Discovery of ((1S,3R)-1-isopropyl-3-((3S,4S)-3-methoxy-tetrahydro-2H-pyran-4-ylamino)cyclopentyl)(4-(5-(trifluoromethyl)pyridazin-3-yl)piperazin-1-yl)methanone, PF-4254196, a CCR2 antagonist with an improved cardiovascular profile

We describe the systematic optimization, focused on the improvement of CV-TI, of a series of CCR2 antagonists. This work resulted in the identification of 10 (((1S,3R)-1-isopropyl-3-((3S,4S)-3-methoxy-tetrahydro-2H-pyran-4-ylamino)cyclopentyl)(4-(5-(trifluoromethyl)pyridazin-3-yl)piperazin-1-yl)methanone) which possessed a low projected human dose 35-45 mg BID and a CV-TI = 3800-fold.     

Design and synthesis of novel 3-(benzo[d]oxazol-2-yl)-5-(1-(piperidin-4-yl)-1H-pyrazol-4-yl)pyridin-2-amine derivatives as selective G-protein-coupled receptor kinase-2 and -5 inhibitors

G-protein-coupled receptor kinase (GRK)-2 and -5 are emerging therapeutic targets for the treatment of cardiovascular disease. In our efforts to discover novel small molecules to inhibit GRK-2 and -5, a class of compound based on 3-(benzo[d]oxazol-2-yl)-5-(1-(piperidin-4-yl)-1H-pyrazol-4-yl)pyridin-2-amine was identified as a novel hit by high throughput screening campaign. Structural modification of parent benzoxazole scaffolds by introducing substituents on phenyl displayed potent inhibitory activities toward GRK-2 and -5.     

Design and synthesis of (5-amino-1, 2, 4-triazin-6-yl)(2-(benzo[d] isoxazol-3-yl) pyrrolidin-1-yl)methanone derivatives as sodium channel blocker and anticonvulsant agents

Abstract

A series of novel (5-amino-3-substituted-1, 2, 4-triazin-6-yl) (2-(6-halo-substituted benzo[d]isoxazol-3-yl) pyrrolidin-1-yl) methanone 5a–5r was synthesized. Their anticonvulsant activities were evaluated by the maximal electroshock (MES) test and neurotoxicity was evaluated by the rotorod test. The MES test showed that (5-amino-3-phenyl-1, 2, 4-triazin-6-yl)(2-(6-fluorobenzo[d]isoxazol-3-yl) pyrrolidin-1-yl) methanone 5c was found to be the most potent compound with ED₅₀ value of 6.20?mg/kg (oral/rat) and a protective index (PI?=?ED₅₀/TD₅₀) value of >48.38, which was much higher than the PI of the reference drug phenytoin. To explain the possible mechanism of action of selected derivatives 5b, 5c, 5i and 5o, their influence on sodium channel was evaluated in vitro.     

2-(Bipiperidin-1-yl)-5-(nitroaryl)-1,3,4-thiadiazoles: Synthesis,evaluation of in vitro leishmanicidal activity,and mechanism of action

The development of novel leishmanicidal agents that are capable of being replaced by the available therapeutic options has become a priority. In the present study, the synthesis and leishmanicidal activity of a series of 5-(nitroheteroaryl-2-yl)-1,3,4-thiadiazole derivatives are described. All compounds appeared to be potent anti-leishmanial agents against both promastigote and amastigote forms of Leishmania major (L. major). Amongst the synthesized compounds, 2-([1,4′-bipiperidin]-1′-yl)-5-(5-nitrofuran-2-yl)-1,3,4-thiadiazole (IIa) and 1-(5-(1-methyl-5-nitro-1H-imidazole-2-yl)-1,3,4-thiadiazol-2-yl)-4-(piperidine-1-yl) piperidine (IIc) are the most effective. Infection index was statistically declined in the presence of all compounds. The analysis of redox-related factors revealed that exposure of L. major cells to IIa and IIc led to an increase in reactive oxygen species (ROS). Furthermore, two compounds were able to increase ROS and NO levels in infected macrophages in a dose-independent manner. In addition, we showed that these compounds induced cell death in promastigotes. Altogether, our results indicated the anti-leishmanial potential of IIa and IIc is mediated by apoptosis through an imbalance in the redox system resulting in the elevation of ROS. This new class of compound seems to hold great promise for the development of new and useful anti-leishmanial agents.     

Enzymatic and chemical preparation of 5-amino-4-chloro-2-(2,3-dihydroxyphen-1-yl)-3(2H)-pyridazinone

A hypothetical intermediate of the microbial degradation of pyrazon, 5-amino-4-chloro-2(2,3-dihydroxyphen-1-yl)-3(2H)-pyridazinone, was prepared by enzymatic and chemical treatment of 5-amino-4-chloro-2(2,3-dihydroxy-cyclohexa-4,6-dien-1-yl)-pyridazinone. The properties of the metabolite are described.     

Characterization of 1-(2-[18F] fluoro-3-pyridyl)-4-(2-isopropyl-1-oxo- isoindoline-5-yl)-5-methyl-1H-1,2,3-triazole, a PET ligand for imaging the metabotropic glutamate receptor type 1 in rat and monkey brains

Neurovascular degeneration contributes to the pathogenesis of Alzheimer's disease (AD). Because erythropoietin (EPO) promotes endothelial regeneration, we investigated the therapeutic effects of EPO in animal models of AD. In aged Tg2576 mice, EPO receptors (EPORs) were expressed in the cortex and hippocampus. Tg2576 mice were treated with daily injection of EPO (5000 IU/kg/day) for 5 days. At 14 days, EPO improved contextual memory as measured by fear-conditioning test. EPO enhanced endothelial proliferation and the level of synaptophysin expression in the brain. EPO also increased capillary density, and decreased the level of the receptor for advanced glycation endproducts (RAGE) in the brain, while decreasing in the amount of amyloid plaque and amyloid-β (Aβ). In cultured human endothelial cells, EPO enhanced angiogenesis and suppressed the expression of the RAGE. These results show that EPO improves memory and ameliorates endothelial degeneration induced by Aβ in AD models. This pre-clinical evidence suggests that EPO may be useful for the treatment of AD.     

Discovery of (R)-N-(3-(7-methyl-1H-indazol-5-yl)-1-(4-(1-methylpiperidin-4-yl)-1-oxopropan-2-yl)-4-(2-oxo-1,2-dihydroquinolin-3-yl)piperidine-1-carboxamide (BMS-742413): A potent human CGRP antagonist with superior safety profile for the treatment of migraine through intranasal delivery

Calcitonin gene-related peptide (CGRP) receptor antagonists have been shown to be efficacious as abortive migraine therapeutics with the absence of cardiovascular liabilities that are associated with triptans. Herein, we report the discovery of a highly potent CGRP receptor antagonist, BMS-742413, with the potential to provide rapid onset of action through intranasal delivery. The compound displays excellent aqueous solubility, oxidative stability, and toxicological profile. BMS-742413 has good intranasal bioavailability in the rabbit and shows a robust, dose-dependent inhibition of CGRP-induced increases in marmoset facial blood flow.     

Discovery of 2-(4-((1H-1,2,4-triazol-1-yl)methyl)-5-(4-bromophenyl)-1-(2-chlorophenyl)-1H-pyrazol-3-yl)-5-tert-butyl-1,3,4-thiadiazole (GCC2680) as a potent,selective and orally efficacious cannabinoid-1 receptor antagonist

Structure–activity relationship studies in a series of diarylpyrazolyl thiadiazoles identified cannabinoid-1 receptor antagonists with excellent potency and selectivity. Based on its exceptional in vivo efficacy in animal models and its favorable pharmacokinetic and toxicological profiles, 2-(4-((1H-1,2,4-triazol-1-yl)methyl)-5-(4-bromophenyl)-1-(2-chlorophenyl)-1H-pyrazol-3-yl)-5-tert-butyl-1,3,4-thiadiazole (GCC2680) was selected as a preclinical candidate for the treatment of obesity.     

Optically active antifungal azoles: synthesis and antifungal activity of (2R,3S)-2-(2,4-difluorophenyl)-3-(5-[2-[4-aryl-piperazin-1-yl]-ethyl]-tetrazol-2-yl/1-yl)-1-[1,2,4]-triazol-1-yl-butan-2-ol

A series of (2R,3S)-2-(2,4-difluorophenyl)-3-(5-[2-[4-aryl-piperazin-1-yl]-ethyl]-tetrazol-2-yl)-1-[1,2,4]-triazol-1-yl-butan-2-ol (11a-n) and (2R,3S)-2-(2,4-difluorophenyl)-3-(5-[2-[4-aryl-piperazin-1-yl]-ethyl]-tetrazole-1-yl)-1-[1,2,4]-triazol-1-yl-butan-2-ol (12a-n) has been synthesized. The antifungal activity of compounds was evaluated by in vitro agar diffusion and broth dilution assay. Compounds 11d and its positional isomer 12d having 3-trifluoromethyl substitution on the phenyl ring of piperazine demonstrated significant antifungal activity against variety of fungal cultures (Candida spp. C. neoformans and Aspergillus spp.). The compound 12d showed MIC value of 0.12 microg/mL for C. albicans, C. albicans V-01-191A-261 (resistant strain); 0.25 microg/mL for C. tropicalis, C. parapsilosis ATCC 22019 and C. krusei and MIC value of 0.5 microg/mL for C. glabrata, C. krusei ATCC 6258, which is comparable to itraconazole and better than fluconazole. Further, compound 11d showed significant activity (MIC; 0.25-0.5 microg/mL) against Candida spp. and strong anticryptococcal activity (MIC; 0.25 microg/mL) against C. neoformans.     

Synthesis of novel 3-(1-(1-substituted piperidin-4-yl)-1H-1,2,3-triazol-4-yl)-1,2,4-oxadiazol-5(4H)-one as antifungal agents

A novel series of 1,2,3 triazole compounds possessing 1,2,4 oxadiazole ring were efficiently synthesized. Synthesized compounds were evaluated for their in vitro antifungal activities using standard cup plate method. SAR for the series has been developed by comparing their MIC values with miconazole and fluconazole. Compound 11a from the series was more potent than miconazole against Candida albicans (MIC-20) and Aspergillus flavus (MIC-10) whereas equipotent with miconazole against Fusarium oxysporum (MIC-25) and Aspergillus niger (MIC-12.5). Also compound 11h was more potent than miconazole against Candida albicans (MIC-20) and Aspergillus niger (MIC-10) and equipotent with miconazole against Fusarium oxysporum. Compound 11h was equipotent with fluconazole against Aspergillus niger (MIC-10).     

(3,3-Difluoro-pyrrolidin-1-yl)-[(2S,4S)-(4-(4-pyrimidin-2-yl-piperazin-1-yl)-pyrrolidin-2-yl]-methanone: A potent,selective, orally active dipeptidyl peptidase IV inhibitor

A series of 4-substituted proline amides was synthesized and evaluated as inhibitors of dipeptidyl pepdidase IV for the treatment of type 2 diabetes. (3,3-Difluoro-pyrrolidin-1-yl)-[(2S,4S)-(4-(4-pyrimidin-2-yl-piperazin-1-yl)-pyrrolidin-2-yl]-methanone (5) emerged as a potent (IC₅₀ = 13 nM) and selective compound, with high oral bioavailability in preclinical species and low plasma protein binding. Compound 5, PF-00734200, was selected for development as a potential new treatment for type 2 diabetes.     

3-[2-Amino-2-imidazolin-4(5)-yl]alanine (enduracididine) and 2-[2-amino-2-imidazolin-4(5)-yl] acetic acid in seeds of Lonchocarpus sericeus

3-[2-Amino-2-imidazolin-4(5)-yl]alanine (enduracididine) and 2-[2-amino-2-imidazolin-4(5)-yl] acetic acid have been isolated from seeds of Lonchocarpus sericeus. The concentration of each compound was ca 0.5 % of the fresh seed weight.     

Discovery,synthesis and characterization of a series of (1-alkyl-3-methyl-1H-pyrazol-5-yl)-2-(5-aryl-2H-tetrazol-2-yl)acetamides as novel GIRK1/2 potassium channel activators

The present study describes the discovery and characterization of a series of 5-aryl-2H-tetrazol-3-ylacetamides as G protein-gated inwardly-rectifying potassium (GIRK) channels activators. Working from an initial hit discovered during a high-throughput screening campaign, we identified a tetrazole scaffold that shifts away from the previously reported urea-based scaffolds while remaining effective GIRK1/2 channel activators. In addition, we evaluated the compounds in Tier 1 DMPK assays and have identified a (3-methyl-1H-pyrazol-1-yl)tetrahydrothiophene-1,1-dioxide head group that imparts interesting and unexpected microsomal stability compared to previously-reported pyrazole head groups.     

2-Substituted 4-, 5-, and 6-[(1E)-3-oxo-3-phenylprop-1-en-1-yl]pyridazin-3(2H)-ones and 2-substituted 4,5-bis[(1E)-3-oxo-3-phenylprop-1-en-1-yl]pyridazin-3(2H)-ones as potent platelet aggregation inhibitors: design, synthesis, and SAR studies

A set of regioisomeric 2-substituted pyridazin-3(2H)-ones containing a 3-oxo-3-phenylprop-1-en-1-yl fragment at either position 4, 5 or 6 and 2-substituted pyridazin-3(2H)-ones containing the same fragment both at positions 4 and 5 have been synthesized and evaluated as antiplatelet agents. The study allows the identification of a new highly potent platelet aggregation inhibitor (4c).     

Interactions of N-{[2-(4-phenyl-piperazin-1-yl)-ethyl]-phenyl}-2-aryl-2-yl-acetamides and 1-{[2-(4-phenyl-piperazin-1-yl)-ethyl]-phenyl}-3-aryl-2-yl-ureas with dopamine D2 and 5-hydroxytryptamine 5HT(1A) receptors

It is suggested that the ratio of dopamine D(2) to 5-hydroxytryptamine 5-HT(1A) activity is an important parameter that determines the efficiency of antipsychotic drugs. Here we present the synthesis of N-{[2-(4-phenyl-piperazin-1-yl)-ethyl]-phenyl}-2-aryl-2-yl-acetamides and 1-{[2-(4-phenyl-piperazin-1-yl)-ethyl]-phenyl}-3-aryl-2-yl-ureas and their structure-activity relationship studies on dopamine D(2) and 5-hydrohytryptamine 5-HT(1A) receptors. It was shown that ligand selectivity and affinity strongly depends on their topology and the presence of a pyridyl group in the head of molecules. Molecular modeling studies using homology modeling and docking simulation revealed a rational explanation for the ligand behavior. The observed binding modes and receptor-ligand interactions provided us with a clue for optimizing the optimal selectivity towards 5-HT(1A) receptors.     

Diaryldimethylpiperazine ligands with mu- and delta-opioid receptor affinity: Synthesis of (+)-4-[(alphaR)-alpha-(4-allyl-(2S,5S)-dimethylpiperazin-1-yl)-(3-hydroxyphenyl)methyl]-N-ethyl-N-phenylbenzamide and (-)-4-[(alphaR)-alpha-(2S,5S)-dimethylpiperazin-1-yl)-(3-hydroxyphenyl)methyl]-N-ethyl-N-phenylbenzamide

We have explored the synthesis of compounds that have good affinity for both mu- and delta-opioid receptors from the (alphaR,2S,5S) class of diaryldimethylpiperazines. These non-selective compounds were related to opioids that have been found to interact selectively with mu- or delta-opioid receptors as agonists or antagonists. In our initial survey, we found two compounds, (+)-4-[(alphaR)-alpha-(4-allyl-(2S,5S)-dimethylpiperazin-1-yl)-(3-hydroxyphenyl)methyl]-N-ethyl-N-phenylbenzamide (14) and its N-H relative, (-)-4-[(alphaR)-alpha-(2S,5S)-dimethylpiperazin-1-yl)-(3-hydroxyphenyl)methyl]-N-ethyl-N-phenylbenzamide (15), that interacted with delta-receptors with good affinity, and, as we hoped, with much higher affinity at mu-receptors than SNC80. The relative configuration of the benzylic position in (+)-4-[(alphaR)-alpha-(4-allyl-(2S,5S)-dimethyl-1-piperazinyl)-(3-methoxyphenyl)methyl]-benzyl alcohol (10) was determined by X-ray crystallographic analysis of a crystal that was an unresolved twin. The absolute stereochemistry of that benzylic stereogenic center was unequivocally derived by the X-ray crystallographic analysis from the two other centers of asymmetry in the molecule that were known. Those were established from the synthesis via a dipeptide cyclo-L-Ala-L-Ala in which the absolute stereochemistry was established.     

4-Hydroxy-1-[3-(5-(1,2,4-triazol-4-yl)-1H-indol-3-yl)propyl]piperidines: selective h5-HT1D agonists for the treatment of migraine

A series of 4-hydroxy-1-[3-(5-(1,2,4-triazol-4-yl)-1H-indol-3-yl)propyl] piperidines was investigated as potential selective h5-HT1D agonists for the treatment of migraine. The 4-[(N-benzyl-N-methyl)amino]methyl analog 12a was found to be a full agonist at the h5-HT1D receptor with good binding selectivity over the h5-HT1B receptor.     

1-((3S,4S)-4-amino-1-(4-substituted-1,3,5-triazin-2-yl) pyrrolidin-3-yl)-5,5-difluoropiperidin-2-one inhibitors of DPP-4 for the treatment of type 2 diabetes

A 3-amino-4-substituted pyrrolidine series of dipeptidyl peptidase IV (DPP-4) inhibitors was rapidly developed into a candidate series by identification of a polar valerolactam replacement for the lipophilic 2,4,5-trifluorophenyl pharmacophore. The addition of a gem-difluoro substituent to the lactam improved overall DPP-4 inhibition and an efficient asymmetric route to 3,4-diaminopyrrolidines was developed. Advanced profiling of a subset of analogs identified 5o with an acceptable human DPP-4 inhibition profile based on a rat PK/PD model and a projected human dose that was suitable for clinical development.     

Resolution, configurational assignment, and enantiopharmacology of 2-amino-3-[3-hydroxy-5-(2-methyl-2H- tetrazol-5-yl)isoxazol-4-yl]propionic acid, a potent GluR3- and GluR4-preferring AMPA receptor agonist

We have previously shown that (RS)-2-amino-3-[3-hydroxy-5-(2-methyl-2H-tetrazol-5-yl)isoxazol -4-yl] propionic acid (2-Me-Tet-AMPA) is a selective agonist at (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors, markedly more potent than AMPA itself, whereas the isomeric compound 1-Me-Tet-AMPA is essentially inactive. We here report the enantiopharmacology of 2-Me-Tet-AMPA in radioligand binding and cortical wedge electrophysiological assay systems, and using cloned AMPA (GluR1-4) and kainic acid (KA) (GluR5, 6, and KA2) receptor subtypes expressed in Xenopus oocytes. 2-Me-Tet-AMPA was resolved using preparative chiral HPLC. Zwitterion (-)-2-Me-Tet-AMPA was assigned the (R)-configuration based on an X-ray crystallographic analysis supported by the elution order of (-)- and (+)-2-Me-Tet-AMPA using four different chiral HPLC columns and by circular dichroism spectra. None of the compounds tested showed detectable affinity for N-methyl-D-aspartic acid (NMDA) receptor sites, and (R)-2-Me-Tet-AMPA was essentially inactive in all of the test systems used. Whereas (S)-2-Me-Tet-AMPA showed low affinity (IC(50) = 11 microM) in the [(3)H]KA binding assay, it was significantly more potent (IC(50) = 0.009 microM) than AMPA (IC(50) = 0.039 microM) in the [(3)H]AMPA binding assay, and in agreement with these findings, (S)-2-Me-Tet-AMPA (EC(50) = 0.11 microM) was markedly more potent than AMPA (EC(50) = 3.5 microM) in the electrophysiological cortical wedge model. In contrast to AMPA, which showed comparable potencies (EC(50) = 1.3-3.5 microM) at receptors formed by the AMPA receptor subunits (GluR1-4) in Xenopus oocytes, more potent effects and a substantially higher degree of subunit selectivity were observed for (S)-2-Me-Tet-AMPA: GluR1o (EC(50) = 0.16 microM), GluR1o/GluR2i (EC(50) = 0.12 microM), GluR3o (EC(50) = 0.014 microM) and GluR4o (EC(50) = 0.009 microM). At the KA-preferring receptors GluR5 and GluR6/KA2, (S)-2-Me-Tet-AMPA showed much weaker agonist effects (EC(50) = 8.7 and 15.3 microM, respectively). It is concluded that (S)-2-Me-Tet-AMPA is a subunit-selective and highly potent AMPA receptor agonist and a potentially useful tool for studies of physiological AMPA receptor subtypes.