolism via the regulation of APO-A1 such as hypercholesterolemia, atherosclerosis and Alzheimer's disease. Bromodomain inhibitors may be useful in the treatment of fibrotic conditions such as idiopathic pulmonary fibrosis, renal fibrosis, postoperative stricture, keloid scar formation, scleroderma (including morphea) and cardiac fibrosis. Bromodomain inhibitors may be useful in the treatment of a variety of diseases associated with bone remodelling such as osteoporosis, osteopetrosis, pycnodysostosis, Paget's disease of bone, familial expanile osteolysis, expansile skeletal hyperphosphatasia, hyperososis corticalis deformans Juvenilis, juvenile Paget's disease and Camurati
Engelmann disease. Bromodomain inhibitors may be useful in the treatment of viral infections such as herpes virus, human papilloma virus, adenovirus and poxvirus and other DNA viruses. Bromodomain inhibitors may be useful in the treatment of cancer, including hematological (such as leukaemia, lymphoma and multiple myeloma), epithelial including lung, breast and colon carcinomas, midline carcinomas, mesenchymal, hepatic, renal and neurological tumours. Bromodomain inhibitors may be useful in the treatment of one or more cancers selected from brain cancer (gliomas), glioblastomas, Bannayan-Zonana syndrome, Cowden disease, Lhermitte-Duclos disease, breast cancer, inflammatory breast cancer, colorectal cancer, Wilm's tumor, Ewing's sarcoma, rhabdomyosarcoma, ependymoma, medulloblastoma, colon cancer, head and neck cancer, kidney cancer, lung cancer, liver cancer, melanoma, squamous cell carcinoma, ovarian cancer, pancreatic cancer, prostate cancer, sarcoma cancer, osteosarcoma, giant cell tumor of bone, thyroid cancer,
lymphoblastic T-cell leukemia, chronic myelogenous leukemia, chronic lymphocytic leukemia, hairy-cell leukemia, acute lymphoblastic leukemia, acute myelogenous leukemia, chronic neutrophilic leukemia, acute lymphoblastic T-cell leukemia, acute myeloid leukemia, plasmacytoma, immunoblastic large cell leukemia, mantle cell leukemia, multiple myeloma, megakaryoblastic leukemia, acute megakaryocytic leukemia, promyelocytic leukemia, mixed lineage leukaemia, erythroleukemia, malignant lymphoma, Hodgkins lymphoma, non-Hodgkins lymphoma, lymphoblastic T-cell lymphoma, Burkitt's lymphoma, follicular lymphoma, neuroblastoma, bladder cancer, urothelial cancer, vulval cancer, cervical cancer, endometrial cancer, renal cancer, mesothelioma, esophageal cancer, salivary gland cancer, hepatocellular cancer, gastric cancer, nasopharangeal cancer, buccal cancer, cancer of the mouth, GIST (gastrointestinal stromal tumor) and testicular cancer. In one embodiment the cancer is a leukaemia, for example a leukaemia selected from acute monocytic leukemia, acute myelogenous leukemia, chronic myelogenous leukemia, chronic lymphocytic leukemia,
acute myeloid leukemia and mixed lineage leukaemia (MLL). In another embodiment the cancer is multiple myeloma. In another embodiment the cancer is a lung cancer such as small cell lung cancer (SCLC). In another embodiment the cancer is a neuroblastoma. In another embodiment the cancer is Burkitt's lymphoma. In another embodiment the cancer is cervical cancer. In another embodiment the cancer is esophageal cancer. In another embodiment the cancer is ovarian cancer. In another embodiment the cancer is breast cancer. In another embodiment the cancer is colarectal cancer. In one embodiment the disease or condition for which a bromodomain inhibitor is indicated is selected from diseases associated with systemic inflammatory response syndrome, such as sepsis, burns, pancreatitis, major trauma, haemorrhage and ischaemia. In this embodiment the
bromodomain inhibitor would be administered at the point of diagnosis to reduce the incidence of: SIRS, the onset of shock, multi-organ dysfunction syndrome, which includes the onset of acute lung injury, ARDS, acute renal, hepatic, cardiac or gastro-intestinal injury and mortality. In another embodiment the bromodomain inhibitor would be administered prior to surgical or other procedures associated with a high risk of sepsis, haemorrhage, extensive tissue damage, SIRS or MODS (multiple organ dysfunction syndrome). In a particular embodiment the disease or condition for which a bromodomain inhibitor is indicated is sepsis, sepsis syndrome, septic shock and endotoxaemia. In another embodiment, the bromodomain inhibitor is indicated for the treatment of acute or chronic pancreatitis. In another embodiment the bromodomain is indicated for the treatment of burns. In one embodiment the disease or condition for which a bromodomain inhibitor is indicated is selected from herpes simplex infections and reactivations, cold sores, herpes zoster infections and reactivations, chickenpox, shingles, human papilloma virus, human immunodeficiency virus (HIV), cervical neoplasia, adenovirus infections, including acute respiratory disease, poxvirus infections such as cowpox and smallpox and African swine fever virus. In one particular embodiment a bromodomain inhibitor is indicated for the treatment of Human papilloma virus infections of skin or cervical epithelia. In one embodiment the bromodomain inhibitor is indicated for the treatment of latent HIV infection.
WO 2016062737
Scheme 1
Example 1
Step 1
5-fluoro-1 H-benzordlimidazol-2(3H)-one
A stirred solution of 4-fluorobenzene-1 ,2-diamine (15.1 g, 120 mmol) in THF (120 mL) under nitrogen was cooled using an ice-bath and then was treated with di(1 -/-imidazol-1 -yl)methanone (23.4 g, 144 mmol) portion-wise over 15 min. The resulting mixture was slowly warmed to room temperature then was concentrated in vacuo after 2.5 h. The residue was suspended in a mixture of water and DCM (250 mL each) and filtered off. This residue was then washed with water (50 mL) and DCM (50 mL), before being dried at 40 °C under vacuum for 16 h to give the title compound (16.0 g, 105 mmol, 88%) as a brown solid.
LCMS (high pH): Rt 0.57 min; [M-H+]" = 151.1
δΗ NMR (400 MHz, DMSO-d6) ppm 10.73 (br s, 1 H), 10.61 (br s, 1 H), 6.91-6.84 (m, 1 H), 6.78-6.70 (m, 2H).
Step 2
5-fluoro-1 ,3-dimethyl-1 /-/-benzo[dlimidazol-2(3/-/)-one
A solution of 5-fluoro-1 H-benzo[d]imidazol-2(3H)-one (16.0 g, 105 mmol) in DMF (400 mL) under nitrogen was cooled with an ice-bath, using a mechanical stirrer for agitation. It was then treated over 10 min with sodium hydride (60% w/w in mineral oil, 13.1 g, 327 mmol) and the resulting mixture was stirred at this temperature for 30 min before being treated with iodomethane (26.3 mL, 422 mmol) over 30 min. The resulting mixture was then allowed to warm to room temperature and after 1 h was carefully treated with water (500 mL). The aqueous phase was extracted with EtOAc (3 x 800 mL) and the combined organics were washed with brine (1 L), dried over MgS04 and concentrated in vacuo. Purification of the brown residue by flash chromatography on silica gel (SP4, 1.5 kg column, gradient: 0 to 25% (3: 1 EtOAc/EtOH) in cyclohexane) gave the title compound (15.4 g, 86 mmol, 81 %) as a pink solid.
LCMS (high pH): Rt 0.76 min; [M+H+]+ = 181.1
δΗ NMR (400 MHz, CDCI3) ppm 6.86-6.76 (m, 2H), 6.71 (dd, J = 8.3, 2.3 Hz, 1 H), 3.39 (s, 3H), 3.38 (s, 3H).
Step 3
5-fluoro-1 ,3-dimethyl-6-nitro-1 /-/-benzordlimidazol-2(3/-/)-one
A stirred solution of 5-fluoro-1 ,3-dimethyl-1 H-benzo[d]imidazol-2(3/-/)-one (4.55 g, 25.3 mmol) in acetic anhydride (75 mL) under nitrogen was cooled to -30 °C and then was slowly treated with fuming nitric acid (1 .13 mL, 25.3 mmol) making sure that the temperature was kept below -25°C. The solution turned brown once the first drop of acid was added and a thick brown precipitate formed after the addition was complete. The mixture was allowed to slowly warm up to 0 °C then was carefully treated after 1 h with ice-water (100 mL). EtOAc (15 mL) was then added and the resulting mixture was stirred for 20 min. The precipitate formed was filtered off, washed with water (10 mL) and EtOAc (10 mL), and then was dried under vacuum at 40 °C for 16 h to give the title compound (4.82 g, 21 .4mmol, 85%) as a yellow solid.
LCMS (high pH): Rt 0.76 min; [M+H+]+ not detected
δΗ NMR (600 MHz, DMSO-d6) ppm 7.95 (d, J = 6.4 Hz, 1 H, (H-7)), 7.48 (d, J = 1 1.7 Hz, 1 H, (H-4)), 3.38 (s, 3H, (H-10)), 3.37 (s, 3H, (H-12)).
δ0 NMR (151 MHz, DMSO-d6) ppm 154.3 (s, 1 C, (C-2)), 152.3 (d, J = 254.9 Hz, 1 C, (C-5)), 135.5 (d, J = 13.0 Hz, 1 C, (C-9)), 130.1 (d, J = 8.0 Hz, 1 C, (C-6)), 125.7 (s, 1 C, (C-8)), 104.4 (s, 1 C, (C-7)), 97.5 (d, J = 28.5 Hz, 1 C, (C-4)), 27.7 (s, 1 C, (C-12)), 27.4 (s, 1 C, (C-10)).
Step 4
(R)-tert-but \ 4-( 1 ,3-dimethyl-6-nitro-2-oxo-2,3-dihydro-1 H-benzordlimidazol-5-yl)-3-methylpiperazine-1-carboxylate
A stirred suspension of 5-fluoro-1 ,3-dimethyl-6-nitro-1 H-benzo[d]imidazol-2(3/-/)-one (0.924 g, 4.10 mmol), (R)-ie f-butyl 3-methylpiperazine-1 -carboxylate (1.23 g, 6.16 mmol), and DI PEA (1 .43 mL, 8.21 mmol) in DMSO (4 mL) was heated to 120 °C in a Biotage Initiator microwave reactor for 13 h, then to 130 °C for a further 10 h. The reaction mixture was concentrated in vacuo then partitioned between EtOAc and saturated aqueous sodium bicarbonate solution. The aqueous was extracted with EtOAc and the combined organics were dried (Na2S04), filtered, and concentrated in vacuo to give a residue which was purified by silica chromatography (0-100% ethyl acetate in cyclohexane) to give the title compound as an orange/yellow solid (1.542 g, 3.80 mmol, 93%).
LCMS (formate): Rt 1.17 min, [M+H+]+ 406.5.
δΗ NMR (400 MHz, CDCI3) ppm 7.36 (s, 1 H), 6.83 (s, 1 H), 4.04-3.87 (m,1 H), 3.87-3.80 (m, 1 H), 3.43 (s, 6H), 3.35-3.25 (m, 1 H), 3.23-3.08 (m, 2H), 3.00-2.72 (m, 2H), 1.48 (s, 9H), 0.81 (d, J = 6.1 Hz, 3H)
Step 5
(RHerf-butyl 4-(6-amino-1 ,3-dimethyl-2-oxo-2,3-dihydro-1 /-/-benzordlimidazol-5-yl)-3-methylpiperazine-1-carboxylate
To (R)-iert-butyl 4-(1 ,3-dimethyl-6-nitro-2-oxo-2,3-dihydro-1 H-benzo[d]imidazol-5-yl)-3-methylpiperazine-1-carboxylate (1 .542 g) in /'so-propanol (40 mL) was added 5% palladium on carbon (50% paste) (1.50 g) and the mixture was hydrogenated at room temperature and pressure. After 4 h the mixture was filtered, the residue washed with ethanol and DCM, and the filtrate concentrated in vacuo to give a residue which was purified by silica chromatography (50-100% ethyl acetate in cyclohexane) to afford the title compound (1.220 g, 3.25 mmol, 85%) as a cream solid.
LCMS (high pH): Rt 1 .01 min, [M+H+]+ 376.4.
δΗ NMR (400 MHz, CDCI3) ppm 6.69 (s, 1 H), 6.44 (s, 1 H), 4.33-3.87 (m, 4H), 3.36 (s, 3H), 3.35 (s, 3H), 3.20-2.53 (m, 5H), 1.52 (s, 9H), 0.86 (d, J = 6.1 Hz, 3H).
Step 6
(flVferf-butyl 4-(6-(2-methoxybenzamidoV 1 ,3-dimethyl-2-oxo-2,3-dihvdro-1 H-benzordlimidazol-5-yl)-3-methylpiperazine-1 -carboxylate
A stirred solution of (R)-iert-butyl 4-(6-amino-1 ,3-dimethyl-2-oxo-2,3-dihydro-1 /-/-benzo[d]imidazol-5-yl)-3-methylpiperazine-1 -carboxylate (0.254 g, 0.675 mmol) and pyridine (0.164 ml_, 2.025 mmol) in DCM (2 mL) at room temperature was treated 2-methoxybenzoyl chloride (0.182 mL, 1.35 mmol). After 1 h at room temperature the reaction mixture was concentrated in vacuo to give a residue which was taken up in DMSO:MeOH (1 :1 ) and purified by HPLC (Method C, high pH) to give the title compound (0.302 g, 0.592 mmol, 88%) as a white solid.
LCMS (high pH): Rt 1 .27 min, [M+H+]+ 510.5.
δΗ NMR (400 MHz, CDCI3) ppm 10.67 (s, 1 H), 8.53 (s, 1 H), 8.24 (dd, J = 7.8, 1.7 Hz, 1 H), 7.54-7.48 (m, 1 H), 7.18-7.12 (m, 1 H), 7.07 (d, J = 8.1 Hz, 1 H), 6.82 (s, 1 H), 4.27-3.94 (m, 2H), 4.08 (s, 3H), 3.45 (s, 3H), 3.40 (s, 3H), 3.18-2.99 (m, 2H), 2.92-2.70 (m, 3H), 1.50 (s, 9H), 0.87 (d, J = 6.1 Hz, 3H).
Step 7
(R)-N-( 1 ,3-dimethyl-6-(2-methylpiperazin-1 -yl)-2-oxo-2,3-dihydro-1 H-benzordlimidazol-5-yl)-2-methoxybenzamide
A stirred solution of (R)-ie f-butyl 4-(6-(2-methoxybenzamido)-1 ,3-dimethyl-2-oxo-2,3-dihydro-1 /-/-benzo[d]imidazol-5-yl)-3-methylpiperazine-1-carboxylate (302 mg, 0.592 mmol) in DCM (4 mL) at room temperature was treated with trifluoroacetic acid (3 ml_). After 15 minutes the mixture was concentrated in vacuo to give a residue which was loaded on a solid-phase cation exchange (SCX) cartridge (5 g), washed with MeOH, and then eluted with methanolic ammonia (2 M). The appropriate fractions were combined and concentrated in vacuo to give a white solid (240 mg). Half of this material was taken up in DMSO:MeOH (1 :1 ) and purified by HPLC (Method B, high pH) to give the title compound (101 mg, 0.245 mmol, 41 %) as a white solid.
LCMS (high pH): Rt = 0.90 min, [M+H+]+ 410.5.
δΗ NMR (600 MHz, DMSO-d6) ppm 10.74 (s, 1 H), 8.39 (s, 1 H), 8.05 (dd, J = 7.7, 1.8 Hz, 1 H), 7.57 (ddd, J = 8.3, 7.2, 2.0 Hz, 1 H), 7.29 (d, J = 8.1 Hz, 1 H), 7.23 (s, 1 H), 7.17-7.1 1 (m, 1 H), 4.10 (s, 3H), 3.33 (s, 3H), 3.32 (s, 3H), 3.30 (br s, 1 H), 3.07-3.02 (m, 1 H), 3.02-2.99 (m, 1 H), 2.92-2.87 (m, 1 H), 2.80 (td, J = 1 1.3, 2.7 Hz, 1 H), 2.73 (td, J = 1 1 .0, 2.7 Hz, 1 H), 2.68-2.63 (m, 1 H), 2.55 (dd, J = 12.0, 9.8 Hz, 1 H), 0.71 (d, J = 6.1 Hz, 3H).
δ0 NMR (151 MHz, DMSO-d6) ppm 162.1 , 156.8, 154.1 , 134.4, 133.2, 131.5, 130.1 , 126.6, 125.7, 121.9, 121.0, 1 12.5, 103.0, 99.4, 56.8, 55.4, 55.3, 53.3, 46.3, 26.8, 26.6, 16.7.
[aD]25 °c = -50.1 (c = 0.3, MeOH).






Abstract Image
The BRPF (Bromodomain and PHD Finger-containing) protein family are important scaffolding proteins for assembly of MYST histone acetyltransferase complexes. A selective benzimidazolone BRPF1 inhibitor showing micromolar activity in a cellular target engagement assay was recently described. Herein, we report the optimization of this series leading to the identification of a superior BRPF1 inhibitor suitable for in vivo studies.

GSK6853, a Chemical Probe for Inhibition of the BRPF1 Bromodomain

Epinova Discovery Performance Unit, Quantitative Pharmacology, Experimental Medicine Unit, §Flexible Discovery Unit, and Platform Technology and Science, GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K.
 Cellzome GmbH, GlaxoSmithKline, Meyerhofstrasse 1, 69117 Heidelberg, Germany
# WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Thomas Graham Building, 295 Cathedral Street, Glasgow G1 1XL, U.K.
ACS Med. Chem. Lett., Article ASAP
DOI: 10.1021/acsmedchemlett.6b00092

//////////////BRPF1,  BRPF2,   bromodomain, chemical probe,  inhibitor, GSK 6853, PRECLINICAL

  • Supporting Info  SEE NMR COMPD 34,  SMILES       COc1ccccc1C(=O)Nc2cc4c(cc2N3CCNC[C@H]3C)N(C)C(=O)N4C

[18F]AMG 580


[18F]AMG 580

CAS 1879904-74-1
MF C26 H24 F N5 O3
NOTE.........CAS OF AMG 580 IS 1227067-71-1, WITHOUT 18F
AMG 580 [1-(4-(3-(4-(1H-benzo[d]imidazole-2-carbonyl)phenoxy)pyrazin-2-yl)piperidin-1-yl)-2-fluoropropan-1-one],
Phosphodiesterase 10A (PDE10A) inhibitors have therapeutic potential for the treatment of psychiatric and neurologic disorders, such as schizophrenia and Huntington’s disease. One of the key requirements for successful central nervous system drug development is to demonstrate target coverage of therapeutic candidates in brain for lead optimization in the drug discovery phase and for assisting dose selection in clinical development. Therefore, we identified AMG 580 [1-(4-(3-(4-(1H-benzo[d]imidazole-2-carbonyl)phenoxy)pyrazin-2-yl)piperidin-1-yl)-2-fluoropropan-1-one], a novel, selective small-molecule antagonist with subnanomolar affinity for rat, primate, and human PDE10A. We showed that AMG 580 is suitable as a tracer for lead optimization to determine target coverage by novel PDE10A inhibitors using triple-stage quadrupole liquid chromatography–tandem mass spectrometry technology. [3H]AMG 580 bound with high affinity in a specific and saturable manner to both striatal homogenates and brain slices from rats, baboons, and human in vitro. Moreover, [18F]AMG 580 demonstrated prominent uptake by positron emission tomography in rats, suggesting that radiolabeled AMG 580 may be suitable for further development as a noninvasive radiotracer for target coverage measurements in clinical studies. These results indicate that AMG 580 is a potential imaging biomarker for mapping PDE10A distribution and ensuring target coverage by therapeutic PDE10A inhibitors in clinical studies.



Abstract Image
We report the discovery of PDE10A PET tracer AMG 580 developed to support proof of concept studies with PDE10A inhibitors in the clinic. To find a tracer with higher binding potential (BPND) in NHP than our previously reported tracer 1, we implemented a surface plasmon resonance assay to measure the binding off-rate to identify candidates with slower washout rate in vivo. Five candidates (26) from two structurally distinct scaffolds were identified that possessed both the in vitro characteristics that would favor central penetration and the structural features necessary for PET isotope radiolabeling. Two cinnolines (23) and one keto-benzimidazole (5) exhibited PDE10A target specificity and brain uptake comparable to or better than 1 in the in vivo LC–MS/MS kinetics distribution study in SD rats. In NHP PET imaging study, [18F]-5 produced a significantly improved BPND of 3.1 and was nominated as PDE10A PET tracer clinical candidate for further studies.

Discovery of Phosphodiesterase 10A (PDE10A) PET Tracer AMG 580 to Support Clinical Studies

Department of Medicinal Chemistry, Department of Pharmacokinetics and Drug Metabolism, §Department of Neuroscience, and ΔDepartment of Early Development, Amgen Inc., One Amgen Center Drive, Thousand Oaks, California 93012-1799, United States
Department of Neuroscience and ±Department of Pharmacokinetics and Drug Metabolism, Amgen Inc., 1120 Veterans Boulevard, South San Francisco, California 94080, United States
 Department of Molecular Structure and Characterization, Amgen Inc., 360 Binney Street, Cambridge, Massachusetts 02142, United States
ACS Med. Chem. Lett., Article ASAP
DOI: 10.1021/acsmedchemlett.6b00185
*Phone: 805-313-5300. E-mail: ehu@amgen.com.

WO 2010057121

Nuclear Medicine and Biology (2015), 42(8), 654-663.
Phosphodiesterase 10A (PDE10A) is an intracellular enzyme responsible for the breakdown of cyclic nucleotides which are important second messengers for neurotransmission. Inhibition of PDE10A has been identified as a potential target for treatment of various neuropsychiatric disorders. To assist drug development, we have identified a selective PDE10A positron emission tomography (PET) tracer, AMG 580. We describe here the radiosynthesis of [18 F]AMG 580 and in vitro and in vivo characterization results.
AMG 580 has an in vitro KD of 71.9 pM. Autoradiography showed specific uptake in striatum. Mean activity of 121 ± 18 MBq was used in PET studies. In Rhesus, the baseline BPND for putamen and caudate was 3.38 and 2.34, respectively, via 2TC, and 3.16, 2.34 via Logan, and 2.92, and 2.01 via SRTM. A dose dependent decrease of BPNDwas observed by the pre-treatment with a PDE10A inhibitor. In baboons, 0.24 mg/kg dose of AMG 580 resulted in about 70% decrease of BPND. The in vivo KD of [18 F]AMG 580 was estimated to be around 0.44 nM in baboons.


[18 F]AMG 580 is a selective and potent PDE10A PET tracer with excellent specific striatal binding in non-human primates. It warrants further evaluation in humans.

///Phosphodiesterasetracer,  receptor occupancy,  positron emission tomographyradiotracer,  brain penetrationAMG 580, Phosphodiesterase 10A, PDE10A, PET Tracer, [18F]AMG 580