New Experimental Conditions for Diels-Alder and Friedel-Crafts Alquilation Reactions with Thiophene: A New Selenocyanate with Potent Activity against Cancer

Organoselenium Compounds in Medicinal Chemistry

The chemical and biological interest in this element and the molecules bearing selenium has been exponentially growing over the years. Selenium, formerly designated as a toxin, becomes a vital trace element for life that appears as selenocysteine and its dimeric form, selenocystine, in the active sites of selenoproteins, which catalyze a wide variety of reactions, including the detoxification of reactive oxygen species and modulation of redox activities. From the point of view of drug developments, organoselenium drugs are isosteres of sulfur-containing and oxygen-containing drugs with the advantage that the presence of the selenium atom confers antioxidant properties and high lipophilicity, which would increase cell membrane permeation leading to better oral bioavailability. This statement is the paramount relevance considering the big number of clinically employed compounds bearing sulfur or oxygen atoms in their structures including nucleosides and carbohydrates. Thus, in this article we have focused on the relevant features of the application of selenium in medicinal chemistry. With the increasing interest in selenium chemistry, we have attempted to highlight the most significant published data on this subject, mainly concentrating the analysis on the last years. In consequence, the recent advances of relevant pharmacological organoselenium compounds are discussed.

ADME Study, Molecular Docking, Elucidating the Selectivities and the Mechanism of [4 + 2] Cycloaddition Reaction Between (E)-N ((dimethylamino)methylene)benzothioamide and (S)-3-acryloyl-4-phenyloxazolidin-2-one

The molecular electron density theory (MEDT) was employed to examine the [4 + 2] cycloaddition reaction between (E)-N-((dimethylamino)methylene)benzothioamide (1) and (S)-3-acryloyl-4-phenyloxazolidin-2-one (2) at the B3LYP/6-311++G(d,p) design level. Parr functions and energy studies clearly show that this reaction is regio- and stereoselective, in perfect agreement with experimental results. By evaluating the chemical mechanism in terms of bond evolution theory (BET) and electron localization function (ELF), which divulges a variety of variations in the electron density along the reaction path, a single-step mechanism with highly asynchronous transition states structures was revealed. Additionally, we conducted a docking study on compounds P1, P2, P3, and P4 in the SARS-CoV-2 main protease (6LU7) in comparison to Nirmatrelvir. Our findings provide confirmation that product P4 may serve as a potent antiviral drug.

Potential of sulfur-selenium isosteric replacement as a strategy for the development of new anti-chagasic drugs

Current treatment for Chagas disease is based on only two drugs: benznidazole and nifurtimox. Compounds containing sulfur (S) in their structure have shown promising results in vitro and in vivo against Trypanosoma cruzi, the parasite causing Chagas disease. Notably, some reports show that the isosteric replacement of S by selenium (Se) could be an interesting strategy for the development of new compounds for the treatment of Chagas disease. To date, the activity against T. cruzi of three Se- containing groups has been compared with their S counterparts: selenosemicarbazones, selenoquinones, and selenocyanates. More studies are needed to confirm the positive results of Se compounds. Therefore, we have investigated S compounds described in the literature tested against T. cruzi. We focused on those tested in vivo that allowed isosteric replacement to propose their Se counterparts as promising compounds for the future development of new drugs against Chagas disease.