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Serotonin 5-HT3 receptors are involved in various brain functions including as an emesis target during cancer chemotherapy. We report here the development of (S)-2,3-dimethoxy-5-(3'-[(18)F]fluoropropyl)-N-(1-azabicyclo[2.2.2]oct-3-yl)benzamide ([(18)F]fesetron) as a potential PET imaging agent for serotonin 5-HT3 receptors. By radiolabeling((S)-2,3-dimethoxy-5-(3'-tosyloxypropyl)-N-(1-azabicyclo[2.2.2]oct-3-yl)benzamide) with fluorine-18, (S)-[(18)F]fesetron was obtained in 5 to 10% decay-corrected yields and with specific activities >74GBq/μmol at the end of radiosynthesis. PET imaging in rats showed low uptake of [(18)F]fesetron in the brain with retention of binding in the striatal and cerebellar regions. Using colliculi as a reference region, ratios were 3.4 for striata and 2.5 for cerebellum. Ex vivo brain PET analysis displayed binding of [(18)F]fesetron in the hippocampus, striatum and cerebellar regions. Cerebellar regions corresponded to area postrema and nucleus tract solitaris known to contain 5-HT3 receptors. Dorsal hippocampus showed the highest uptake with ratio of >17 with respect to colliculi, while area postrema and striata had ratios of >10. Thus, [(18)F]fesetron exhibited a unique binding profile to rat brain regions known to contain significant amounts of serotonin 5-HT3 receptors. However, the very low brain uptake limits its usefulness as a PET radiotracer in this animal model., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The design and synthesis of two conformationally restricted oxazabicyclo octane derivatives as GRP119 agonists is described. Derivatives of scaffold C, with syn configuration, have the best overall profiles with respect to solubility and in vivo efficacy. Compound 25a was found to have extremely potent agonistic activity and was orally active in lowering blood glucose levels in a mouse oral glucose tolerance test at a dose of 0.1 mg/kg., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Non-nucleoside inhibitors of HIV-1 reverse transcriptase (HIV-RT) are reported that incorporate a 7-indolizinylamino or 2-naphthylamino substituent on a pyrimidine or 1,3,5-triazine core. The most potent compounds show below 10 nanomolar activity towards wild-type HIV-1 and variants bearing Tyr181Cys and Lys103Asn/Tyr181Cys resistance mutations. The compounds also feature good aqueous solubility. Crystal structures for two complexes enhance the analysis of the structure-activity data., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Several bicyclic compounds, 3-azabicyclo[3.2.2]nonanes, have been prepared. The new compounds were tested for their activities against one strain of the causative organism of Malaria tropica, Plasmodium falciparum K1, which is resistant against chloroquine and pyrimethamine. In addition, their cytotoxicity and their activity against the pathogen of the East African form of sleeping sickness, Trypanosoma brucei rhodesiense, were investigated. Structure-activity relationships are discussed considering data of readily prepared compounds. For the first time, a distinct in vivo activity was observed against Plasmodium berghei in a mouse model. The active compound was further investigated., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

We have carried out computational studies on interactions of diazabicyclic amide analogs with α4β2 nAChR using homology modeling, docking and pharmacophore elucidation techniques. We have found alternative ligand binding modes in most cases. All these diverse poses exhibit the quintessential hydrogen-bonding interaction between the ligand basic nitrogen and the backbone carbonyl oxygen atom of the highly conserved Trp-149. This hydrogen bond was always found to be shorter than the one contracted by the ligand carbonyl group and a second hydrogen-bond made by the cationic center with Tyr-93 of the principal face of the protein. In most of the poses observed, cation-π interactions involved three aromatic residues located in the principal face of the protein: Trp-149, Tyr-190 and Tyr-197. The latter amino acid residue appears to often donate a hydrogen-bond to the ligand carbonyl oxygen atom. We also describe two rings of alternative receptor-based hydrogen-bond donor features equidistantly separated from the carbonyl oxygen of the highly conserved Trp-149 approximately by 5 and 8Å, respectively. These findings could be exploited to design diverse and selective novel chemical libraries for the treatment of diseases and conditions where the α4β2 nAChR is disrupted, such as Alzheimer disease, Parkinson's disease and l-dopa-induced dyskinesia (LID)., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

In an effort to prepare a fluorogenic substrate to be used in activity assays with metallo-β-lactamases, (6R,7R)-8-oxo-7-(2-oxo-2H-chromene-3-carboxamido)-3-((4-(2-oxo-2H-chromene-3-carboxamido)-phenylthio)methyl)-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid (CA) was synthesized and characterized. CA exhibited a fluorescence quantum yield (φ) of 0.0059, two fluorescence lifetimes of 3.63×10(-10) and 5.38×10(-9)s, and fluorescence intensity that is concentration-dependent. Steady-state kinetic assays revealed that CA is a substrate for metallo-β-lactamases (MβLs) L1 and CcrA, exhibiting Km and kcat values of 18μM and 5s(-1) and 11μM and 17s(-1), respectively., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

5-Nitropyrimidine analogs substituted with conformationally restricted azabicyclic amines and alcohols were prepared and evaluated their agonistic activity against human GPR119. The analogs bearing endo-azabicyclic amines and alcohols (7, 8, 11, and 12) exhibited full agonistic activities while the analogs with exo-azabicyclic amines and alcohols were proved as partial agonists (9, 10, 13, and 14) regardless of their EC(50) values. 5-Nitropyrimidine analogs with (2-fluoro-4-methylsulfonyl)phenylamino group (8, 10, 12, 14) showed more potent GPR119 activation activities than the analogs without fluorine in all cases (7, 9, 11, 13)., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

We used the modified Mannich condensation to synthesize three closely-related series of 7-alkylated 3-ABNs 1-5 viz., 7-methylated 2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ones (7-Me ABNs 1-5), 7-ethylated 2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ones (7-Et ABNs 1-5) and 7-tert-pentylated 2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ones (7-tert-pentyl ABNs 1-5). All compounds yielded good as single isomers by the use of PPA·SiO(2) as a heterogeneous Bronsted acidic catalyst. The 1D, 2D NMR, and single-crystal XRD interpretations unambiguously characterized the stereochemistry of the synthesized compounds. In solution as well as solid-state, all compounds exist in the twin-chair conformation with equatorial orientations of all substitutions, despite their nature and positions. The chemical methods viz., DPPH, reducing power, and phospho-molybdenum methods identified some of the target curcumin analogs as active compounds. Among them, 7-Me ABN 4 (7-methyl-2,4-bis(3-methoxy-4-hydroxyphenyl)-3-azabicyclo[3.3.1]nonan-9)-one exerted the best antioxidant profile that comparable to standard l-ascorbic acid, α-tocopherol and curcumin. Hence, we evaluated further for its intracellular ROS inhibition potency on RAW 264.7 macrophage cells, and found to be effective as well as non-toxic at 100 μM., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

This Paper describes the continued optimization of an MLPCN probe molecule M(1) antagonist (ML012) through an iterative parallel synthesis approach. After several rounds of modifications of the parent compound, we arrived at a new azetidine scaffold that displayed improved potency while maintaining a desirable level of selectivity over other muscarinic receptor subtypes. Data for representative molecules 7w (VU0452865) and 12a (VU0455691) are presented., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A series of N-substituted 7-azabicyclo[2.2.1]heptanes (12-17 and 22-25) and similarly substituted pyrrolidines (32-36 and 41-44) were synthesized as sterically-reduced, achiral analogs of adamantane- and trishomocubane-derived σ ligands. In vitro competition binding assays against σ receptors revealed that arylalkyl N-substituents conferred selectivity for the σ(2) subtype, while alicyclic or polycarbocyclic substituents imparted high affinity for both subtypes. The σ(2) binding and subtype selectivities of N-arylalkyl-7-azanorbornanes was generally greater than the analogously-substituted pyrrolidines, indicating that steric bulk and conformational restriction around the nitrogen atom are likely important for subtype discrimination., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

This letter describes the discovery and synthesis of a series of octahydropyrrolo[3,4-c]pyrrole based selective histamine hH4 receptor antagonists. The amidine compound 20 was found to be a potent and selective histamine H4 receptor antagonist with moderate clearance and a high volume of distribution., (Copyright © 2011. Published by Elsevier Ltd.)

2-[(2,4-Diaryl-3-azabicyclo[3.3.1]nonan-9-ylidene)hydrazono]-4-phenyl-2,3-dihydrothiazoles (3a-3k) have been synthesized by the cyclization of 2-[(2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-one thiosemicarbazones with phenacyl bromide and characterized by analytical (melting point and elemental analysis) and spectral (IR, (1)H NMR, (13)C NMR, D(2)O exchange, NOESY and mass) techniques. The novel Hantzsch products (3a-3k) were screened for their in vitro antibacterial and antifungal activities against some selected microorganisms. Structure activity relationship (SAR) for the reported compounds was studied by comparing their MIC values with standard drugs (Streptomycin and Amphotericin B). The results show that 3e against Escherichia coli and Cryptococcus neoformans3i against Bacillus Subtilis, 3b against Aspergillus flavus, and 3k against Rhizopus sp. were found to show significant growth inhibition., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

In looking for a novel achiral μ opioid receptor antagonist for the treatment of pruritus, we designed and synthesised azabicyclo[3.1.0]hexane compounds as a new class of opioid ligand. During optimisation, an addition of a single methyl resulted in a 35-fold improvement in binding. An early example from the series had excellent μ opioid receptor antagonist antagonist activity and was very effective in an in vivo pruritus study., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Bicyclic piperazine derivatives were synthesized as conformationally constrained analogs of N-alkyl piperazines and were found to be potent CB1 receptor agonists. The CB1 receptor agonist activity was dependent upon the absolute configuration of the chiral center of the bicyclic ring system. Although the conformational constraint did not protect the compounds from metabolism by N-dealkylation, several bicyclic analogs were found to be more potent than the unconstrained lead compound. Compound 8b demonstrated potent antinociceptive activity in vivo., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Antagonists of the corticotropin-releasing factor (CRF) neuropeptide may prove effective in treating stress and anxiety related disorders. In an effort to identify antagonists with improved physico-chemical properties a new series of CRF(1) antagonists were designed to substitute the propyl groups at the C7 position of the pyrazolo[1,5-a]pyrimidine core of 1 with heterocycles. Compound (S)-8d was identified as a high affinity ligand with a pK(i) value of 8.2 and a functional CRF(1) antagonist with pIC(50) value of 7.0 in the in vitro CRF ACTH production assay., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

We report the synthesis of a series of [3.2.1]azabicyclic biaryl ethers as selective agonists of alpha3- and alpha6-containing nicotinic receptors. In particular, compound 17a from this series is a potent alpha3beta4 and alpha6/4beta4 receptor agonist in terms of both binding and functional activity. Compound 17a also shows potent in vivo activity in CNS-mediated animal models that are sensitive to antipsychotic drugs. Compound 17a may thus be a useful tool for studying the role of alpha3beta4 and alpha6/4beta4 nicotinic receptors in CNS pharmacology.

Endocannabinoids (eCBs) are endogenous neuromodulators of synaptic transmission. Their dysfunction may cause debilitating disorders of diverse clinical manifestation. For example, drug addiction, lack of sex desire, eating disorders, such as anorexia or bulimia and dyssomnias. eCBs also participate in the regulation of core temperature and pain perception. In this context, it is important to recognize the utility of cannabinoid receptor 1 (CB1R) agonists, natural as Delta(9)-tetrahydrocannabinol (THC) or synthetic as Nabilone as useful drugs to alleviate this kind of patients' suffering. Therefore, we have developed a new drug, (R,Z)-18-((1S,4S)-5-methyl-2,5-diazabicyclo[2.2.1]heptan-2-yl)-18-oxooctadec-9-en-7-yl phenylacetate (PhAR-DBH-Me), that appears to bind and activate the CB1R. This diazabicyclic amide was synthesized from phenylacetylricinoleic acid and (1S,4S)-2,5-diazabicyclo[2.2.1]heptane. To test its cannabinergic properties we evaluated its effects on core temperature, pain perception, and the sleep-waking cycle of rats. Results indicate that 20 and 40mg/kg of PhAR-DBH-Me readily reduced core temperature and increased pain perception threshold. In addition, 20mg/kg increased REM sleep in otherwise normal rats. All these effects were prevented or attenuated by AM251, a CB1R antagonist. Place preference conditioning studies indicated that this molecule does not produce rewarding effects. These results strongly support that PhAR-DBH-Me possesses cannabinoid activity without the reinforcement effects., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Libraries of 1-methyl-2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ones/oximes/O-methyloximes 1-14/15-28/29-42 and 7-methyl-2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ones/oximes/O-methyloximes 43-48/49-54/55-60 were synthesized and their stereochemistry was established by 1D/2D NMR spectral and single crystal XRD studies. All the synthesized oximes and oxime ethers were screened for their in vitro antimicrobial activity against a panel of pathogenic bacteria (Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa) and fungi (Candida albicans, Candida parapsilosis, Aspergillus niger and Cryptococcus neoformans) using Gentamicin and Fluconazole as standards, respectively. From the SAR profile, the lead molecules were identified., (Copyright 2010 Elsevier Ltd. All rights reserved.)

The synthesis and biochemical evaluation of novel cyanothiazolidine inhibitors of dipeptidyl peptidase 4 (DPP4) is described. Their main structural feature is a constrained bicyclic core that prevents the intramolecular formation of inactive cyclic species. The inhibitors show good to moderate biochemical potency against DPP4 and display distinct selectivity profiles towards DPP7, DPP8 and DPP9 depending on their substitution.

PR04.MZ was designed as a highly selective dopamine transporter inhibitor, derived from natural cocaine. Its binding profile indicates that [(11)C]PR04.MZ may be suited as a PET radioligand for the non-invasive exploration of striatal and extrastriatal DAT populations. As a key feature, its structural design facilitates both, labelling with fluorine-18 at its terminally fluorinated butynyl moiety and carbon-11 at its methyl ester function. The present report concerns the efficient [(11)C]MeI mediated synthesis of [(11)C]PR04.MZ from an O-desmethyl precursor trifluoroacetic acid salt with Rb(2)CO(3) in DMF in up to 95+/-5% labelling yield. A preliminary muPET-experiment demonstrates the reversible, highly specific binding of [(11)C]PR04.MZ in the brain of a male Sprague-Dawley rat.

New series of 2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-one thiosemicarbazones (9-16) obtained from the corresponding 2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ones (1-8) upon cyclization with ethylbromoacetate in the presence of sodium acetate-acetic acid buffer afforded novel 2-[(2,4-diaryl-3-azabicyclo[3.3.1]nonan-9-ylidene)hydrazono]-1,3-thiazolidin-4-ones (17-24). The synthesized compounds have been characterized by their elemental, analytical and spectral studies. Besides, the reported compounds were screened for their antibacterial and antifungal activities against a spectrum of microbial organisms. These studies proved that compounds 11/18/20/23 against Staphylococcus aureus, 19/20/24 against Salmonella typhi show maximum inhibition potency at low concentration (6.25microg/ml) whereas 18/19 against Candida albicans and 19/20/21 against Rhizopus sp. showed beneficial antifungal activity at minimum concentration.

The synthesis and structure-activity relationship (SAR) of a novel series of 3-(imidazolyl methyl)-3-aza-bicyclo[3.1.0]hexan-6-yl)methyl ethers, derived from a high throughput screening (HTS), are described. Subsequent optimization led to identification of potent, metabolically stable and orally available mGluR2 positive allosteric modulators (PAMs).

A novel alpha7 nAChR agonist, N-[(3R,5R)-1-azabicyclo[3.2.1]oct-3-yl]furo[2,3-c]pyridine-5-carboxamide (3a, PHA-709829), has been identified for the potential treatment of cognitive deficits in schizophrenia. The compound shows potent and selective alpha7 in vitro activity, excellent brain penetration, good rat oral bioavailability and robust in vivo efficacy in a rat auditory sensory gating model.