Copper-Catalyzed Synthesis of Unsymmetrical Diorganyl Chalcogenides (Te/Se/S) from Boronic Acids under Solvent-Free Conditions.

The efficient and mild copper-catalyzed synthesis of unsymmetrical diorganyl chalcogenides under ligand- and solvent-free conditions is described. The cross-coupling reaction was performed using aryl boric acids and 0.5 equiv. of diorganyl dichalcogenides (Te/Se/S) in the presence of 3 mol % of CuI and 3 equiv. of DMSO, under microwave irradiation. This new protocol allowed the preparation of several unsymmetrical diorganyl chalcogenides in good to excellent yields.

Succinobucol, a Non-Statin Hypocholesterolemic Drug, Prevents Premotor Symptoms and Nigrostriatal Neurodegeneration in an Experimental Model of Parkinson's Disease.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by non-motor and motor disabilities. This study investigated whether succinobucol (SUC) could mitigate nigrostriatal injury caused by intranasal 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration in mice. Moreover, the effects of SUC against MPTP-induced behavioral impairments and neurochemical changes were also evaluated. The quantification of tyrosine hydroxylase-positive (TH+) cells was also performed in primary mesencephalic cultures to evaluate the effects of SUC against 1-methyl-4-phenylpyridinium (MPP+) toxicity in vitro. C57BL/6 mice were treated with SUC (10 mg/kg/day, intragastric (i.g.)) for 30 days, and thereafter, animals received MPTP infusion (1 mg/nostril) and SUC treatment continued for additional 15 days. MPTP-infused animals displayed significant non-motor symptoms including olfactory and short-term memory deficits evaluated in the olfactory discrimination, social recognition, and water maze tasks. These behavioral impairments were accompanied by inhibition of mitochondrial NADH dehydrogenase activity (complex I), as well as significant decrease of TH and dopamine transporter (DAT) immunoreactivity in the substantia nigra pars compacta and striatum. Although SUC treatment did not rescue NADH dehydrogenase activity inhibition, it was able to blunt MPTP-induced behavioral impairments and prevented the decrease in TH and DAT immunoreactivities in substantia nigra (SN) and striatum. SUC also suppressed striatal astroglial activation and increased interleukin-6 levels in MPTP-intoxicated mice. Furthermore, SUC significantly prevented the loss of TH+ neurons induced by MPP+ in primary mesencephalic cultures. These results provide new evidence that SUC treatment counteracts early non-motor symptoms and neurodegeneration/neuroinflammation in the nigrostriatal pathway induced by intranasal MPTP administration in mice by modulating events downstream to the mitochondrial NADH dehydrogenase inhibition.

Decreased forelimb ability in mice intracerebroventricularly injected with low dose 6-hydroxidopamine: A model on the dissociation of bradykinesia from hypokinesia.

Bradykinesia and hypokinesia represent well-known motor symptoms of Parkinson's disease (PD). While bradykinesia (slow execution of movements) is present in less affected PD patients and aggravates as the disease severity increases, hypokinesia (reduction of movement) seems to emerge prominently only in the more affected patients. Here we developed a model based on the central infusion of low dose (40µg) 6-hydroxydopamine (6-OHDA) in mice in an attempt to discriminate bradykinesia (accessed through forelimb inability) from hypokinesia (accessed through locomotor and exploratory activities). The potential beneficial effects of succinobucol against 6-OHDA-induced forelimb inability were also evaluated. One week after the beginning of treatment with succinobucol (i.p. injections, 10mg/kg/day), mice received a single i.c.v. infusion of 6-OHDA (40µg/site). One week after 6-OHDA infusion, general locomotor/exploratory activities (open field test), muscle strength (grid test), forelimb skill (single pellet task), as well as striatal biochemical parameters related to oxidative stress and cellular homeostasis (glutathione peroxidase, glutathione reductase and NADH dehydrogenases activities, lipid peroxidation and TH levels), were evaluated. 6-OHDA infusions did not change locomotor/exploratory activities and muscle strength, as well as the evaluated striatal biochemical parameters. However, 6-OHDA infusions caused significant reductions (50%) in the single pellet reaching task performance, which detects forelimb skill inability and can be used to experimentally identify bradykinesia. Succinobucol partially protected against 6-OHDA-induced forelimb inability. The decreased forelimb ability with no changes in locomotor/exploratory behavior indicates that our 6-OHDA-based protocol represents a useful tool to mechanistically study the dissociation of bradykinesia and hypokinesia in PD.

Succinobucol, a Lipid-Lowering Drug, Protects Against 3-Nitropropionic Acid-Induced Mitochondrial Dysfunction and Oxidative Stress in SH-SY5Y Cells via Upregulation of Glutathione Levels and Glutamate Cysteine Ligase Activity.

Succinobucol (succinyl ester of probucol) is a lipid-lowering compound with anti-inflammatory and antioxidant properties. Recent experimental evidence has highlighted the potential neuroprotective effects of succinobucol. In the present study, cultured neuroblastoma (SH-SY5Y) cells were used to investigate mechanisms mediating the potential protective effect of succinobucol against mitochondrial metabolic impairment and oxidative stress induced by 3-nitropropionic acid (3-NP), a succinate dehydrogenase inhibitor that has been used in experimental models of the Huntington disease (HD). 3-NP decreased cellular viability after 24 h of incubation. This decline in cellular viability was preceded by (i) reduced mitochondrial complex II activity, (ii) increased reactive species generation, (iii) decreased mitochondrial membrane potential (ΔΨm), and (iv) diminished glutathione (GSH) levels. Succinobucol pretreatment (6 days) significantly prevented 3-NP-induced loss of cellular viability, generation of reactive oxygen species, and decrease of ΔΨm. However, succinobucol pretreatment did not protect against 3-NP-induced inhibition of mitochondrial complex II activity, pointing to the mitigation of secondary events resultant from mitochondrial complex II inhibition. Succinobucol pretreatment (6 days) significantly increased (50 %) the levels of GSH in SH-SY5Y cells, and this event was paralleled by significant increases in glutamate cysteine ligase messenger RNA (mRNA) expression and activity (GCL; the first enzyme in the GSH biosynthesis). The present findings are the first to show that succinobucol increases GSH levels via upregulation of GCL activity (possibly through the activation of the nuclear (erythroid-derived 2)-related factor (Nrf2)/antioxidant response element (ARE) pathway), displaying protective effects against mitochondrial dysfunction-derived oxidative stress.

Catalytic chalcogenylation under greener conditions: a solvent-free sulfur- and seleno-functionalization of olefins via I2/DMSO oxidant system.

Herein, we report a solvent- and metal-free methodology for the alkoxy-chalcogenylation of styrenes, using molecular iodine as a catalyst, DMSO as a stoichiometric oxidant, and different nucleophiles under microwave irradiation. This eco-friendly approach afforded the desired products in good to excellent yields in only 10 min. In addition, using the same protocol, we carried out the cyclization reaction of relevant molecules, such as lapachol derivatives.

A solvent- and metal-free synthesis of 3-chacogenyl-indoles employing DMSO/I2 as an eco-friendly catalytic oxidation system.

Herein, we describe a solvent- and metal-free method for the synthesis of 3-chalcogenyl-indoles from indoles and diorganyl dichalcogenides using an equivalent amount of DMSO as an oxidant, under catalysis by molecular iodine. This mild and eco-friendly approach allowed the preparation of a wide range of 3-selenyl- and 3-sulfenyl-indoles in good to excellent yields.

Succinobucol versus probucol: higher efficiency of succinobucol in mitigating 3-NP-induced brain mitochondrial dysfunction and oxidative stress in vitro.

This study evaluated and compared the potential protective effects of probucol and succinobucol, two lipid-lowering compounds with anti-inflammatory and antioxidant properties, on oxidative stress and mitochondrial dysfunction induced by 3-nitropropionic acid (3-NP, a succinate dehydrogenase (SDH) inhibitor largely used as model of Huntington's disease) in rat brain mitochondria-enriched synaptosomes. 3-NP caused significant inhibition of mitochondrial complex II activity, induced mitochondrial dysfunction and oxidative stress. Probucol and succinobucol prevented oxidative stress, but only succinobucol was able to prevent the mitochondrial dysfunction induced by 3-NP. Succinobucol, which did not recover complex II inhibition, was able to protect against 3-NP-induced decreased of MTT reduction, indicating that SDH is not the only enzyme responsible for MTT reduction. The present findings suggest that succinobucol might be a novel strategy to slow or halt oxidative events in neurodegenerative conditions.

Chiral organoselenium-transition-metal catalysts in asymmetric transformations.

In recent years, there has been an increasing application of chiral selenium compounds as ligands in metal-catalyzed enantioselective transformations. One of the most important challenges in this field is the development of new chiral complexes (catalyst) generated from the reaction between a metal and appropriate chiral selenium-containing compounds (ligand). The vast majority of these ligands are easily synthesized in a few high-yielding synthetic steps, starting from readily available chiral amino alcohols. In this context, the advantages of using these compounds will be discussed, mainly with regard to their easy accessibility, modular nature and the formation of strong bonds with soft or, more rarely, hard metals. Important selective contributions within the field of chiral selenium complexes are examined, according to their applications. As final remarks, future developments and perspectives of the field are discussed.