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.

Benzeneseleninic acid (BSA) derivatives were used as an alternative, but extremely useful, source of Se(II)-based electrophiles, generated in situ by thermal decomposition, to construct C–Se bonds, accessing 3-selanylimidazopyridines after reaction with 2-substituted imidazopyridines. A total of thirty-four derivatives were synthesized in 50–94% yield, seventeen of which were so far unprecedented. A simple and efficient protocol is described, just delivering H₂O and diaryl diselenide as by-products. Diaryl diselenides can be easily recovered during the purification process and converted again to BSA for a new reaction.

Here, we describe a magnetic resonance spectroscopy characterization of selenium cyanide compounds, Se(CN)₂, Se₂(CN)₂ and Se₃(CN)₂. Selenim-77 and carbon-13 nuclides were used to provide data of these species at room temperature. This is the first structural characterization performed using NMR for Se₃(CN)₂, while only low-temperature analyses have been conducted so far for Se(CN)₂ and Se₂(CN)₂. Based on these limitations, a characterization study was deemed mandatory, especially from a synthetic chemistry point of view. In addition to these analyses, we carried out a purity assessment for Se₃(CN)₂ according to the melting point parameter along with a solubility evaluation.

In the present work, a mild protocol was developed to construct 2‐aryl‐3‐(arylselanyl)imidazo[1,2‐ a ]pyridines, under blue light irradiation, employing benzeneseleninic acid derivatives as a Se(II) source. The experimental design approach (design of experiment, DoE) was used to establish the best reaction conditions, which delivered fourteen derivatives in moderate to good yields (23%–75%), after reacting for 24–48 h. Furthermore, the developed method proved to be efficient when increasing the reaction scale (2.5 mmol), which provided the desired product in 70% yield (0.61 g) after 24 h of reaction, demonstrating the applicability of this method on a preparative scale. The present approach does not require the use of metals, strong oxidants, or heating, in addition to producing only H ₂ O and diaryl diselenide as byproducts, which can be recovered and reused.