Publications by authors named "Hiroyuki Koshio"

Diffuse large B-cell lymphoma (DLBCL), the most common type of B-cell non-Hodgkin lymphoma (NHL), is categorized into two major subtypes, activated B-cell-like (ABC) and germinal center B-cell-like (GCB). The ABC subtype is associated with worse prognosis than the GCB subtype using currently available therapies such as combination treatment with rituximab plus standard cytotoxic chemotherapy. The B-cell receptor (BCR) pathway is activated in ABC DLBCL, suggesting that inhibition of this pathway could provide an alternative strategy for treatment.

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First- and second-generation EGFR tyrosine kinase inhibitors (TKI) are effective clinical therapies for patients with non-small cell lung cancer (NSCLC) harboring EGFR-activating mutations. However, almost all patients develop resistance to these drugs. The EGFR T790M mutation of EGFR is the most predominant mechanism for resistance.

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Inhibitors of factor Xa (FXa), a crucial serine protease in the coagulation cascade, have attracted a great deal of attention as a target for developing antithrombotic agents. We previously reported findings from our optimization study of a high-throughput screening (HTS) derived lead compound 1a that resulted in the discovery of potent amidine-containing FXa inhibitors represented by compound 2. We also conducted an alternative optimization study of 1a without incorporating a strong basic amidine group, which generally has an adverse effect on the pharmacokinetic profile after oral administration.

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A series of (4,4-difluoro-1,2,3,4-tetrahydro-5H-1-benzazepine-5-ylidene)acetamide derivatives were optimized to achieve potent agonistic activity, both in vitro and in vivo, for the arginine vasopressin V(2) receptor, resulting in the eventual discovery of compound 1g. Molecular modeling of compound 1g with V(2) receptor was also examined to evaluate the binding mode of this series of compounds.

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A series of (4,4-difluoro-1,2,3,4-tetrahydro-5H-1-benzazepin-5-ylidene)acetamide derivatives was synthesized, and their structure-activity relationships were examined in order to identify potent and selective arginine vasopressin V(2) receptor agonists. Attempts to substitute other chemical groups in place of the 2-pyridilmethyl moiety of 1a led to the discovery that potent V(2) binding affinity could be obtained with a wide range of functional groups. This structural tolerance allowed for the manipulation of other attributes, such as selectivity against V(1a) receptor affinity or avoidance of the undesirable inhibition of cytochrome P450 (CYP), without losing potent affinity for the V(2) receptor.

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The present work describes the discovery of novel series of (4,4-difluoro-1,2,3,4-tetrahydro-5H-1-benzazepine-5-ylidene)acetamide derivatives as arginine vasopressin (AVP) V(2) receptor agonists. By replacing the amide juncture in YM-35278 with a direct ring connection gave compound 10a, which acts as a V(2) receptor agonist. These studies provided the potent, orally active non-peptidic V(2) receptor agonists 10a and 10j.

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We describe here our investigation of a new series of orally active fXa inhibitors based on a prodrug strategy. Solid-phase parallel synthesis identified a unique series of fXa inhibitors with a substituted benzenesulfonyl group as a novel S4 binding element. This series resulted in compound 39, which exhibited potent inhibitory activity against fXa (IC50 = 13 nM) and excellent selectivity over thrombin (>7000-fold).

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A practical and cost-effective procedure has been developed for the synthesis of 7-methyl-2-naphthalenecarbonitrile, the precursor of the anticoagulant agents YM-60828 or YM-96765. This new route generates the key intermediate in only two steps from readily available 3-cyanopropionaldehyde dimethyl acetal and m-tolualdehyde, without requiring chromatographic purification. The synthesis involves condensation of the cyano derivative with the aldehyde and subsequent cyclodehydration.

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Factor Xa (fXa) is a serine protease that plays a pivotal role in the coagulation cascade. High-throughput screening of the Yamanouchi compound library yielded lead compound 1 with the ability to inhibit fXa at micromolar concentrations. To improve its fXa inhibitory activity and its oral anticoagulant activity, the linker between benzamidine and the central benzene ring was modified and a carboxyl group was introduced at the central benzene ring.

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Factor Xa (fXa) is a serine protease, which plays a pivotal role in the coagulation cascade. To improve the oral anticoagulant activity of fXa inhibitors containing a 1,4-diazepane moiety as the P4 part, a prodrug strategy was examined. Among the compounds evaluated in this study, amidoxime prodrugs bearing an ester moiety, such as compounds 21 and 30, showed effective oral anticoagulant activity in mice.

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Factor Xa (fXa) is a serine protease involved in the coagulation cascade, which has received great interest as a potential target for the development of new antithrombotic drugs. Herein we report a novel series of fXa inhibitors in which the 1,4-diazepane moiety was designed to interact with the S4 aryl-binding domain of the fXa active site. Compound 13 (YM-96765) showed potent fXa inhibitory activity (IC(50) = 6.

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The syntheses and biological evaluation of a series of novel indeno[1,2-d]thiazole derivatives are described. Several groups reported 5-HT(3) receptor agonists which were mainly evaluated for their activities on the von Bezold-Jarisch reflex (B-J reflex). We discovered that tetrahydrothiazolopyridine derivative 1b had a contractile effect on the isolated guinea pig colon with weak B-J reflex.

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Compound YM-60828 was previously characterized in our laboratory as a potent, selective and orally-bioavailable Factor Xa (FXa) inhibitor. The L-shape conformation of this compound in the active site of FXa was recognized as an important factor in displaying its FXa inhibitory activity. This led to the exploration of conformationally restricted cyclic scaffolds bearing a similar active conformation.

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Factor Xa (FXa) is a serine protease which plays a pivotal role in the coagulation cascade. The inhibition of FXa has received great interest as a potential target for the development of new antithrombotic drug. Herein we describe a series of novel 7-amidino-2-naphthoanilide and 7-amidino-2-naphthalensulfonanilide derivatives which are potent FXa inhibitors.

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Since Factor Xa (FXa) is well known to play a central role in thrombosis and hemostasis, inhibition of FXa is an attractive target for antithrombotic strategies. As a part of our investigation of a non-peptide, orally available FXa inhibitor, we found that a series of N-[(7-amidino-2-naphthyl)methyl]aniline derivatives possessed potent and selective inhibitory activities. Structure--activity relationship (SAR) of the substituent (R(1)) on the central aniline moiety suggested that increasing lipophilicity caused a detrimental effect on anticoagulant activity (prothrombin time assay) in plasma.

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