Publications by authors named "Akito Yasuhara"

We previously identified 3-chloro-N-{(S)-[3-(1-ethyl-1H-pyrazol-4-yl)phenyl][(2S)-piperidine-2-yl]methyl}-4-(trifluoromethyl)pyridine-2-carboxamide (5, TP0439150) as a potent and orally available glycine transporter 1 (GlyT1) inhibitor. In this article, we describe our identification of 1-methyl-N-(propan-2-yl)-N-({2-[4-(trifluoromethoxy)phenyl]pyridin-4-yl}methyl)-1H-imidazole-4-carboxamide (7n) as a structurally diverse back-up compound of 5, using central nervous system multiparameter optimization (CNS MPO) as a drug-likeness guideline. Compound 7n showed a higher CNS MPO score and different physicochemical properties as compared to 5.

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Glutamatergic dysfunction has been implicated in psychiatric disorders such as schizophrenia. The stimulation of metabotropic glutamate (mGlu) 2 receptor has been shown to be effective in a number of animal models of schizophrenia. In this study, we investigated the antipsychotic profiles of (2S)-5-methyl-2-{[4-(1,1,1-trifluoro-2-methylpropan-2-yl)phenoxy]methyl}-2,3-dihydroimidazo[2,1-b][1,3]oxazole-6-carboxamide (TASP0443294), a newly synthesized positive allosteric modulator of the mGlu2 receptor.

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Excess glutamatergic neurotransmission has been implicated in the pathophysiology of schizophrenia, and the activation of metabotropic glutamate 2 (mGlu2) receptor may exert antipsychotic effects by normalizing glutamate transmission. In the present study, we investigated the neurophysiologic and antipsychotic profiles of TASP0433864 [(2S)-2-[(4-tert-butylphenoxy)methyl]-5-methyl-2,3-dihydroimidazo[2,1-b][1,3]oxazole-6-carboxamide], a newly synthesized positive allosteric modulator (PAM) of mGlu2 receptor. TASP0433864 exhibited PAM activity at human and rat mGlu2 receptors with EC50 values of 199 and 206 nM, respectively, without exerting agonist activity at rat mGlu2 receptor.

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Metabotropic glutamate receptors (mGlu receptors) have emerged as new therapeutic targets for psychiatric disorders, such as schizophrenia, depression and anxiety with their regulatory roles in glutamatergic transmissions. To date, several ligands selective for each mGlu receptor have been synthesized, and pharmacological significances of these ligands have been demonstrated in animal models. Among them, mGlu2/3 receptor agonists have been proven to be effective for treating schizophrenia and anxiety disorders in clinical studies, which may prove utilities of mGlu receptor ligands for the treatment of psychiatric disorders.

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In this paper, we describe the synthesis of (+)-(1R( *),2R( *))-2-[(1S( *))-1-amino-1-carboxy-2-(9H-xanthen-9-yl)-ethyl]-1-fluorocyclopropanecarboxylic acid (+)-16a, a compound, that is, fluorinated at the alpha position of the carboxylic acid in the cyclopropane ring of a group II mGluRs antagonist, 1 (LY341495), using a previously reported stereoselective cyclopropanation reaction. The fluorinated compound (+)-16a exhibited almost the same affinity (IC(50)=3.49 nM) for mGluR2 as 1 but had a superior pharmacokinetic profile.

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3-(3,4-Dichlorobenzyloxy)-2-amino-6-fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid 5 (MGS0039) is a highly selective and potent group II metabotropic glutamate receptor (mGluR) antagonist (antagonist activities for mGluR2; IC50=20.

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Glutamatergic abnormalities play roles in several psychiatric disorders. Glutamate acts at two classes of receptors, ionotropic and metabotropic glutamate receptors (mGluR), the latter is classified into three group, based on receptor homology and signaling mechanisms. Among them, recent pharmacological and histochemical studies suggest that the group II mGluR (mGluR2 and mGluR3) plays crucial roles in the control of emotional states.

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Novel group II metabotropic glutamate receptor (mGluR) antagonists, 3-alkoxy-2-amino-6-fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid derivatives 11 and 12, were discovered by the incorporation of a hydroxy or alkoxyl group onto the C-3 portion of selective and potent group II mGluR agonist 5, (1R,2S,5R,6R)-2-amino-6-fluorobicyclo[3.

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The present study describes the pharmacological profile of (1R,2R,3R,5R,6R)-2-Amino-3-(3,4-dichlorobenzyloxy)-6-fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (MGS0039), a novel group II mGluR antagonist.

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The sequential Sonogashira reaction and the cyclization reaction of various 2-iodoanilines and terminal alkynes in the presence of a palladium catalyst and tetrabutylammonium fluoride (TBAF) gave the corresponding 2-substituted indoles in good yields.

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The reaction of ethyl 2-ethynylphenylcarbamate derivative with alkenes in the presence of a palladium(II) catalyst, copper dichloride and tetrabutylammonium fluoride (TBAF) produced 2-substituted 3-ethenylindoles during refluxing. The intramolecular cyclization reaction of ethyl 2-ethynylphenylcarbamates, which have an ethenyl part in the ethynyl group, was also used to produce carbazole derivatives.

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Furostifoline, a furo[3,2-a]carbazole alkaloid, was synthesized in 10% overall yield in four steps from 2-acetyl-3-bromofuran. The key step of this synthesis was the 2-substituted indole formation with tetrabutylammonium fluoride (TBAF) from 2-(2-propenyl)-3-((2-ethoxycarbonylamino)phenylethynyl)furan, which was easily prepared from ethyl 2-ethynylphenylcarbamate with 3-bromo-2-(2-propenyl)furan by the Sonogashira reaction.

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