Synthesis of enantiomerically pure glycerol derivatives containing an organochalcogen unit: In vitro and in vivo antioxidant activity

Recent Progress in Synthesis and Application of Chiral Organoselenium Compounds

Chiral organoselenium compounds have shown an important role as intermediates in many areas, such as drug discovery, organic catalysis, and nanomaterials. A lot of different methods have been developed to synthesize chiral compounds which contain selenium, because they have interesting properties and can be used in real life. Over the last few decades, a lot of progress has been made in synthesizing chiral organoselenium compounds. This work gives an overview of the progress made in creating new ways to synthesize chiral organoselenium compounds by categorizing them into groups based on the reactions they undergo. In addition, the use of chiral organoselenium compounds is also discussed.

Recent Advances in the Synthesis and Antioxidant Activity of Low Molecular Mass Organoselenium Molecules

Selenium is an essential trace element in living organisms, and is present in selenoenzymes with antioxidant activity, like glutathione peroxidase (GPx) and thioredoxin reductase (TrxR). The search for small selenium-containing molecules that mimic selenoenzymes is a strong field of research in organic and medicinal chemistry. In this review, we review the synthesis and bioassays of new and known organoselenium compounds with antioxidant activity, covering the last five years. A detailed description of the synthetic procedures and the performed in vitro and in vivo bioassays is presented, highlighting the most active compounds in each series.

Transition-metal-free C-S, C-Se, and C-Te Bond Formation from Organoboron Compounds

The present review describes the successful application of organoboron compounds in transition-metal-free C-S, C-Se, and C-Te bond formations. We presented studies regarding these C-Chalcogen bond formations using organoboron reagents, such as boronic acids, boronic esters, borate anions, and several sources of chalcogen atoms/moieties. Moreover, a broad range of transition-metal-free approaches to synthesize sulfides, selenides, and tellurides were described using conventional heating methods, which are sometimes green since they use green solvents, safe reagents, among others. Furthermore, protocols using alternative energy sources, including ultrasound, microwave irradiation, photocatalysis, and electrolytic processes, were also shown to be suitable. These protocols were applied to prepare a broad scope of functionalized chalcogenides with high molecular diversity. These studies and their proposed mechanisms were also reported herein in addition to the reuse of reaction promoters.

Diselenides and Selenocyanates as Versatile Precursors for the Synthesis of Pharmaceutically Relevant Compounds

Organoselenium chemistry has undergone extensive development during the past decades, mostly due to the unique chemical properties of organoselenium compounds that have been widely explored in a number of synthetic transformations, as well as due to the interesting biological properties of these compounds. Diselenides and selenocyanates constitute the promising classes of organoselenium compounds that possess interesting biological effects and that can be used in the preparation of other selenium compounds. The combination of diselenide and selenocyanate moieties with other biologically relevant molecules (such as heterocycles, steroids, etc.) is a way for the development of compounds with promising pharmaceutical potential. Therefore, the aim of this review is to highlight the recent achievements in the use of diselenides or selenocyanates as precursors for the synthesis of pharmaceutically relevant compounds, preferentially compounds with antitumor and antimicrobial activities.

Green Production of Glycerol Ketals with a Clay-Based Heterogeneous Acid Catalyst

Glycerol remains a bottleneck for the biodiesel industry as well as an opportunity from the biorefinery perspective, having a notable reactivity as a platform chemical. In particular, glycerol ketals can be envisaged as oxygenates for fuel formulation. In this study, we have focused on the green synthesis of glycerol ketals by reacting glycerol with acyclic (acetone, butanone) and cyclic (cyclohexanone) ketones in the presence of an acid activated clay Tunisian AC in homogeneous systems under quasi-solventless conditions. These reactions were followed by on-line Fourier Transform Infrared Spectroscopy (FTIR) (namely, ReactIR 10). Firstly, the contacting time was selected studying the activity, stability and chemical characteristics of a set of catalysts. The 1-h activated clay AC was further characterized by X-Ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electronic Microscopy with Energy Dispersive Spectroscopy (SEM/EDS). Finally, the effect of the main operational variables (catalyst concentration, reagents molar ratio, time and temperature) were checked and we reflected on adequate second-order kinetic models with partial first-order deactivation.

Ultrasound-promoted synthesis of 2-organoselanyl-naphthalenes using Oxone® in aqueous medium as an oxidizing agent

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).