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Despite the high potential as feedstockfor the production of fuelsand chemicals, the industrial cultivation of microalgae still exhibitsmany issues. Yield in microalgae cultivation systems is limited bythe solar energy that can be harvested. The availability of reliablemodels representing key phenomena affecting algae growth may helpdesigning and optimizing effective production systems at an industriallevel. In this work the complex influence of different light regimeson seawater alga Nannochloropsis salinagrowth isrepresented by first principles models. Experimental data such as in vivofluorescence measurements are employed to developthe model. The proposed model allows description of all growth curvesand fluorescence data in a reliable way. The model structure is assessedand modified in order to guarantee the model identifiability and theestimation of its parametric set in a robust and reliable way. [ABSTRACT FROM AUTHOR]

Herein, we describe the use of benzeneseleninic acid derivatives (BSA) as a bench-stable and easy to handle selenium reagent to access 4-(selanyl)isoquinoline- N -oxides through the selenocyclization of o -alkynyl benzaldehyde oximes. The reaction is conducted in refluxing methanol, allowing the thermal generation of electrophilic selenium species in situ. By this new protocol, a library of 19 selenium-decorated N -oxide isoquinolines was accessed in up to 96% yield with an outstanding substrate tolerance and the feasibility to scale it up 10 times (from 0.25 to 2.5 mmol).

We describe here for the first time the synthesis of 2-(chalcogenyl)-3 H -benzo[ f ]chromenes and the new 3-(phenylselanyl)-2 H -chromenes by the radical or electrophilic cyclization of propargylic aryl ethers in the presence of diorganyl diselenides or ditellurides using Oxone as a green oxidant and acetonitrile as solvent in a sealed tube at 100 °C. In this study, thirty-one chalcogenylchromenes with a broad substrate scope were prepared in moderate to excellent yields (50-98%), including compounds derived from natural products.

We report herein an alternative method for the synthesis of seleno-dibenzocycloheptenones and seleno-spiro[5.5]trienones through the radical cyclization of biaryl ynones in the presence of diorganyl diselenides, using Oxone as a green oxidizing agent. The reactions were conducted using acetonitrile as the solvent in a sealed tube at 100 °C. The protocol is operationally simple and scalable, exhibits high regioselectivity, and allows the synthesis of 24 dibenzocycloheptenones/spiro[5.5]trienones in yields of up to 99%, 17 of which are unpublished compounds. Additionally, synthetic transformations of the prepared compounds, such as oxidation and reduction reactions, are demonstrated.

A new method was developed for the synthesis of 4-chalcogenyl-1 H -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 5 H -selenopheno[3,2- c ]isochromen-5-ones. Additionally, for the first time, the 4-chalcogenyl-1 H -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.

Despite major advances, not all patients achieve rheumatoid arthritis (RA) remission, thus highlighting a pressing need for new therapeutic treatments. Given this scenario, this study sought to evaluate Se-[(2,2-dimethyl-1,3-dioxolan-4-yl)methyl] 4-chlorobenzoselenolate (Se-DMC) potential on a complete Freund's adjuvant (CFA)-induced unilateral arthritis model. The effects of Se-DMC (5 mg/kg; oral dose) and meloxicam (5 mg/kg; oral dose), both administered to animals daily for 14 days, on paw edema, mechanical sensitivity, neurobehavioral deficits (anxiogenic- and depressive-like behaviors), Na + /K + -ATPase activity, oxidative stress, and inflammation were evaluated in male Swiss mice exposed to CFA (intraplantar injection of 0.1 mL; 10 mg/mL). Se-DMC reduced the paw withdrawal threshold and CFA-induced paw edema. Histopathological results revealed the antiedematogenic potential of the compound, which was evidenced by lower quantities of dilated lymphatic vessels compared with the CFA group. Se-DMC reduced mRNA relative expression levels of tumor necrosis factor-α (TNF-α) and nuclear factor-κB (NF-κB) in the hippocampus and paw of CFA mice. The CFA-induced anxiogenic- and depressive-like behaviors were reversed by Se-DMC to the control levels in the elevated plus-maze and tail suspension tests. Se-DMC reduced the paw reactive species levels and restored the superoxide dismutase (hippocampus and paw) and Na + /K + -ATPase (hippocampus) activities previously increased by CFA. Moreover, CFA administration inhibited serum creatinine kinase activity, albeit the Se-DMC effects did not appear to involve the modulation of this enzyme and were equal to or greater than meloxicam. Se-DMC attenuates CFA-induced inflammatory response, nociception, and neurobehavioral deficits in mice.

We report a protocol for the synthesis of 3-organyl-4-(organylchalcogenyl)isoquinoline-2-oxides via electrophilic cyclization between alkynylbenzaldoximes and diorganyl dichalcogenides promoted by Oxone. A total of 21 3-organyl-4-(organylchalcogenyl)isoquinoline-2-oxides were selectively obtained in yields of up 93% under an ultrasound irradiation condition in short reaction times (10-70 min). Additionally, the synthetic usefulness of the 3-phenyl-4-(phenylselanyl)isoquinoline-2-oxide was demonstrated in the annulation reaction with 1-(2-bromophenyl)-3-phenylprop-2-yn-1-one and in the deoxygenation reaction with phenylboronic acid.

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 CO 2 ), 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 describe herein a new approach to prepare unprecedented bioactive indolizine motifs decorated with organosulfur and organoselenium groups. A total of 12 1-sulfanylindolizines and 2 1-selanylindolizines were prepared in excellent yields by an intramolecular annulation of easily prepared chalcogen-containing pyridinium salts. The reaction is fast (1 h at 70 °C or 5 min under sonication) and transition-metal-free, using glycerol as a green solvent.

A simple method for the direct mono- and bis-organylselenylation of N-substituted pyrroles through a multicomponent reaction promoted by ultrasonic radiation was described. These sonochemical promoted reactions were performed between different primary amines, 2,5-hexanedione and dialkyl, diheteroaryl, or diaryl diselenides, using catalytic amounts of copper iodide. Depending on the amount of copper iodide and diorganyl diselenide used in the reactions, mono- or bis-organylselenylation products were efficiently synthesized in high yields.

Organocatalytic enamine-azide [3 + 2] cycloadditions between β-keto sulfones and aryl azides can be performed at room temperature in good to excellent yields of products in the presence of catalytic amounts of pyrrolidine (5 mol %). The proposed organocatalytic methodology was found to be applicable to β-keto arylsulfones containing a range of substituents. A wide variety of aryl azides also work. Basically, this constitutes a remarkably efficient protocol for the synthesis of novel 1,2,3-triazole compounds.