Sulfoxide

Sulfoxides are in chemistry, a class of compounds with organically bound sulfur and oxygen of the general structure R1 -S ( = O) -R2, while R1 and R2 are organic radicals. The sulfoxides are on the oxidation state between the sulfides R1 -S -R2 and R1- sulfones S ( = O) 2 - R2.

Chirality of sulfoxides

When the radicals R1 and R2 are different, the corresponding sulfoxide is chiral, that is there are two enantiomeric ( mirror image ) forms of this sulfoxide. Other than suggested by the viewing of the structural formula, all valence electrons of the sulfur atom do not form part of covalent bonds.

The electrostatic repulsion between the nonbonding electron pair and the bonding electrons leads to sulfoxides are not built planar but pyramidal. Hence the chirality of asymmetric sulfoxides (R1 ≠ R2).

Production

For the synthesis of sulfoxides the corresponding thioethers ( sulfides ) are oxidized. There are also procedures for preparation of enantiomerically pure sulfoxides.

Occurrence

As an ingredient of various Allium natural sulfoxide Cycloalliin is known.

Use

Sulfoxides are semi-volatile and polar compounds, the simplest representative of this class of compounds is used as the solvent dimethyl sulfoxide. Some sulfoxides ( esomeprazole, omeprazole, lansoprazole ( Takeda ), rabeprazole ( Eisai ) and pantoprazole ) have as a drug from the group of proton pump inhibitors practical importance in the treatment of gastric and duodenal ulcers and in reflux oesophagitis.

Dimethyl sulphoxide is used as the oxidant in the Kornblum oxidation.

Reactivity

The oxidation of sulfoxides with hydrogen peroxide or potassium permanganate, provides sulfones.