Silicon-Assisted Synthesis and Functionalization of Sulfurated and Selenated Compounds

Application of Bulky NHC-Rhodium Complexes in Efficient S-Si and S-S Bond Forming Reactions

The efficient and straightforward syntheses of silylthioethers and disulfides are presented. The synthetic methodologies are based on new rhodium complexes containing bulky N-heterocyclic carbene (NHC) ligands that turned out to be efficient catalysts in thiol and thiol-silane coupling reactions. These green protocols, which use easily accessible reagents, allow obtaining compounds containing S-Si and S-S bonds in solvent-free conditions. Additionally, preliminary tests on coupling of mono- and octahydro-substituted spherosilicates with selected thiols have proved to be very promising and showed that these catalytic systems can be used for the synthesis of a novel class of functionalized silsesquioxane derivatives.

Syntesis of thio- and seleno-acetamides bearing benzenesulfonamide as potent inhibitors of human carbonic anhydrase II and XII

A novel series of thio- and seleno-acetamides bearing benzenesulfonamide were synthetized and tested as human carbonic anhydrase inhibitors. These compounds were tested for the inhibition of four human (h) isoforms, hCA I, II, IX, and XII, involved in pathologies such as glaucoma (CA II and XII) or cancer (CA IX/XII). Several derivatives showed potent inhibition activity in low nanomolar range such as 3a, 4a, 7a and 8a. Furthermore, based on the tail approach we explain the interesting and selective inhibition profile of compound such as 5a and 9a, which were more selective for hCA I, 9b which was selective for hCA II, 3f selective for hCA IX and finally, 3e and 4b selective for hCA XII, over the other three isoforms. They are interesting leads for the development of more effective and isoform-selective inhibitors.

Towards New Catalytic Antioxidants: A Simple and Mild Synthesis of Selenenylsulfides

A new methodology for the synthesis of small molecules containing the S-Se bond is reported. Aryl- and alkyl-selenols react smoothly with N-thiophthalimides to afford the corresponding selenenylsulfides through a clean SN2 path occurring at the sulfur atom. The reaction proceeds under very mild conditions in DMF in absence of catalysts for most of the substrates. The scope of the reaction was found to be broad, allowing a wide series of selenols and N-thiophtalimides to be efficiently employed in this procedure. Owing to the instability of the S-Se bond, selenenylsulfides exhibited a remarkable tendency to disproportionate to the corresponding symmetric diselenides and disulfides. Preliminary evaluation of the catalytic antioxidant properties of novel selenenylsulfides showed their behaviour as GPx mimics.

Mild and selective silicon-mediated access to enantioenriched 1,2-mercaptoamines and β-amino arylchalcogenides

Metal-free ring opening reactions of activated and unactivated aziridines with different silyl chalcogenides are described.

Ring opening reactions of heterocycles with selenium and tellurium nucleophiles

An overview of the preparation and synthetic potentialities of functionalized organoselenium and organotellurium compounds is presented.

Synthesis of different thio-scaffolds bearing sulfonamide with subnanomolar carbonic anhydrase II and IX inhibitory properties and X-ray investigations for their inhibitory mechanism

Several new molecules with different thio-scaffolds were designed, synthesised, and evaluated biologically as inhibitors of Carbonic Anhydrases (CAIs). The structure-activity relationship analysis identified thioether derivatives, here reported, as a potent and selective CAIs against hCA II and hCA IX. High resolution X-ray structure of inhibitor bound hCA II revealed extensive interactions with the hydrophobic pocket of active site and provided molecular insight into the binding properties of these new inhibitors.

Synthesis of Novel Selenides Bearing Benzenesulfonamide Moieties as Carbonic Anhydrase I, II, IV, VII, and IX Inhibitors

A series of novel selenides bearing benzenesulfonamide moieties was synthesized and investigated for the inhibition of five human (h) isoforms of zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), hCA I, II, IV, VII, and IX. These enzymes are involved in a variety of diseases, including glaucoma, retinitis pigmentosa, epilepsy, arthritis, and tumors. The investigated compounds showed potent inhibitory action against hCA II, VII, and IX, in the low nanomolar range, thus making them of interest for the development of isoform-selective inhibitors and as candidates for biomedical applications.