Thioether

Thioethers are organic sulfides, ie in chemistry, a hydrocarbon group having the general structure R1 -S -R2, where R1 and R2 are organic radicals. They are the sulfur analogs of ethers. Those derived from alkanes thioethers are also known as dialkyl sulfides. Compounds having multiple sulfur atoms (n> 1 ) in series, R1 -Sn - R2, di -, tri-, etc. mentioned sulfides, such as disulfides, R1 -S-S -R2. In symmetric thioethers (R1 -S -R1) the two organic radicals are identical, in unsymmetrical thioethers (R1 -S -R2 ), they are different. In dialkylsulfides two organic radicals are alkyl groups, aryl groups, and in diaryl sulfides are in Alkylarylsulfiden R1 is an alkyl group and R 2 is an aryl group.

Representation

Thioethers can be thiolates with (alkaline ) by reaction of alkyl halides, synthesized by reduction of sulfoxides or sulfones or by double alkylation of sulfur dichloride. By Asinger reaction, heterocyclic sulfides with a sulfur atom and a reactive C = N double bond can be represented in the ring.

Properties

Chemical Properties

Thioether form salt-like addition compounds with halogens, alkyl halides or metal salts. Their oxidation products are sulfoxides R 1 -SO -R2, and sulfones, R1- SO2 - R2.

Physical Properties

Volatile thioether often have a very unpleasant odor. The simplest representative of this class of compound is the volatile dimethyl sulfide (bp 37 ° C). They are usually insoluble in water.

Occurrence

The proteinogenic amino acid methionine is a thioether. The dimer of the amino acid cysteine ​​, cystine, contains a disulfide bridge. These bridges are important for the formation of secondary and tertiary structures of proteins, for example in the keratin.

Dimethyl sulfide is formed, for example, in the decomposition of sulfur-containing proteins and is a contributor to odor occurring. The sickening stench of the Stinkhorn, Phallus impudicus is mainly caused by dimethyl di - and trisulfide. The latter two are also important for smell and taste of different truffles, especially the white truffle, Tuber Magnatum. The sensory main component bis ( methylthio ) methane, CH 2 ( SCH 3 ) 2, may also be referred to as thioether, but is rather to be construed as thioacetal of formaldehyde.

The chemical warfare agent mustard gas, bis (2 -chloroethyl ) sulfide, is also a thioether.