A thioether (similar to sulfide) is a functional group in organic chemistry that has the structure R¹-S-R² as shown on right. Like many other sulfur-containing compounds, volatile thioethers characteristically have foul odors.^[1] Image File history File links No higher resolution available. ... Formally, sulfide is the dianion, S2−, which exists in strongly alkaline aqueous solutions formed from H2S or alkali metal salts such as Li2S, Na2S, and K2S. Sulfide is exceptionally basic and, with a pKa > 14, it does not exist in appreciable concentrations even in highly alkaline water. ... Organic chemistry is a specific discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting of primarily carbon and hydrogen, which may contain any number of other elements, including nitrogen, oxygen, halogens as well... Look up volatile in Wiktionary, the free dictionary. ...

A thioether is similar to an ether except that it contains a sulfur atom in place of the oxygen. Because oxygen and sulfur belong to the chalcogens group in the periodic table, the chemical properties of ethers and thioethers share some commonalities. This functional group is important in biology, most notably in the amino acid methionine and the cofactor biotin. Ether is the general name for a class of chemical compounds which contain an ether group — an oxygen atom connected to two (substituted) alkyl groups. ... The chalcogens (with the ch pronounced with a hard c as in chemistry) are the name for the periodic table group 16 (old-style: VIB or VIA) in the periodic table. ... Monument to the periodic table, in front of the Faculty of Chemical and Food Technology of the Slovak University of Technology in Bratislava, Slovakia. ... Phenylalanine is one of the standard amino acids. ... Methionine (Met, M. C5H11NO2S) is an essential nonpolar amino acid, and a lipotropic. ... A cofactor is the following: In mathematics a cofactor is the minor of an element of a square matrix. ... Vitamin H redirects here. ...

Preparation

• Thioethers are typically prepared by the alkylation of thiols:

R-Br + HS-R' → R-S-R' + HBr

Such reactions are accelerated in the presence of base, which converts the thiol into the more nucleophilic thiolate. Alkylation is the transfer of an alkyl group from one molecule to another. ... Sulphydryl // In organic chemistry, a thiol is a compound that contains the functional group composed of a sulfur atom and a hydrogen atom (-SH). ...

• An alternative method of synthesis includes the addition of a thiol to an alkene, typically catalysed by free radicals:

R-CH=CH₂ + HS-R' → R-CH₂-CH₂-S-R'

• Thioethers can also be prepared via the Pummerer rearrangement.

The chemical structure of ethylene, the simplest alkene. ... In chemistry free radicals are uncharged atomic or molecular species with unpaired electrons or an otherwise open shell configuration. ... The Pummerer rearrangement is a chemical reaction whereby an alkyl sulfoxide rearranges to an α-acyloxythioether in the presence of acetic anhydride. ...

Reactions

• While ethers are generally stable, thioethers (R-S-R) are easily oxidized to the sulfoxides (R-S(=O)-R), which can themselves be further oxidized to sulfones (R-S(=O)₂-R). For example, dimethyl sulfide can be oxidized as follows:

S(CH₃)₂ + O → OS(CH₃)₂

OS(CH₃)₂ + O → O₂S(CH₃)₂

Typical oxidants include peroxides. A sulfoxide is a chemical compound containing a sulfinyl functional group with a sulfur oxygen double bond attached to two carbon atoms. ... A sulfone is a chemical compound containing a sulfonyl functional group attached to two carbon atoms. ... Dimethyl sulfide causes that distinctive smell from your St. ... Look up O, o in Wiktionary, the free dictionary. ... Dimethyl sulfoxide The United States DoDs Defense Modeling and Simulation Office This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Look up O, o in Wiktionary, the free dictionary. ... Flash point 143 °C R/S statement R: S: 24/25 RTECS number PB2785000 Related compounds Related sulfones  ? Related compounds DMSO dimethyl sulfide Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references Methylsulfonylmethane (MSM, or dimethylsulfone) is... Peroxide has three distinct meanings: // Main article: hydrogen peroxide In common usage, peroxide is an aqueous solution of hydrogen peroxide (HOOH or H2O2) sold for use as a disinfectant or mild bleach. ...

• The sulfur-sulfur bond in disulfides is susceptible to cleavage by nucleophiles, and reaction with a carbon nucleophile produces a thioether:

R₃C^- + R¹S-SR² → R₃CSR¹ + R²S^-

• Trialkysulfonium salts react with nucleophiles with a dialkyl sulfide as a leaving group:

Nu^- + R₃S⁺ → Nu-R + R-S-R

This reaction is exploited in biological systems as a means of transferring an alkyl group. For example, S-adenosylmethionine acts as a methylating agent in biological S_N2 reactions. In chemistry, a disulfide is an ion formed by sulfur atoms. ... An alkyl is a univalent radical containing only carbon and hydrogen atoms arranged in a chain. ... This article does not cite its references or sources. ... Methylation is a term used in the chemical sciences to denote the attachment or substitution of a methyl group on various substrates. ... The SN2 reaction is a type of nucleophilic substitution, where a nucleophile attacks an electrophilic center and bonds to it, expelling another group called a leaving group. ...

• Ethers can be alkylated at oxygen only with difficulty to give highly reactive trialkyloxonium salts. In contrast, thioethers are readily alkylated to give stable sulfonium salts, such as trimethylsulfonium:

S(CH₃)₂ + CH₃I → [S(CH₃)₃]⁺I^-

STRATCO Contactorâ„¢ Reactor Sulfuric Acid Alkylation Alkylation is the transfer of an alkyl group from one molecule to another. ... A sulfonium ion, also known as sulfonium compound, is a positively charged sulfur atom carrying three alkyl groups as substituents (S+R3). ...

Thiophenes

The heterocyclic compound thiophene is formally a thioether. Because of the aromatic character of this heterocycle, the nonbonding electrons on sulfur, normally responsible for the nucleophilicity so characteristic of thioethers, are delocalized into the π-system. Consequently thiophene exhibits few properties expected for a thioether - thiophene is non-nucleophilic at sulfur and, in fact, is sweet-smelling. Upon hydrogenation, thiophene gives tetrahydrothiophene, C₄H₈S, which indeed does behave as a typical thioether. Pyridine a simple heterocyclic compound Heterocyclic compounds are organic compounds which contain a ring structure containing atoms in addition to carbon, such as sulfur, oxygen or nitrogen, as part of the ring. ... Thiophene is an aromatic heterocyclic compound consisting of four carbon atoms and one sulfur atom in a five-membered ring. ... In chemistry, an aromatic molecule is one in which electrons are free to cycle around circular arrangements of atoms, which are alternately singly and doubly bonded to one another. ... Heterocycles are organic chemical structures containing non-carbon elements. ... In chemistry, a nucleophile (literally nucleus lover) is a reagent which is attracted to centres of positive charge. ... In chemistry delocalized electrons are electrons in a molecule that are not associated with a single atom or to a covalent bond. ...

References