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A new method was developed for the synthesis of 4-chalcogenyl-1H-isochromen-1-ones through the 6-endo-dig electrophilic cyclization of 2-alkynylaryl esters and diorganyl dichalcogenides under ultrasound irradiation. The reactions were performed under mild conditions, using Oxone as a green oxidant to promote the cleavage of the chalcogen-chalcogen bond in diorganyl diselenides and ditellurides to generate electrophilic species in situ. A total of 25 compounds were selectively obtained after 30-70 min, in good to excellent yields (74-95%). This procedure was extended to prepare 5H-selenopheno[3,2-c]isochromen-5-ones. Additionally, for the first time, the 4-chalcogenyl-1H-isochromen-1-ones were used as substrates in the thionation reaction, using Lawesson's reagent and microwave irradiation under solvent-free conditions, obtaining the thio derivatives in yields of up to 99% in only 15 min.

We describe our results for the synthesis of 2′-(1,2,3-triazoyl)-acetophenones by copper catalyzed azide–alkyne cycloaddition of 2′-azidoacetophenone with alkynes. The corresponding 2′-(1,2,3-triazoyl)-acetophenones were obtained in moderate to excellent yields and according to our experiments, it was observed that ultrasound accelerates the reaction compared to conventional heating. In addition, the obtained compounds were screened by molecular docking for their possible inhibitory effect on the activity of monoamine oxidase (MAO), an enzyme responsible for the degradation of monoamine neurotransmitters. Three compounds were selected and presented an inhibitory effect on both MAO-A and B isoform activities in vitro. These new MAO inhibitors may be of interest to treat monoamine deficit related-neuropsychiatric disorders, such as depression and Parkinson's disease.

We describe herein an alternative and transition-metal-free procedure for the access of benzo[b]chalcogenophenes fused to selenophenes via intramolecular cyclization of 1,3-diynes. This efficient protocol involves a double cyclization of 1,3-diynyl chalcogen derivatives promoted by the electrophilic species of organoselenium generated in situ by the oxidative cleavage of the Se-Se bond of dibutyl diselenide using Oxone® in acetonitrile as solvent in an open-flask at 80 °C. In this study, 15 selenophenes with broad substrate scope were prepared in moderate to excellent yields (55-98%) with short reaction times (0.5-3.0 h).

Pyrazoles represent a significant class of heterocyclic compounds that exhibit pharmacological properties. The present study aimed to investigate the antioxidant potential of pyrazol derivative compounds in brain of mice in vitro and the effect of pyrazol derivative compounds in the oxidative damage and toxicity parameters in mouse brain and plasma of mice. The compounds tested were 3,5-dimethyl-1-phenyl-4-(phenylselanyl)-1H-pyrazol (1a), 3,5-dimethyl-4-(phenylselanyl)-1H-pyrazole (2a), 4-((4-methoxyphenyl)selanyl)-3,5-dimethyl-1-phenyl-1H-pyrazole (3a), 4-((4-chlorophenyl)selanyl)-3,5-dimethyl-1-phenyl-1H-pyrazole (4a), 3,5-dimethyl-1-phenyl-4-(phenylthio)-1H-pyrazole (1b), 3,5-dimethyl-4-(phenylthio)-1H-pyrazole (2b), 4-((4-methoxyphenyl)thio)-3,5-dimethyl-1-phenyl-1H-pyrazole (3b), 4-((4-chlorophenyl)thio)-3,5-dimethyl-1-phenyl-1H-pyrazole (4b), and 3,5-dimethyl-1-phenyl-1H-pyrazole (1c). In vitro, 4-(arylcalcogenyl)-1H-pyrazoles, at low molecular range, reduced lipid peroxidation and reactive species in mouse brain homogenates. The compounds also presented ferric-reducing ability as well nitric oxide-scavenging activity. Especially compounds 1a, 1b, and 1c presented efficiency to 1,1-diphenyl-2-picryl-hydrazyl-scavenging activity. Compounds 1b and 1c presented 2,20 -azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)-scavenging activity. In vivo assays demonstrated that compounds 1a, 1b, and 1c (300 mg/kg, intragastric, a single administration) did not cause alteration in the of δ-aminolevulinic acid dehydratase activity, an enzyme that exhibits high sensibility to prooxidants situations, in the brain, liver, and kidney of mice. Compound 1c reduced per se the lipid peroxidation in liver and brain of mice. Toxicological assays demonstrate that compounds 1a, 1b, and 1c did not present toxicity in the aspartate aminotransferase, alanine aminotransferase, urea, and creatinine levels in the plasma. In conclusion, the results demonstrated the antioxidant action of pyrazol derivative compounds in in vitro assays. Furthermore, the results showed low toxicity of compounds in in vivo assays.

We described here our results on the use of thiourea as a ligand in the copper catalysed azide-alkyne cycloaddition (CuAAC) of 2-azidobenzaldehyde with alkynes. Reactions were performed reacting 2-azidobenzaldehyde with a range of terminal alkynes using 10 mol % of copper iodide as a catalyst, 20 mol % of thiourea as a ligand, triethylamine as base, DMSO as solvent at 100 °C under nitrogen atmosphere. The corresponding 2-(1H-1,2,3-triazoyl)-benzaldehydes (2-TBH) were obtained in moderated to excellent yields and according our experiments, the use of thiourea decreases the formation of side products. The obtained compounds were screened for their binding affinity with multiple therapeutic targets of AD by molecular docking: β-secretase (BACE), glycogen synthase kinase (GSK-3β) and acetylcholinesterase (AChE). The three compounds with highest affinity, 5 a (2-(4-phenyl-1H-1,2,3-triazol-1-yl)benzaldehyde), 5 b (2-(4-(p-tolyl)-1H-1,2,3-triazol-1-yl)benzaldehyde), and 5 d (2-(4-(4-(tert-butyl)phenyl)-1H-1,2,3-triazol-1-yl)benzaldehyde) were selected and evaluated on its antioxidant effect, in view of select the most promising one to perform the in vivo validation. Due the antioxidant potential ally to the affinity with BACE, GSK-3β and AChE, compound 5 b was evaluated in a mouse model of AD induced by intracerebroventricular injection of streptozotocin (STZ). Our results indicate that 5 b (1 mg/kg) treatment during 20 days is able to reverse the cognitive and memory impairment induced by STZ trough the modulation of AChE activity, amyloid cascade and GSK-3β expression.

We describe here our results from the copper-catalyzed three component reaction of 2-azidobenzaldehyde, anthranilamide and terminal alkynes, using Et3N as base, and DMSO as solvent. Depending on the temperature and amount of Et3N used in the reactions, 1,2,3-triazolyl-quinazolinones or 1,2,3-triazolyl-dihydroquinazolinone could be obtained. When the reactions were performed at 100 °C using 2 equivalents of Et3N, 1,2,3-triazolyl-dihydroquinazolinone was formed in 82% yield, whereas reactions carried out at 120 °C using 1 equivalent of Et3N provided 1,2,3-triazolyl-quinazolinones in moderate-to-good yields.

4-(Arylchalcogenyl)-1H-pyrazoles containing selenium or sulfur (0.001–50 mg/kg) were investigated regarding the intragastric route effect (ig) administration on nociception in mice. In this study, nociception and inflammation were induced by chemical agents such as formalin (0.92%), sodium l-glutamate 1-hydrate (20 μmol), croton oil (2.5%), acetic acid (1.6%) and thermic model with a hot plate test. Compounds 1a–c had the ability to reduce licking time in both phases (neurogenic and inflammatory) of the formalin test and glutamate. Only compounds 1a and 1b had the ability to reduce the number of abdominal writhes caused by acetic acid. The same was observed with the positive control celecoxib. To evaluate the possible anti-inflammatory activity of compounds 1a–c, the induction of paw edema by formalin and ear edema by croton oil was performed. For the inflammation induced by formalin, significant effects were observed from the dose of 0.1 mg/kg (1a–b) and 10 mg/kg (1c). In the ear edema test, it can be observed that only compound 1a had a significant effect. In the hotplate test, all the compounds had the ability to reduce the latency time. The results demonstrated that acute antinociceptive and anti-inflammatory effects of 4-(arylchalcogenyl)-1H-pyrazoles 1a is better than compared with the compound 1b and 1c in mice. This resulted in these molecules attracting the interest of researchers to perform future studies to develop new drugs to treat pain and inflammatory clinical conditions.

Polysaccharide-based materials have been claimed as efficient supports for different species used in catalysis, such as transition metal ions. Overall, the immobilization of metal ions on these materials brings several attractive aspects in terms of economy and catalytic activity. In this study, we demonstrated the facile immobilization of Cu2+ ions on alginate-based microspheres (Alg–Cu2+) via a straightforward ion exchange process. The prepared microspheres were characterized in detail by different techniques. As assessed, the ion-exchange process promoted some change in the properties of the microspheres, which was ascribed to the strong interaction forces established between the alginate matrix and Cu2+ ions. The catalytic activity of Alg–Cu2+ was investigated towards the one-pot synthesis of 4-organylselanyl-1H-pyrazole derivatives via cyclocondensation reactions of diketones and hydrazines, followed by direct selenation reactions. In general lines, the starting reagents were efficiently converted via one-pot reactions to different derivatives in moderate to excellent yields. Moreover, the Alg–Cu2+ catalysts still maintained satisfactory catalytic activity even after five consecutive runs. These results indicate that the Alg–Cu2+ microspheres prepared in this study are a promising heterogeneous catalytic system for the synthesis of this class of substituted pyrazoles.

A peroxide-mediated protocol for the synthesis of 2-substituted benzothiazoles was developed, starting from bis(o-aminophenyl) disulfides and primary alcohols. Eleven differently 2-substituted benzothiazoles were prepared in moderate to excellent yields using di-tert-butyl peroxide (DTBP) as an oxidant.

A simple and efficient method for the synthesis of 4‑organoselanyl-1H-pyrazoles has been developed, taking place under metal- and halogen-free conditions. Electrophilic species of selenium were easily generated in situ by the reaction of diorganyl diselenides with Oxone® in ethanol as solvent in an open-flask at 70 °C. These electrophilic selenium species were employed in the selenylation/cyclization of α,β-alkynyl hydrazones, giving the title compounds in moderate to excellent yields. The final species of selenium obtained from the reaction of diphenyl diselenide with Oxone® were characterized by 77Se NMR spectroscopy and high-resolution mass spectrometry (HRMS).

The derivatization of chitosan (CS) is widely exploited to endow this polysaccharide with enhanced physicochemical and biological properties. Beyond the synthetic route, the nature of the compounds used to functionalize the CS-derivatives exerts a pivotal role in their final properties. Making use of a simple “click” reaction, we synthesized for the first time an organoselenium-CS derivative through a 1,2,3-triazole formation. The product (CS-TSe) was characterized in detail by FTIR, NMR (1H, 13C, and 77Se) and UV–Vis techniques, and SEM microscopy. The antioxidant activity of CS-TSe was examined by ABTS+ and DPPH (free radical-scavenging) assays. Experimentally, it was demonstrated that CS-TSe has superior antioxidant activity compared with raw CS and “free” organoselenium compound, suggesting a benign and synergistic effect due to the derivatization. In short, the antioxidant property of CS-TSe combined with the other attractive properties of CS and selenium could be useful in the formulation of advanced materials for biomedical and packaging applications.

This review presents the recent advances involving several applications of five-membered cyclic carbonates and derivatives. With more than 150 references, it covers the period from 2012 to 2020, with special emphasis on the use of five-membered cyclic carbonates as building blocks for organic synthesis and material elaboration. We demonstrate the application of cyclic carbonates in several important chemical transformations, such as decarboxylation, hydrogenation, and transesterification reactions, among others. The presence of cyclic carbonates in molecules with high biological potential is also displayed, together with the importance of these compounds in the preparation of materials such as urethanes, polyurethanes, and flame retardants.

Indazoles are fused azaheterocycles with wide applicability in the medical field. In the last decades, the pharmacology interest in this nucleus has increased due to a variety of compounds that show biological activities. Among them are antipyretic, analgesic, anti-inflammatory, antimicrobial, anti-HIV, anti-hypertensive, anti-tumour, anti-fungal and lately is used as an inhibitor of bacterial β-gyrase and a selective estrogen receptor. In addition, organochalcogen compounds have been widely explored due to their possible use as biologically active agents, or as key intermediates and catalysts in organic synthesis. Based on this and due to our continuous interest in the preparation of nitrogen-functionalized organochalcogen compounds, we describe herein our results on the synthesis of 3-(arylselanyl)- and (arylsulfenyl)-2H-indazoles by molecular iodine-catalyzed. Through the reaction of 2H-indazoles and a diverse range of diorganyl diselenides and diorganyl disulfates using catalytic amount of I2 (5 mol%) in DMSO (3.0 equiv.) as oxidant at 100 °C. This protocol proved to be simple, efficient and highly chalcogenated regioselectively at the C3 position to furnish a range of corresponding products selectively substituted 3-(organochalcogenyl)-2H-indazoles. A total of 15 examples were synthesized in good to excellent yields (36 to 98 % ). The products were obtained through a solvent and metal free methodology under mild conditions.

The contribution of oxidative stress has been described in numerous studies as one of the main pathways involved in the pathophysiology of anxiety and its comorbidities, such as chronic pain. Therefore, in this study, we investigated the anxiolytic-like, antiallodynic, and anti-hyperalgesic effects of 3,5-dimethyl-1-phenyl-4-(phenylselanyl)-1H-pyrazole (SePy) in response to acute restraint stress (ARS) in mice through the modulation of oxidative stress and neuroendocrine responses. Mice were restrained for 2 h followed by SePy (1 or 10 mg/kg, intragastrically) treatment. Behavioral, and biochemical tests were performed after further 30 min. The treatment with SePy reversed (i) the decreased time spent and the number of entries in the open arms of the elevated plus-maze apparatus, (ii) the decreased time spent in the central zone of the open field test and the increased number of grooming, (iii) the increased number of marbles buried, (iv) the increased response frequency of Von Frey Hair stimulation, and (v) the decreased latency time to nociceptive response in the hot plate test stress induced by ARS. Biochemically, SePy reversed ARS-induced increased levels of plasma corticosterone, and reversed the ARS-induced alterations in the levels of reactive species, lipid peroxidation, and superoxide dismutase and catalase activities in the prefrontal cortices and hippocampi of mice. Moreover, a molecular docking approach suggested that SePy may interact with the active site of the glucocorticoid receptor. Altogether, these results indicate that SePy attenuated anxiolytic-like behavior, hyperalgesia, and mechanical allodynia while modulating oxidative stress and neuroendocrine responses in stressed mice.

A general methodology to access valuable 3-arylquinoxalin-2(1H)-ones was developed, by the reaction of α-keto acids with ortho-phenylenediamines in the presence of ammonium niobium oxalate (ANO) as a catalyst. The reactions were conducted in only 10 min under ultrasonic irradiation as an alternative energy source, affording water as the only co-product. A total of twenty-three different 3-arylquinoxalin-2(1H)-ones were selectively obtained in good to excellent yields by this atom-efficient protocol. Additionally, 1H–15N HMBC experiments were used to reveal the regioisomerism of the obtained products.

Here, we report the general strategies by which NMR spectroscopy can be used to determine the enantiopurity and absolute configuration of chalcogen containing secondary alcohols, including the evaluation of the use of chiral solvating and chiral derivatizing agents. The BINOL/DMAP ternary complex demonstrated a simple and fast protocol for determining enantiopurity. The drug Naproxen afforded a stable, nonhygroscopic, and readily available chiral derivatizing agent (CDA) for NMR chiral discrimination of chalcogen containing secondary alcohols. The chiral recognition by CDA and chiral solvating agent (CSA) was assessed using 1 H, 77 Se-{1H}, and 125 Te-{1H} NMR spectroscopy. A simple model for the assignment of the absolute configuration from NMR data is presented.

A one-pot iodine-catalyzed multicomponent reaction has been developed for the selective preparation of 5-amino-4-(arylselanyl)-1H-pyrazoles from a diverse array of benzoylacetonitriles, arylhydrazines and diaryl diselenides. The reactions were conducted in MeCN as solvent at reflux temperature under air. The methodology presents a large functional group tolerance to electron-deficient, electron-rich, and bulky substituents and gave the expected products in good to excellent yields. The synthesized 1,3-diphenyl-4-(phenylselanyl)-1H-pyrazol-5-amine was submitted to an oxidative dehydrogenative coupling to produce a diazo compound confirmed by X-ray analysis.

Herein, we describe our results on the determination of the chemical profile of the essential oil (EO) of flowers from Tagetes minuta L. grown in Southern Brazil. The major component of the EO is (Z)-tagetone 1 (70.64% w/w). Thiotagetone 6, a semi-synthetic derivative, was prepared from 1 in 82% yield. Compounds 1 and 6 and the EO were evaluated for their antioxidant and antifungal activities in vitro. All the tested samples presented antioxidant effect in scavenging radical and in the lipid peroxidation assays. A good antifungal activity against Candida lipolityca, Candida parapsilosis, Trichosporon asahii and Sphaceloma ampelinum was observed. (Z)-Tagetone 1 inhibited the mycelia growth of S. ampelinum around 80% at 6 days. No acute toxicity (200 mg/kg) was observed in mice for the EO or the compounds 1 and 6. The lack of toxicity is an indicative for additional studies aiming their potential therapeutic use.

An efficient protocol to access 2-arylselanylbenzo[b]chalcogenophene derivatives through the Cu(I)-catalyzed annulation of vinyl selenides is described. The key vinyl selenides were easily prepared from properly functionalized 1,1-dibromostyrenes and the method allowed the synthesis of 2-arylselanylfurans, -thiophenes, and -selenophenes in moderate to excellent yields.

An efficient copper-catalyzed multicomponent reaction was developed for the synthesis of (arylselanyl)- or (arylsulfenyl)-alkyl-1,2,3-triazolo-1,3,6-triazonines. The products were obtained in moderate to excellent yields via the reaction of o-phenylenediamine, 2-azidobenzaldehyde and different arylchalcogenyl alkynes using catalytic copper iodide in 1,4-dioxane at 100 °C. The reactions tolerated a range of substituents on the arylchalcogenyl alkynes and proved to be an efficient methodology for the combinatorial synthesis of new selenium or sulfur-containing triazonine derivatives.

A convenient synthesis of 1-(2-organylchalcogenylethynyl)-2-butylselenanylbenzenes was established taking advantage of the selective reaction of 1-(2,2-dibromovinyl)-2-butylselenanylbenzenes with thiols or diorganyl diselenides. The new 1-(2-chalcogenylethynyl)-2-butylselenanylbenzenes were prepared in good yields and used as precursors of 2-organylchalcogenylbenzo[b]selenophenes via electrophilic cyclization using I2, Br2 or PhSeBr as electrophiles. Different classes of new 3-substituted- (3-iodo, 3-bromo, 3-phenylselenanyl) benzo[b]selenophenes were prepared in good yields. The synthetic application of the obtained products was demonstrated employing the benzo[b]selenophenes in Suzuki and Sonogashira cross-coupling reactions.

The use of sonochemistry is described in the organocatalytic enamine–azide [3 + 2] cycloaddition between 1,3-diketones and aryl azidophenyl selenides. These sonochemically promoted reactions were found to be amenable to a range of 1,3-diketones or aryl azidophenyl selenides, providing an efficient access to new ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones in good to excellent yields and short reaction times. In addition, this protocol was extended to β-keto esters, β-keto amides and α-cyano ketones. Selanyltriazoyl carboxylates, carboxamides and carbonitriles were synthesized in high yields at short times of reaction under very mild reaction conditions.

A significant number of important acyl-transfer reactions, such as direct acylation, ortho acylation, heteroatom acylation, and a diversity of cyclization reactions using the title compound as a key starting material, have been described in recent years. Just like a sleeping beauty, α-oxocarboxylic acids were awakened from a 17-year sleep to become important reagents in classical and new acylation reactions. The greener characteristic of the coproduct formed in reactions using α-keto acid (only CO2), together with its versatility as a building block in catalytic organic synthesis, accredit it as a candidate to green acylating agent, an alternative to acyl chloride, and other acyl-transfer reagents. This review presents the impressive breakthroughs achieved mainly in the past decade in the development of new catalytic reactions for the formation of C–C, C–N, and C–S bonds using α-keto acids.

We described herein the use of sonochemistry in the organocatalytic enamine-azide [3+2] cycloadditions of β-oxo-amides with a range of substituted aryl azides. These sonochemical promoted reactions were found to be amenable to a range of β-oxo amides or aryl azides, providing an efficient access to new N-aryl-1,2,3-triazoyl carboxamides in good to excellent yields and short times of reaction.

The use of renewable feedstocks, which may substitute those derived from petroleum, is currently a great challenge in the chemical and pharmaceutical industries. However, plant essential oils (EOs) that have been studied for their biological activities, such as antioxidant, antimicrobial, antifungal and antinociceptive are generally regarded as safe additives maintaining the microbiological stability of foods. EOs are a mixture of natural volatile compounds, that are predominantly formed during the secondary metabolism in plants and commonly concentrated in the leaves, bark or fruits of aromatic plants. They are complex mixtures composed mainly of terpenes (hydrocarbons or oxygenated compounds) and phenylpropanoids, which can be used as a source of raw materials for fine chemicals industry. In recent years, researchers and industries have been focusing on the major compounds of EOs in order to use them as solvents or as bio-based building blocks adding value to this material derived from biomass.

We present here the synthesis of novel (Z)-2-organylselanyl ketoximes by nucleophilic substitution reaction of E/Z mixtures of 2-bromo ketoximes with nucleophilic species of selenium, which were generated in situ by simple cleavage of diorganyl diselenides with NaBH4 using ethanol/THF as solvent. The new 2-organylselanyl ketoximes were synthesized in moderate to good yields and with selectivity for the (Z)-configuration. The synthesized (Z)-2-arylselanylacetophenone oximes were submitted to the Beckmann rearrangement, furnishing the corresponding N-aryl-2-(selanyl)acetamides. (Z)-1-Phenyl-2-(phenylselanyl) ketoxime has antifungal activity against Sphaceloma ampelinum and a good level of antioxidant activity in vitro in DPPH, ABTS, FRAP and lipid peroxidation assays.

We describe a selective method for synthesis of 4-chalcogenylmethyl-1,3-dioxolan-2-ones and 1,3-bis(organylchalcogenyl)propan-2-ols in a short reaction time through stoichiometric control. The use of 3-O-tosyl glycerol 1,2-carbonate and a set of aryl and alkyl diorganyl dichalcogenides afforded the desired products in good to excellent yields. We also describe a synthetic application to 4-chalcogenylmethyl-1,3-dioxolan-2-ones by base promoted the synthesis of 3-(arylchalcogenyl)propane-1,2-diols in excellent yields.

PEG-400 was used as a green and recyclable solvent in an efficient, simple and straightforward method for the synthesis of β-arylthio-α,β-unsaturated esters, ketone and aldehyde through the hydrothiolation of alkynes with arylthiols under base- and catalyst-free conditions. The reactions were performed under mild conditions and furnished selectively the respective ( Z )-β-arylthio-α,β-unsaturated compounds from alkynyl esters and ketone, while from alkynyl aldehyde, the ( E )-stereoisomer was obtained, in good yields and moderate reaction times. PEG-400 was reused in up 5 successive reactions without previous treatment, affording products in comparable yields.

Organochalcogen compounds (containing S, Se and Te) are interesting either for use as an intermediate in the synthesis of complex molecules or for the exploitation of their biological properties. The growing in the number of papers on the synthesis and application of organochalcogen compounds has been accompanied by a concern about how they are prepared. Here, we provide a comprehensive and updated review on recent synthetic methods available for their synthesis using alternative solvents or solvent-free conditions and non-classical energy sources (microwaves irradiation, sonochemistry and mechanochemistry). Organized in fourteen sections, this review brings the more than one hundred alternative methods described so far to access organic compounds containing selenium, tellurium and sulfur.

Bearing in mind that pain and major depressive disorder (MDD) often share biological pathways, this condition is classified as depression-pain syndrome. Mounting evidence suggests that oxidative stress is implicated in the pathophysiology of this syndrome. The development of effective pharmacological interventions for the depression-pain syndrome is of particular importance as clinical treatments for this comorbidity have shown limited efficacy. Therefore, the present study aimed to evaluate whether the 3,5-dimethyl-1-phenyl-4-(phenylselanyl)-1H-pyrazole (SePy) was able to reverse the depression-pain syndrome induced by intracerebroventricular (i.c.v) streptozotocin (STZ) in mice and the possible modulation of oxidative and nitrergic pathways in its effect. The treatment with SePy (1 and 10 mg/kg) administered intragastrically (i.g.) reversed the increased immobility time in the tail suspension test, decreased grooming time in the splash test, latency time to nociceptive response in the hot plate test, and the response frequency of Von Frey hair (VFH) stimulation induced by STZ (0.2 mg/4 μl/per mouse). Additionally, SePy (10 mg/kg, i.g.) reversed STZ-induced alterations in the levels of reactive oxygen species, nitric oxide, and lipid peroxidation and the superoxide dismutase and catalase activities in the prefrontal cortices (PFC) and hippocampi (HC) of mice. Treatment with SePy (10 mg/kg, i.g.) also reversed the STZ-induced increased expression of inducible nitric oxide synthase (iNOS) and glycogen synthase kinase 3 beta (GSK3β) in the PFC and HC. An additional molecular docking investigation found that SePy binds to the active site of iNOS and GSK3β. Altogether, these results indicate that the antidepressant-like effect of SePy is accompanied by decreased hyperalgesia and mechanical allodynia, which were associated with its antioxidant effect.

A one-pot iodine-catalyzed multicomponent reaction has been developed for the selective preparation of 5-amino-4-(arylselanyl)-1H-pyrazoles from a diverse array of benzoylacetonitriles, arylhydrazines and diaryl diselenides. The reactions were conducted in MeCN as solvent at reflux temperature under air. The methodology presents a large functional group tolerance to electron-deficient, electron-rich, and bulky substituents and gave the expected products in good to excellent yields. The synthesized 1,3-diphenyl-4-(phenylselanyl)-1H-pyrazol-5-amine was submitted to an oxidative dehydrogenative coupling to produce a diazo compound confirmed by X-ray analysis.

A green methodology to synthesize 2-organoselanyl-naphthalenes based on the reaction of alkynols with diaryl diselenides is described. The electrophilic species of selenium were generated in situ, by the oxidative cleavage of the Se–Se bond of diaryl diselenides by Oxone® using water as the solvent. The reactions proceeded efficiently under ultrasonic irradiation as an alternative energy source, using a range of alkynols and diorganyl diselenides as starting materials. Through this methodology, the corresponding 2-organoselanyl-naphthalenes were obtained in moderate to good yields (56–94%) and in short reaction times (0.25–2.3 h).

Herein we describe the reaction between the nucleophilic species of chalcogenium (sulfur, selenium and tellurium) and (R)- and (S)-solketal tosylates to prepare enantiomerically pure bis-1,3-dioxolanylmethyl chalcogenides and dichalcogenides in short reaction times and good yields. Furthermore, the new diselenide 4a was evaluated in the Michael reaction with acrylonitrile, giving (R)-3-[(2,3-dihydroxypropyl)selanyl]propanenitrile 6b after two steps.

We describe herein an efficient protocol to synthesize selanyl-substituted pyrazoles by cyclocondensation and copper-catalyzed direct CH bond selenation reactions. The products were obtained in moderate to excellent yields by the one-pot multicomponent reactions of hydrazines, 1,3-diketones and diorganyl diselenides, using catalytic amounts of copper bromide and bipyridine. These reactions tolerated a range of substituents in the starting materials and proved to be an efficient methodology for combinatorial synthesis of new selenium-containing pyrazoles with potential applications in biological studies.

An alternative green method was described for the synthesis of selanylesters by reactions of acyl chlorides with arylselenols, generated in situ by reaction of diaryl diselenides with hypophosphorous acid (H3PO2) using polyethylene glycol-400 (PEG-400) as the solvent. These reactions proceeded efficiently at room temperature under N2 using a range of acyl chlorides and diaryl diselenides, both containing electron-withdrawing and electron-donating groups, affording the corresponding selanylesters in moderate to excellent yields. Additionally, PEG-400 can be recovered and directly reused for further reactions.

Herein we describe the results on the synthesis and the evaluation of the antioxidant activity of several organochalcogen-containing chrysin derivatives (Se and Te). The semi-synthetic compounds were easily synthesized in good to excellent yields by the reaction of 7-(2-bromoethoxy)-chrysin with nucleophilic organoselenium and organotellurium species. The antioxidant properties of Se- and Te-containing chrysin derivatives were evaluated by three different in vitro assays, the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activities and ferric ion reducing antioxidant power (FRAP). Compounds 4i (which contains the butyltellurium moiety) and 4j (which contains a 4-phenyltellurium moiety) exhibited higher activities than chrysin and the selenium analogues, with compound 4i being the most potent antioxidant.

Background: The main constituents of Cymbopogonnardus (L) Rendle and C. citratus (DC) Stapfessential oils are (R)-citronellal and citral, respectively. Organochalcogen compounds can boost the biological activities of natural products. Methods: Several chalcogen-containing nitrones derived from (R)-citronellal and citral were prepared and evaluated for their antimicrobial and antioxidant activities. The antimicrobial activity was evaluated by the disc diffusion test and the antioxidant properties were evaluated in vitro by DPPH (1,1-diphenyl-2-picryl-hydrazyl), ABTS (2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), and FRAP (ferric ion reducing antioxidant power) assays. Results: In the antimicrobial assay, (E)-N,3,7-trimethyl-3-(phenylthio)oct-6-en-1-imine oxide 5c exhibited halos between 21.5 mm (Escherichia coli O157:H7) and 26.0 mm (Listeria monocytogenes), while (E)-N,3,7-trimethyloct-6-en-1-imine oxide 5d presented halos between 22.5 mm (E. coli O157:H7) and 31.0 mm (L. monocytogenes). (E)-N,3,7-Trimethyl-2-(phenylthio)oct-6-en-1-imine oxide 5a showed the lowest minimal inhibitory concentration (MIC) value against Bacillus cereus (0.48 mM), and 5c was the most potent bactericide, with a minimal bactericidal concentration (MBC) of 0.52 mM for E. coli O157:H7. In the antioxidant assays, 5c, 5d, and 10 ((E)-3,7-dimethyl-2-(phenylselanyl)oct-6-enal oxime) were the most actives in the DPPH, ABTS, and FRAP assays, respectively. Conclusions: The presence of a phenylthio group in the nitrone increases its antimicrobial activity against Gram-positive and Gram-negative foodborne pathogens in the disk diffusion test and the antioxidant activity in vitro.