Publications by authors named "Hirotada Takahashi"

Article Synopsis
  • The research focused on optimizing a lead compound to enhance its mPGES-1 inhibitory activity and improve its ADME profile by making substitutions at specific positions.
  • By replacing bromine in the lead compound with different groups, the phenyl group was found to be the most effective for strong inhibitory activity and favorable ADME characteristics.
  • Ultimately, compound 39 emerged as the top candidate, demonstrating impressive mPGES-1 inhibition, potent cell activity, and excellent oral absorption in tests.
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We have previously reported 7-bromo-2-(2-chrolophenyl)-imidazoquinolin-4(5H)-one (1) as a novel potent mPGES-1 inhibitor. To clarify the essential functional groups of 1 for inhibition of mPGES-1, we investigated this compound structure-activity relationship following substitution at the C(4)-position and N-alkylation at the N(1)-, the N(3)-, and the N(5)-positions of 1. To prepare the target compounds, we established a good methodology for selective N-alkylation of the imidazoquinolin-4-one, that is, selective alkylation of 1 at the N(3)- and N(5)-positions was achieved by use of an appropriate base and introduction of a protecting group at the nitrogen atom in the imidazole part, respectively.

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The imidazoquinoline derivative 1 was found as a novel mPGES-1 inhibitor. Optimization of 1 led to the identification of the 2-chlorophenyl group at the C(2)-position and the quinolone structure at the C(4)-position. Compound 33, the most potent synthesized compound, showed excellent mPGES-1 inhibition (IC(50)=9.

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In this study, we have investigated the roles of substituents on the terminal phenyl ring at the C(4)-position of the quinazoline core to complete the structure-activity relationships (SARs) of our NF-kappa B activation inhibitors. Among them, compound 12j afforded highly potent inhibitory activity toward NF-kappa B transcriptional activation with IC(50) value of 2 nM, along with an excellent in vivo efficacy by reducing the edema formation seen in carrageenin-induced inflammation of the rat hind paw.

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We disclose here a new structural class of low-molecular-weight inhibitors of NF-kappa B activation that were designed and synthesized by starting from quinazoline derivative 6a. Structure-activity relationship (SAR) studies based on 6a elucidated the structural requirements essential for the inhibitory activity toward NF-kappa B transcriptional activation, and led to the identification of the 6-amino-4-phenethylaminoquinazoline skeleton as the basic framework. In this series of compounds, 11q, containing the 4-phenoxyphenethyl moiety at the C(4)-position, showed strong inhibitory effects on both NF-kappa B transcriptional activation and TNF-alpha production.

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In the present study, we have found that mono-unsaturated linear-chain fatty acids in the cis configuration with C(18) hydrocarbon chains (i.e. oleic acid) strongly inhibited the activity of human telomerase in a cell-free enzymic assay, with an IC(50) value of 8.

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