Synthesis of 5-Seleno-Substituted Spirocyclopenta[b]pyridine-2,5-dien-4-ones and Benzo[h]quinolines via Radical Cyclization of Arylethynylpyridines.

A practical strategy for obtaining novel 5-seleno-substituted spirocyclopenta[b]pyridines-2,5-dien-4-ones and benzo[h]quinolines via radical cyclization is reported. The synthetic protocol explores the reaction between arylethynylpyridines and diorganyl diselenides in acetonitrile as solvent and Oxone® as oxidant at 82 °C. This easy-to-handle, eco-friendly metal-free approach was carried out under an open atmosphere, affording functionalized organoselenium compounds in good to excellent yields.

Synthesis of Selenium-Decorated -Oxide Isoquinolines: Arylseleninic Acids in Selenocyclization Reactions.

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--oxides through the selenocyclization of -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 -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.

Iodine/Oxone® oxidative system for the synthesis of selenylindoles bearing a benzenesulfonamide moiety as carbonic anhydrase I, II, IX, and XII inhibitors.

A wide range of 3-selenylindoles were synthesized an eco-friendly approach that uses Oxone® as the oxidant in the presence of a catalytic amount of iodine. This mild and economical protocol showed broad functional group tolerance and operational simplicity. A series of novel selenylindoles bearing a benzenesulfonamide moiety were also synthesized and evaluated as carbonic anhydrase inhibitors of the human (h) isoforms hCa I, II, IX, and XII, which are involved in pathologies such as glaucoma and cancer.