Synthesis and biological evaluation of aryl isoxazole derivatives as metabotropic glutamate receptor 1 antagonists: a potential treatment for neuropathic pain.

Glutamate is the major excitatory neurotransmitter and known to activate the metabotropic and ionotropic glutamate receptors in the brain. Among these glutamate receptors, metabotropic glutamate receptor 1 (mGluR1) has been implicated in various brain disorders including anxiety, schizophrenia and chronic pain. Several studies demonstrated that the blockade of mGluR1 signaling reduced pain responses in animal models, suggesting that mGluR1 is a promising target for the treatment of neuropathic pain.

KST5468, a new T-type calcium channel antagonist, has an antinociceptive effect on inflammatory and neuropathic pain models.

The T-type Ca(2+) channel is a low-voltage-activated Ca(2+) channel related to nociceptive stimuli. Increases in Ca(2+) due to calcium channel activation enhance pain sensitivity through both peripheral and central pain pathways. We have developed a novel compound, KST5468, which is a T-type calcium channel antagonist.

Synthesis and biological evaluation of oxazole derivatives as T-type calcium channel blockers.

T-type calcium channel is one of therapeutic targets for the treatment of cardiovascular diseases and neuropathic pain. In this study, as a part of our ongoing efforts to develop potent T-type calcium channel blockers, we designed oxazole derivatives substituted with arylpiperazinylalkylamines. The oxazoles were synthesized in a convenient convergent synthetic method, and biologically evaluated against alpha(1G) (Ca(V)3.

Synthesis and evaluation of aryl-substituted diarylpropionitriles, selective ligands for estrogen receptor beta, as positron-emission tomographic imaging agents.

We have investigated halogen-substituted non-steroidal estrogens with selective binding affinity for the estrogen receptor beta (ERbeta that might be used for imaging the levels of this ER-subtype in breast tumors by positron emission tomography (PET). Based on diarylpropionitrile (DPN, 1a), a compound previously reported that has a 72-fold binding selectivity for ERbeta, we developed a series of DPN analogs having methyl-, hydroxyl-, and halogen substituents, including fluoroethyl and fluoropropyl groups. In competitive radiometric binding assays with [(3)H]estradiol, all of these DPN analogs showed high ERbeta/ERalpha selectivity; while the selectivity varied, in some cases it reached nearly 300-fold (RBA: ERalpha, 0.

Novel quinazolinone derivatives as 5-HT7 receptor ligands.

5-HT(7) receptor antagonists generated antidepressant-like effects in animal model and the involvement of the 5-HT(7) receptor in other pathophysiological mechanisms such as thermoregulation, learning and memory, and sleep has been highlighted by various studies. As one of our efforts to discover a new type of 5-HT(7) receptor antagonists, we here report on the synthesis and binding affinities to the 5-HT(7) receptor of the quinazolinone library 1, which was designed with various substituents (X, Y, R(1), and R(2)) on the aromatic rings and different carbon chain length. Total 85 compounds of the quinazolinone library 1 were synthesized and the binding affinities of all the synthesized compounds were obtained by radioligand binding assay for the 5-HT(7) receptor.

Comparative QSAR studies on peptide deformylase inhibitors.

Comparative quantitative structure-activity relationship (QSAR) analyses of peptide deformylase (PDF) inhibitors were performed with a series of previously published (British Biotech Pharmaceuticals, Oxford, UK) reverse hydroxamate derivatives having antibacterial activity against Escherichia coli PDF, using 2D and 3D QSAR methods, comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA), and hologram QSAR (HQSAR). Statistically reliable models with good predictive power were generated from all three methods (CoMFA r (2) = 0.957, q (2) = 0.

Asymmetric synthesis of chiral piperazinylpropylisoxazoline ligands for dopamine receptors.

The asymmetric synthesis of chiral piperazinylpropylisoxazoline analogues, (R)-(+)-1, 2 and (S)-(-)-1, 2 was accomplished through a seven-step sequence of reactions, which involved asymmetric 1,3-dipolar cycloaddition, alkyl chain extension, and reductive amination as key reactions. Chiral ligands (R)-(+)-1, 2 exhibited the higher binding affinity and selectivity for the D(3) receptor over the D(4) receptor than (S)-(-)-1, 2 ligands.

3D pharmacophore based virtual screening of T-type calcium channel blockers.

Virtual screening of the commercial databases was done by using a three dimensional pharmacophore previously developed for T-type calcium channel blockers using CATALYSTtrade mark program. Biological evaluation of 25 selected virtual hits resulted in the discovery of a highly potent compound VH04 with IC(50) value of 0.10 microM, eight times as potent as the known selective T-type calcium channel blocker, mibefradil.

Novel T-type calcium channel blockers: dioxoquinazoline carboxamide derivatives.

T-type calcium channel is one of therapeutic targets for the treatment of cardiovascular diseases and neuropathic pains. Since the withdrawal of mibefradil, a T-type calcium channel blocker, there have been a lot of efforts to develop T-type calcium channel blockers. A small molecule library of dioxoquinazoline carboxamide derivatives containing 155 compounds was designed, synthesized, and biologically evaluated for T-type calcium channel blocking activity.

In silico renal clearance model using classical Volsurf approach.

A data set of 130 diverse compounds containing both central nervous system (CNS) and non-CNS drugs was used to generate a renal clearance model using a classical Volsurf approach. Percentage renal clearance data was used as a biological input. The score plots obtained from principal component analysis and partial least-squares (PLS) analysis clearly separated high-clearance compounds from low-clearance compounds.

Classification of dopamine, serotonin, and dual antagonists by decision trees.

Dopamine antagonists (DA), serotonin antagonists (SA), and serotonin-dopamine dual antagonists (Dual) are being used as antipsychotics. A lot of dopamine and serotonin antagonists reveal non-selective binding affinity against these two receptors because the antagonists share structurally common features originated from conserved residues of binding site of the aminergic receptor family. Therefore, classification of dopamine and serotonin antagonists into their own receptors can be useful in the designing of selective antagonist for individual therapy of antipsychotic disorders.

Classification of dopamine antagonists using functional feature hypothesis and topological descriptors.

The designing of selective dopamine antagonists for their own subreceptors can be useful in individual therapy of various neuropsychiatric disorders. Three-dimensional pharmacophore hypothesis and two-dimensional topological descriptors were used to investigate and compare different classes of dopamine antagonists. The structurally diverse D(3) and D(4) antagonists above preclinical trials were selected to map common structural features of highly selective and efficacious antagonists.

KKHA-761, a potent D3 receptor antagonist with high 5-HT1A receptor affinity, exhibits antipsychotic properties in animal models of schizophrenia.

KKHA-761, 1-{4-[3-(3,4-dimethoxy-phenyl)-isoxazol-5-yl]-butyl}-4-(2-methoxy-phenyl)-piperazine, has a high affinity (Ki=3.85 nM) for human dopamine D3 receptor with about 70-fold selectivity over the human dopamine D(2L) receptor (Ki=270 nM). KKHA-761 also showed high affinity for cloned human 5-HT1A receptor (Ki=6.

Highly stereoselective synthesis of 2,5-disubstituted 3-vinylidene tetetrahydrofurans via Prins-type cyclization.

[reaction: see text]. A novel synthetic methodology for 2,5-disubstituted tetrahydrofurans having an allenyl group at the 3-position via Prins-type cyclization was developed. The reaction led to excellent selectivity and moderate to high yields.

Volsurf analysis of carbapenem antibiotics.

Classical Volsurf approach was applied to a set of 70 carbapenem compounds acting as antibiotics. Antibacterial activity of Staphylococcus aureus SG 511 and Escherichia coli 078 representing Gram positive and Gram negative bacteria, respectively, was used for the analysis. The score plots obtained from principal component analysis showed clustering of compounds according to the activity and their loading plots explained the Volsurf descriptors responsible for the separation or peculiar behaviour of these compounds.

CoMFA and CoMSIA 3D QSAR analysis on N1-arylsulfonylindole compounds as 5-HT6 antagonists.

Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) three-dimensional quantitative structure-activity relationship (3D-QSAR) studies were conducted on a series of N(1)-arylsulfonylindole compounds as 5-HT(6) antagonists. Evaluation of 20 compounds served to establish the models. The lowest energy conformer of compound 1 obtained from random search was used as template for alignment.

Synthesis and biological evaluation of novel T-type Ca2+ channel blockers.

A small molecule library of piperazinylalkylisoxazole derivatives containing about 600 compounds was designed, synthesized and evaluated for blocking effects on T-type Ca(2+) channel. Several ligands were identified to possess high inhibitory activity against the T-type Ca(2+) channel. The compound 21 with trifluoromethyl substituents at C(3)-position of phenyl group (R(1)) and C(2)-position of phenyl group (R(2)) showed the highest inhibitory activity with IC(50) value of 1.

Hologram quantitative structure activity relationship studies on 5-HT6 antagonists.

Predictive hologram quantitative structure activity relationship (HQSAR) models were developed for a series of arylsulfonamide compounds acting as specific 5-HT6 antagonists. A training set containing 48 compounds served to establish the model. The best HQSAR model was generated using atoms, bond, and connectivity as fragment distinction and 4-7 as fragment size showing cross-validated r2(q2) value of 0.

3D QSAR studies on T-type calcium channel blockers using CoMFA and CoMSIA.

Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were performed on a series of isoxazolyl compounds as a potent T-type calcium channel blockers. A set of 24 structurally similar compounds served to establish the model. Four different conformations of the most active compound were used as template structures for the alignment, three of which were obtained from Catalyst pharmacophore modeling and one by using SYBYL random search option.

First pharmacophoric hypothesis for T-type calcium channel blockers.

A three-dimensional pharmacophore model was developed for T-type calcium channel blockers in order to map common structural features of highly active compounds by using CATALYST program. In the absence of three dimensional structure based information like binding mode and unavailability of more number of specific T-type calcium channel blockers, this hypothesis which consists of three hydrophobic regions, one hydrogen bond acceptor and one positive ionizable regions will act as a valuable tool in designing new ligands. Further more after the withdrawal of mibefradil, the first marketed T-type calcium channel blocker, due to the drug-drug interactions, there is an urgent need for more work in this interest.

Synthesis and in vitro activity of novel isoxazolyl tetrahydropyridinyl oxazolidinone antibacterial agents.

A series of isoxazolyl tetrahydropyridinyl oxazolidinones with various substituents at the 3-position of the isoxazole ring have been synthesized and their in vitro antibacterial activities (MIC) were evaluated against several Gram-positive strains including the resistant strains of Staphyloccus and Enterococcus, such as MRSA and VRE. One of the most potent compounds synthesized, 4f, showed comparable or better activity against selected bacterial strains than those of linezolid and vancomycin.

Pharmacological actions of a novel and selective dopamine D3 receptor antagonist, KCH-1110.

1-(2-ethoxy-phenyl)-4-[3-(3-thiophen-2-yl-isoxazolin-5-yl)-propyl]-piperazine (KCH-1110), has a high affinity for human dopamine D3 (hD3) receptor (Ki=1.28 nM) with about 90-fold selectivity over the human dopamine D2L (hD2L) receptor. Antipsychotic or antidopaminergic activity of KCH-1110 was investigated in the models for the positive symptoms of schizophrenia, apomorphine-induced climbing and cocaine-induced hyperlocomotion, in mice.

The 3D-QSAR study of antitumor arylsulfonylimidazolidinone derivatives by CoMFA and CoMSIA.

Three-dimensional quantitative structure-activity relationship (3D-QSAR) studies for a series of arylsulfonylimidazolidinone derivatives having antitumor activity were conducted using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). The in vitro cytotoxicity against human lung carcinoma (A549) exhibited a strong correlation with steric and electrostatic factors of the molecules. Four different types of models have been built using CoMFA and CoMSIA method with AM1 charge or Gasteiger-Huckel charge.

Synthesis of novel 2,6-disubstituted-3,4-dimethylidene tetrahydropyrans via Prins-type cyclization.

Synthesis of novel substituted tetrahydropyrans with adjacent exo-methylene groups at the C3 and C4 positions via Prins-type cyclization has been described.

Synthesis and in vitro activity of new methylenepiperidinyl and methylenepyrrolidinyl oxazolidinone antibacterial agents.

We have prepared and evaluated the antibacterial activities of a series of substituted methylenepiperidinyl and methylenepyrrolidinyl oxazolidinones against several gram-positive strains including the resistant strains of Staphyloccus and Enterococcus, such as MRSA, CRSA, MSSA and VRE. Some of them showed comparable or superior in vitro activities (MIC) to vancomycin.