Green Approach for the Synthesis of Chalcogenyl- 2,3-dihydrobenzofuran Derivatives Through Allyl-phenols/ Naphthols and Their Potential as MAO-B Inhibitors.

This work presents the design, synthesis, and MAO-B inhibitor activity of a series of chalcogenyl-2,3-dihydrobenzofurans derivatives. Using solvent- and metal-free methodology, a series of chalcogen-containing dihydrobenzofurans 7-9 was obtained with yields ranging from 40% to 99%, using an I2 /DMSO catalytic system. All compounds were fully structurally characterized using 1 H and 13 C NMR analysis, and the unprecedented compounds were additionally analyzed using high-resolution mass spectrometry (HRMS). In addition, the mechanistic proposal that iodide is the most likely species to act in the transfer of protons along the reaction path was studied through theoretical calculations. Finally, the compounds 7b-e, 8a-e, and 9a showed great promise as inhibitors against MAO-B activity.

Formation of Dimethyl Carbonate from CO2 and Methanol Catalyzed by Me2SnO: A Density Functional Theory Approach.

The conversion of CO2 into dimethyl carbonate (DMC) is an environmental and industrial appealing topic because it contributes to reduce the emissions of CO2 and to increase its use as raw material. In the present study we employed the CAM-B3LYP/def2-SVP DFT approach to evaluate the thermodynamic and kinetic parameters for the catalytic conversion of CO2 and methanol into DMC. Starting with the activation of four methanol molecules by the [Me2SnO]2 dimer, we computed all the stationary points along the pathway to convert CO2 and methanol into the DMC. The capture of two CO2 molecules is promoted by an alkoxitin intermediate, in an exothermic process, with low activation energy. Formation of a first DMC occurs after an intramolecular rerrangement involving a tetrahedral intermediate. The formation of a second DMC may occur either in a process similar to the first one or by dimerization of the hemicarbonate formed after releasing the first DMC. In this pathway, the [Me2(OH)SnO(OMe)SnMe2]2 complex is formed. This complex is less reactive than [Me2Sn(OMe)2]2 but still conserves the catalytic activity. Identification of this mechanism suggests that the catalytic action of Me2SnO can be improved by modulating the formation of the final [Me2(OH)SnO(OMe)SnMe2]2 complex.