New One-Pot Synthesis of Catechol Thioethers Based on H2S and Unsaturated Hydrocarbons

New one-pot synthesis of catechol thioethers based on the reaction between H2S, 3,5-di-tert-butyl-o-benzoquinone and unsaturated hydrocarbons was developed. This synthetic approach allows to produce target compounds in the media of alkenes or alkynes via an activation of H2S by 3,5-di-tert-butyl-o-benzoquinone at room temperature. The method consists in sequential thiolation of an unsaturated hydrocarbon and a sterically hindered o-benzoquinone. The reaction makes it possible to use hydrogen sulfide as a source of the sulfur atom in the synthesis of biologically active organosulfur compounds. Antioxidant activity of synthesized thioethers in CUPRAC-test, induced oxidation of DNA or glutathione was determined. The proposed synthetic way is more effective than the synthesis of catechol thioethers via Michael addition of thiols because the formation of disulfide by-products is reduced. In this study the application of available and cheap reagents such as hydrogen sulfide, alkenes, or alkynes to prepare sterically hindered catechols with thioether group was established.