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The system xc(-) antiporter is a plasma membrane transporter that mediates the exchange of extracellular l-cystine with intracellular l-glutamate. This exchange is significant within the context of the CNS because the import of l-cystine is required for the synthesis of the antioxidant glutathione, while the efflux of l-glutamate has the potential to contribute to either excitatory signaling or excitotoxic pathology. Changes in the activity of the transport system have been linked to the underlying pathological mechanisms of a variety of CNS disorders, one of the most prominent of which is its highly enriched expression in glial brain tumors. In an effort to produce more potent system xc(-) blockers, we have been using amino-3-carboxy-5-methylisoxazole propionic acid (ACPA) as a scaffold for inhibitor development. We previously demonstrated that the addition of lipophilic aryl groups to either the #4 or #5 position on the isoxazole ring markedly increased the inhibitory activity at system xc(-). In the present work a novel series of analogues has been prepared in which aryl groups have been introduced at both the #4 and #5 positions. In contrast to the competitive action of the mono-substituted analogues, kinetic analyses indicate that the di-substituted isoxazoles block system xc(-)-mediated uptake of (3)H-l-glutamate into SNB-19 cells by a noncompetitive mechanism. These new analogues appear to be the first noncompetitive inhibitors identified for this transport system, as well as being among the most potent blockers identified to date. These diaryl-isoxazoles should be of value in assessing the physiological roles and molecular pharmacology of system xc(-).

There is growing interest in using cannabinoid receptor 2 (CB2) agonists for the treatment of neuropathic pain and other indications. In continuation of our ongoing program aiming for the development of new small molecule cannabinoid ligands, we have synthesized a novel series of carbazole and γ-carboline derivatives. The affinities of the newly synthesized compounds were determined by a competitive radioligand displacement assay for human CB2 cannabinoid receptor and rat CB1 cannabinoid receptor. Functional activity and selectivity at human CB1 and CB2 receptors were characterized using receptor internalization and [35S]GTP-γ-S assays. The structure–activity relationship and optimization studies of the carbazole series have led to the discovery of a non-selective CB1 and CB2 agonist, compound 4. Our subsequent research efforts to increase CB2 selectivity of this lead compound have led to the discovery of CB2 selective compound 64, which robustly internalized CB2 receptors. Compound 64 had potent inhibitory effects on pain hypersensitivity in a rat model of neuropathic pain. Other potent and CB2 receptor–selective compounds, including compounds 63 and 68, and a selective CB1 agonist, compound 74 were also discovered. In addition, we identified the CB2 ligand 35 which failed to promote CB2 receptor internalization and inhibited compound CP55,940-induced CB2 internalization despite a high CB2 receptor affinity. The present study provides novel tricyclic series as a starting point for further investigations of CB2 pharmacology and pain treatment. Fil: Petrov, Ravil R.. University Of Montana; Estados Unidos Fil: Knight, Lindsay. Indiana University; Estados Unidos Fil: Chen, Shao Rui . University Of Texas; Estados Unidos Fil: Wager Miller, Jim. Indiana University; Estados Unidos Fil: McDaniel, Steven W.. University Of Montana; Estados Unidos Fil: Diaz, Fanny. University Of Montana; Estados Unidos Fil: Barth, Francis. Sanofi-aventis R&D; Francia Fil: Pan, Hui Lin. University Of Texas; Estados Unidos Fil: Mackie, Ken . Indiana University; Estados Unidos Fil: Cavasotto, Claudio Norberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biomedicina de Buenos Aires; Argentina Fil: Diaz, Philippe. University Of Montana; Estados Unidos

Cannabinoid CB2 receptor has emerged as a very promising target over the last decades. We have synthesized and evaluated a new fluorescent probe designated NMP6 based on 6-methoxyisatin scaffold, which exhibited selectivity and K(i) value at hCB2 of 387 nM. We have demonstrated its ability to be an effective probe for visualization of CB2 receptor binding using confocal microscopy and a flow cytometry probe for the analysis of CB2 protein expression. Furthermore, NMP6 was easily obtained in two chemical steps from commercially available building blocks.

A new series of selenium-containing acetylenic retinoids has been prepared by a copper assisted reaction of selenyl bromides with terminal alkynes bound to Wang resin.

A new series of alkynylselenide-containing retinoids has been synthesized by reacting phenylchalcogenyl halides with trimethylsilylalkynes in the presence of copper iodide.

A new series of conformationally restricted retinoids (3-aryl-3-methyl-2,3-dihydro-benzofurans) have been prepared through a palladium-catalyzed tandem cyclisation-hydride capture. The use of enantiopure BINAP-Pd catalyst allowed asymmetric synthesis of bioactive molecules.

A series of 3-aryl-2H-1-benzopyrancarboxylic acid derivatives was synthesized and evaluated as Retinoic Acid Receptor (RAR) agonists. By modifications of the 3-aryl group, we have obtained new retinoids exhibiting potent cellular differentiating activities and high affinities for RARs. Moreover, hydrogenation of the 2H-1-benzopyran ring led to the 3-(5,6,7,8-tetrahydro-5,5,8,8,-tetramethyl-naphthalen-2-yl)-3,4-dihydro-2H-1-benzopyran-7-yl carboxylic acid, characterized by a RARs binding profile.

We have prepared both enantiomers of a new retinoid ( IIa and IIb ) partly by using lipase resolution of 1-acetoxy-1-(5, 6, 7, 8 - tetrahydro - 5, 5, 8, 8-tetramethyl-2-naphthyl) ethane. Absolute configuration of resulting secondary carbinols ( 4a and 4b ) was assigned using lanthanide induced shifts NMR experiments on MTPA esters of 4a and 4b . Only the enantiomer (R-(−)- IIa ) is active on the differentiation of F9 embryonal teratocarcinoma cells (F9 cells).

A novel one-pot palladium-catalyzed cascade between 2-iodophenol, methyl bromomethylacrylate and an arylboronic acid provides an efficient access to heterocycles possessing the 3,3-disubstituted-2,3-dihydrobenzofuran skeleton via allylation/carbopalladation/Suzuki cross-coupling.