Publications by authors named "Kotaro Ochiai"

We previously revealed that phosphine-boranes can function as molecular frameworks for biofunctional molecules. In the present study, we exploited the diversity of available phosphines to design and synthesize a series of -(trifluoromethyl)phenyl phosphine-borane derivatives as novel progesterone receptor (PR) antagonists. We revealed that the synthesized phosphine-borane derivatives exhibited Log values in a predictable manner and that the P-H group in the phosphine-borane was almost nonpolar.

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We previously identified nitrophenylferrocenes and cyanophenylferrocenes as promising lead structures of novel androgen receptor (AR) antagonists, based on the structural similarity between ferrocene and the steroidal skeleton. In the present research, we explored the structure-activity relationship (SAR) of phenylferrocene derivatives. Introduction of a hydrophobic substituent such as a chlorine atom at the 2-position or 3-position of phenylferrocene derivatives significantly increased the antagonistic activity toward wild-type AR, and among the synthesized compounds, 3-chloro-4-cyanophenylferrocene (29) exhibited the most potent anti-proliferative activity toward the androgen-dependent growth of SC-3 cells expressing wild-type AR (IC 14 nM).

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Article Synopsis
  • The research focuses on developing new drug candidates by increasing structural diversity in medicinal chemistry, specifically through the design of -hydroxyphenyl phosphine borane derivatives.
  • The synthesized derivatives showed good stability in water, less hydrophobicity compared to alkanes and silanes, and adequate affinity for lipid membranes, which is important for drug permeability.
  • Some of the -hydroxyphenyl phosphine borane derivatives demonstrated significant activity as estrogen receptor agonists, highlighting the potential of this framework in drug discovery.
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Cycloheptatrienyl (tropyl) molecules are representative non-alternant hydrocarbons that offer interesting chemistry because of their unique structures and properties. However, there have been a limited number of polycyclic aromatic tropyl cations and radicals reported in the literature. Herein, we report the synthesis of a series of azahomocorannulene derivatives, where the key reactions are a 1,3-dipolar cycloaddition of polycyclic aromatic azomethine ylides with dibenzotropone and a subsequent palladium-catalyzed cyclization.

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Article Synopsis
  • * The research focuses on synthesizing and analyzing new π-extended pyrrole-fused heteropine compounds, specifically thiepine and oxepine.
  • * A notable finding is that a π-extended pyrrole-fused thiepine demonstrated a unique "pitched π-stacking" structure, resulting in a high charge carrier mobility of 1.0 cm V s in single-crystal field-effect transistors.
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Ferrocene is a representative organometallic compound having a sandwich structure with high stability and hydrophobicity. In this study, we determined the physicochemical properties of a series of nitro- and cyanophenylferrocenes, and evaluated their biological activity as androgen receptor (AR) antagonists. Ferrocene derivatives exhibited hydrophobicity parameter π values in the range between 2.

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Here we report the 1,3-dipolar cycloaddition of polycyclic aromatic azomethine ylides with nitriles to produce highly fused imidazole derivatives, that is, tribenzo[,,]imidazo[2,1,5-]quinolizine. The advantages of this transformation are the broad substrate scope and the good functional group compatibility. The subsequent palladium-catalyzed intramolecular cyclization provides an efficient approach to further π-extended imidazoles, that is, 14b,15-diazadibenzo[,]cyclopenta[]pentaphene.

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