thumb|150px|right|The structure of a sulfone

thumb|[[Methylsulfonylmethane|Dimethyl sulfone, an example of a sulfone]]

In organic chemistry, a sulfone is a organosulfur 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.

Synthesis and reactions

By oxidation of thioethers and sulfoxides

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.

For example, 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 derived from sulfonyl halides and sulfonic acid anhydrides. Lewis acid catalysts such as and are required.

Sulfones have been prepared through sulfinate anion alkylation. S<sub>N</sub>2 displacement of a wide variety of halides gives exclusively sulfones...<chem display=block>ArSO2Na + Ar'Cl -> Ar(Ar')SO2 + NaCl</chem> ...but some highly active alkylating agents give a sulfinate ester instead. The ester may or may not rearrange to the sulfone via dissociation-association. but allyl, propargyl, and benzyl sulfinates can rearrange when heated neat.

Reactions

A relatively inert functional group, sulfones are typically less oxidizing and only 4&nbsp;bel more acidic than sulfoxides. but leave about 9&nbsp;bel more slowly than chloride.

Sulfones are strongly electron-withdrawing, and

vinyl sulfones are electrophilic Michael acceptors.

The behavior of the α carbon depends on context. Non-nucleophilic bases deprotonate, giving an enolate-like carbanion.

Sulfones can also undergo reductive desulfonylation. Precursors to such polymers are the sulfones bisphenol S and 4,4′-dichlorodiphenyl sulfone.

Pharmacology

thumb|222px|[[Dapsone, an antibiotic used for the treatment of leprosy.]]

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.

See also

  • Organosulfur chemistry
  • Sulfonanilide
  • Sulfoxide
  • Sulfonic acid (–OH substituent)

References