Sulfone

A sulfone is a chemical compound containing a sulfonyl functional group attached to two carbon atoms. The central hexavalent sulfur atom is double-bonded to each of two oxygen atoms and has a single bond to each of two carbon atoms, usually in two separate hydrocarbon substituents. A sulfone is a chemical compound containing a sulfonyl functional group attached to two carbon atoms. The central hexavalent sulfur atom is double-bonded to each of two oxygen atoms and has a single bond to each of two carbon atoms, usually in two separate hydrocarbon substituents. Sulfones are typically prepared by organic oxidation of thioethers, often referred to as sulfides. Sulfoxides are intermediates in this route. For example, dimethyl sulfide oxidizes to dimethyl sulfoxide and then to dimethyl sulfone. Sulfur dioxide is a convenient and widely used source of the sulfonyl functional group. Specifically, Sulfur dioxide participates in cycloaddition reactions with dienes.The industrially useful solvent sulfolane is prepared by addition of sulfur dioxide to buta-1,3-diene followed by hydrogenation of the resulting sulfolene. Sulfones are prepared under conditions used for Friedel–Crafts reactions using sources of RSO2+ derived from sulfonyl halides and sulfonic acid anhydrides. Lewis acid catalysts such as AlCl3 and FeCl3 are required. Sulfones have been prepared by nucleophilic displacement of halides by sulfinates: Sulfone is a relatively inert functional group, being weakly basic (compared to sulfoxides). They are non-oxidizing. In the Ramberg–Bäcklund reaction and the Julia olefination, sulfones are converted to alkenes by the elimination of sulfur dioxide. Sulfolane is used to extract valuable aromatic compounds from petroleum. Some polymers containing sulfone groups are useful engineering plastics. They exhibit high strength and resistance to oxidation, corrosion, high temperatures, and creep under stress. For example, some are valuable as replacements for copper in domestic hot water plumbing. Precursors to such polymers are the sulfones bisphenol S and 4,4′-dichlorodiphenyl sulfone. Examples of sulfones in pharmacology include dapsone, a drug formerly used as an antibiotic to treat leprosy, dermatitis herpetiformis, tuberculosis, or pneumocystis pneumonia (PCP). Several of its derivatives, such as promin, have similarly been studied or actually been applied in medicine, but in general sulfones are of far less prominence in pharmacology than for example the sulfonamides.