Publications by authors named "Kazuki Otake"

A variety of RORγ inhibitors have been identified, including clinical compounds such as VTP-43742 and JTE-151. In contrast, RORγ agonists have been less explored and LYC-55716 is, to the best of our knowledge, the sole example reached a human clinical investigation. To generate a novel RORγ agonist, functionality switching from preceding RORγ inhibitors has been considered as a rational strategy.

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Voltage-gated potassium (Kv) channels contribute to repolarization in excitable tissues such as nerves and cardiac muscle; consequently, they control the firing frequency and duration of action potential. Their dysfunction can thus cause neurological disorders and cardiac disorders with arrhythmias. The dysfunction of Kv11.

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Phosphodiesterases (PDEs) have drawn attention due to their critical roles in physiological and pathological conditions. Many research groups have studied these hydrolytic enzymes to develop new drugs, including apremilast as a PDE4 inhibitor and sildenafil as a PDE5 inhibitor. Targeting PDE7 has also been deemed a rational strategy to ameliorate autoimmune conditions.

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In research focused on protein-protein interaction (PPI) inhibitors, the optimization process to achieve both high inhibitory activity and favorable physicochemical properties remains challenging. Our previous study reported the discovery of novel and bioavailable Keap1-Nrf2 PPI inhibitor which exhibited moderate in vivo activity in rats. In this work, we present our subsequent efforts to optimize this compound.

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Protein-protein interactions (PPIs) play a crucial role in most biological processes and are important targets in the development of therapeutic agents. However, small molecule drug discovery that targets PPIs remains very challenging. Targeting hot spot residues is considered the best option for inhibiting such interactions, but there are few examples of how knowledge of hot spots can be used in high throughput screening to find hit compounds.

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Oxidative stress is one of the causes of progression of chronic kidney disease (CKD). Activation of the antioxidant protein regulator Nrf2 by inhibition of the Keap1-Nrf2 protein-protein interaction (PPI) is of interest as a potential treatment for CKD. We report the identification of the novel and weak PPI inhibitor with good physical properties by a high throughput screening (HTS) campaign, followed by structural and computational analysis.

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A mild and efficient method for formation of methylene acetals from 1,2- and 1,3-diols using methoxymethylphenylsulfide, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), and dibutylhydroxytoluene (BHT) is described. The use of BHT in this process suppresses side reactions and enables high-yielding formation of methylene acetals of various diols, including carbohydrate-type substrates.

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Highly substituted four- and five-membered heterocycles were prepared starting with O,P- and N,P-acetals by using a one-pot method involving base induced cyclization and a Horner-Wadsworth-Emmons (HWE) olefination reaction. Divergent synthesis of various heterocycles was achieved by using this method and transformations of the alkenyl group in the products of these processes were exemplified. Finally, a short and efficient synthesis of (±)-pseudodeflectusin based on the new methodology was achieved.

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The effects of phosphorus substituents on the reactivity of α-alkoxyphosphonium salts with nucleophiles has been explored. Reactions of α-alkoxyphosphonium salts, prepared from various acetals and tris(o-tolyl)phosphine, with a variety of nucleophiles proceeded efficiently. These processes represent the first examples of high-yielding nucleophilic substitution reactions of α-alkoxyphosphonium salts.

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An unusual and novel reaction of α-alkoxyphosphonium salts, generated from O,O-acetals and Ph(3)P, with Grignard reagents under an O(2) atmosphere afforded alcohols in moderate to high yields. It was clarified by isotopic labelling experiments that the reaction proceeded via a novel radical pathway.

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A new direct conversion of O,O-acetals to esters via O,P-acetal intermediates was developed. The regioselective cleavage of unsymmetrical cyclic acetals occurred to give the more crowded esters as single isomers.

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The structure and electronic nature of the phosphine have a significant influence on not only the formation, but also the subsequent transformation of O,P-acetals. The O,P-acetals generated from tris(o-tolyl)phosphine [(o-tol)(3)P] underwent efficient substitution reactions with various nucleophiles.

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