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Potassium permanganate absorbed on copper(II) sulfate pentahydrate has been found to be an efficient, inexpensive, and green oxidation agent for the synthesis of “symmetrical” thiosulfonateS-esters by oxidation of the corresponding symmetrical disulfides. The oxidation reactions were carried out under solvent-free reaction conditions within 15 min under the influence of microwave irradiation, as well as (for comparison) supported by conventional heating, to afford yields of the thiosulfonateS-esters in the range of 60–83%. The oxidation reaction appears to proceed (at least partly) via an intermediate symmetricalvic-disulfoxide. [ABSTRACT FROM PUBLISHER]

The solvent-free potassium permanganate (KMnO4)-promoted oxidation of alcohols into the corresponding carbonyl derivatives has been examined in detail with respect to the importance of supporting materials and supporting irradiation. Secondary alcohols are oxidized very efficiently to the corresponding ketones at ambient temperature by KMnO4 absorbed on a fourfold molar amount of copper(II) sulfate pentahydrate. The reaction is accelerated considerably by ultrasonic irradiation and drastically by microwave irradiation. Under the latter conditions, also hydroquinone can be converted 100% into p-benzoquinone within 4.5 min. Benzylic alcohols are oxidized most efficiently to the corresponding benzaldehydes under heterogeneous reaction conditions. [ABSTRACT FROM AUTHOR]