Masakuni Kori

2-{3-[4-(Alkylsulfinyl)phenyl]-1-benzofuran-5-yl}-5-methyl-1,3,4-oxadiazole derivatives as novel inhibitors of glycogen synthase kinase-3beta with good brain permeability.

Glycogen synthase kinase 3beta (GSK-3beta) inhibition is expected to be a promising therapeutic approach for treating Alzheimers disease. Previously we reported a series of 1,3,4-oxadiazole derivatives as potent and highly selective GSK-3beta inhibitors, however, the representative compounds 1a,b showed poor pharmacokinetic profiles. Efforts were made to address this issue by reducing molecular weight and lipophilicity, leading to the identification of oxadiazole derivatives containing a sulfinyl group, (S)-9b and (S)-9c. These compounds exhibited not only highly selective and potent inhibitory activity against GSK-3beta but also showed good pharmacokinetic profiles including favorable BBB penetration. In addition, (S)-9b and (S)-9c given orally to mice significantly inhibited cold water stress-induced tau hyperphosphorylation in mouse brain.

A novel glycogen synthase kinase-3 inhibitor 2-methyl-5-(3-{4-[(S )-methylsulfinyl]phenyl}-1-benzofuran-5-yl)-1,3,4-oxadiazole decreases tau phosphorylation and ameliorates cognitive deficits in a transgenic model of Alzheimer’s disease

J. Neurochem. (2011) 10.1111/j.1471‐4159.2011.07532.x

Efficacy of a novel, orally active GSK-3 inhibitor 6-Methyl-N-[3-[[3-(1-methylethoxy)propyl]carbamoyl]-1H-pyrazol-4-yl]pyridine-3-carboxamide in tau transgenic mice

Neurofibrillary tangles (NFTs) composed of hyperphosphorylated and aggregated tau are common pathological characteristics in Alzheimers disease (AD) and other tauopathies. Aberrant tau phosphorylation is an early and pivotal event in the pathogenesis of tauopathies, and since GSK-3 is a key factor implicated in aberrant tau phosphorylation, GSK-3 inhibition is expected to suppress tauopathy disease progression. In the present study, we report the efficacy of a newly discovered small molecule GSK-3 inhibitor, 6-methyl-N-[3-[[3-(1-methylethoxy)propyl]carbamoyl]-1H-pyrazol-4-yl]pyridine-3-carboxamide (compound A), to inhibit tau phosphorylation and to reduce the amount of pathological aggregated tau in JNPL3 mice that overexpress a mutant form of human tau. Compound A is a highly potent and selective inhibitor of GSK-3 with an IC(50) of 2 nM, with at least 230-fold lower potency against 27 other kinases. Oral administration of compound A resulted in a significant reduction of tau phosphorylation at several GSK-3 directed sites. Furthermore, chronic oral administration of compound A markedly reduced aggregated tau in old JNPL3 mice. These results suggest that a novel, orally active GSK-3 inhibitor, compound A, has potency in the prevention of tau pathology.

Syntheses of fused heterocyclic compounds and their inhibitory activities for squalene synthase.

A variety of fused heterocyclic compounds (2-11) were synthesized as a modification of the lead compound 1a and evaluated for their inhibition of squalene synthase. 4,1-Benzothiazepine derivative 2, 1,4-benzodiazepine derivative 6, 1,3-benzodiazepine derivative 7, 1-benzazepine derivative 9, and 4,1-benzoxazocine derivative 10 potently inhibited squalene synthase activity, whereas the 4,1-benzoxazepine derivatives 1 was the most potent inhibitor. 4,1-Benzothiazepine S-oxide derivative 4, 1,4-benzodiazepine derivative 5, 1,3,4-benzotriazepine derivative 8, and 1,2,3,4-tetrahydroquinoline derivative 11 were found to be weakly active. Comparison of the X-ray structures of these compounds (1a, 2, 4, 5, 7 and 10) suggests that orientation of the 5- (or 6)-phenyl group is important for activity.

Synthesis, SAR study, and biological evaluation of a series of piperazine ureas as fatty acid amide hydrolase (FAAH) inhibitors

A series of piperazine ureas was designed, synthesized, and evaluated for their potential as novel orally available fatty acid amide hydrolase (FAAH) inhibitors that are therapeutically effective against pain. We carried out an optimization study of the lead compound 3 to improve its DMPK profile as well as in vitro potency. We identified the thiazole compound 60j with potent inhibitory activity, high brain permeability, and good bioavailability. Compound 60j showed a potent and dose-dependent anti-nociceptive effect in the acetic acid-induced writhing test in mice.

Thieno[2,3-d]pyrimidine-2-carboxamides bearing a carboxybenzene group at 5-position: Highly potent, selective, and orally available MMP-13 inhibitors interacting with the S1 binding site

On the basis of X-ray co-crystal structures of matrix metalloproteinase-13 (MMP-13) in complex with its inhibitors, our structure-based drug design (SBDD) strategy was directed to achieving high affinity through optimal protein-ligand interaction with the unique S1″ hydrophobic specificity pocket. This report details the optimization of lead compound 44 to highly potent and selective MMP-13 inhibitors based on fused pyrimidine scaffolds represented by the thienopyrimidin-4-one 26c. Furthermore, we have examined the release of collagen fragments from bovine nasal cartilage in response to a combination of IL-1 and oncostatin M.

Discovery of the First Potent and Orally Available Agonist of the Orphan G-Protein-Coupled Receptor 52

G-protein-coupled receptor 52 (GPR52) is an orphan Gs-coupled G-protein-coupled receptor. GPR52 inhibits dopamine D2 receptor signaling and activates dopamine D1/N-methyl-d-aspartate receptors via intracellular cAMP accumulation, and therefore, GPR52 agonists may have potential as a novel class of antipsychotics. A series of GPR52 agonists with a bicyclic core was designed to fix the conformation of the phenethyl ether moiety of compounds 2a and 2b. 3-[2-(3-Chloro-5-fluorobenzyl)-1-benzothiophen-7-yl]-N-(2-methoxyethyl)benzamide 7m showed potent activity (pEC50 = 7.53 ± 0.08) and good pharmacokinetic properties. Compound 7m significantly suppressed methamphetamine-induced hyperactivity in mice after oral administration of 3 mg/kg without disturbance of motor function.

Design, Synthesis, and Biological Evaluation of a Series of Piperazine Ureas as Fatty Acid Amide Hydrolase Inhibitors

A series of piperazine ureas were designed, synthesized, and evaluated for their potential as novel orally efficacious fatty acid amide hydrolase (FAAH) inhibitors for the treatment of neuropathic and inflammatory pain. We carried out an optimization study of compound 5 to improve its in vitro FAAH inhibitory activity, and identified the 2-pyrimidinylpiperazine derivative 21d with potent inhibitory activity, favorable DMPK profile and brain permeability. Compound 21d showed robust and dose-dependent analgesic efficacy in animal models of both neuropathic and inflammatory pain.

Design and Synthesis of Benzimidazoles As Novel Corticotropin-Releasing Factor 1 Receptor Antagonists

Benzazole derivatives with a flexible aryl group bonded through a one-atom linker as a new scaffold for a corticotropin-releasing factor 1 (CRF1) receptor antagonist were designed, synthesized, and evaluated. We expected that structural diversity could be expanded beyond that of reported CRF1 receptor antagonists. In a structure-activity relationship study, 4-chloro-N(2)-(4-chloro-2-methoxy-6-methylphenyl)-1-methyl-N(7),N(7)-dipropyl-1H-benzimidazole-2,7-diamine 29g had the most potent binding activity against a human CRF1 receptor and the antagonistic activity (IC50 = 9.5 and 88 nM, respectively) without concerns regarding cytotoxicity at 30 μM. Potent CRF1 receptor-binding activity in brain in an ex vivo test and suppression of stress-induced activation of the hypothalamus-pituitary-adrenocortical (HPA) axis were also observed at 138 μmol/kg of compound 29g after oral administration in mice. Thus, the newly designed benzimidazole 29g showed in vivo CRF1 receptor antagonistic activity and good brain penetration, indicating that it is a promising lead for CRF1 receptor antagonist drug discovery research.

Discovery of Novel, Highly Potent, and Selective Matrix Metalloproteinase (MMP)-13 Inhibitors with a 1,2,4-Triazol-3-yl Moiety as a Zinc Binding Group Using a Structure-Based Design Approach

On the basis of a superposition study of X-ray crystal structures of complexes of quinazoline derivative 1 and triazole derivative 2 with matrix metalloproteinase (MMP)-13 catalytic domain, a novel series of fused pyrimidine compounds which possess a 1,2,4-triazol-3-yl group as a zinc binding group (ZBG) was designed. Among the herein described and evaluated compounds, 31f exhibited excellent potency for MMP-13 (IC50 = 0.036 nM) and selectivities (greater than 1,500-fold) over other MMPs (MMP-1, -2, -3, -7, -8, -9, -10, and -14) and tumor necrosis factor-α converting enzyme (TACE). Furthermore, the inhibitor was shown to protect bovine nasal cartilage explants against degradation induced by interleukin-1 and oncostatin M. In this article, we report the discovery of extremely potent, highly selective, and orally bioavailable fused pyrimidine derivatives that possess a 1,2,4-triazol-3-yl group as a novel ZBG for selective MMP-13 inhibition.