In Organic chemistry, a thiol (before named mercaptan of the Latin mercurius captans “which collects mercury”) is a Composé organics comprising a grouping thiol - HS (Groupement sulfhydryle) attached to a carbon atom. They are in general compounds with strong Odeur.

Thiols are similar to the alcohol S, with the oxygen of the Groupement hydroxyl - OH replaced by a sulfur atom, this is why they are also called “thiolalcool”. It will be noted that oxygen and sulfur have similar chemical properties because they belong to the same group (even column) of the periodic Tableau. Thiols form Thioéther S, thioacetal S and Thioester S, in which one or more atoms of Oxygène are replaced by an atom of Soufre.

Many thiols are colorless liquids having an odor close to that of the garlic. The odor is rather strong and pushing back: thiols strongly bind to proteins of the skin. This property is partly responsible for the persistent odor produced by a Moufette when it projects its nauseous liquid. One adds éthylmercaptan (éthanethiol) to the Natural gas (which is normally without odor) in order to detect the escapes.

When a grouping thiol is substituted for a hydrogen atom in a Alcane, there are two manners of naming resulting thiol:

• the suffix - thiol can be added in the name of alkane. For example, CHSH will be the méthanethiol . The 2-furylméthanethiol , CHOS is a molecule responsible for the flavor of the coffee whose stimulative action is due to cafeine;
• the word mercaptan can also replace the word alcohol in the name of the compound. For example, knowing that CHOH is the carbinol, CHSH will be the méthylmercaptan.

When grouping HS is not the principal grouping, the prefix used is sulfanyl- . In the past, the prefix used was mercapto- , and this use is still largely widespread.

Thiols react with the ions mercury according to:

$\backslash \; mathrm\; \{Hg\}\; ^\; \{2+\}\; +\; 2\; \backslash \; mathrm\; \{R-SH\}\; \backslash \; \backslash \; rightarrow\; \backslash \; \backslash \; mathrm\; \{Hg\; (SR)\}\_2\; +\; 2\; \backslash \; mathrm\; \{H\}\; ^+$

This property their was worth the name of “mercaptan”, i.e.: “which collects mercury”.

Some examples of thiols:

• Méthanethiol (méthylmercaptan) - CHSH
• Éthanethiol (éthylmercaptan) - CHSH
• Coenzyme has
• Lipoamide
• Glutathion
• Cystéine (NH2) - (CH-CH2-SH) - (COOH)

* When two cysteins approach one the other, their grouping thiol can condense following a reaction of moderate oxidation:

* 2R-SH + ↔ R-S-S-R + H2O

*cystéine oxidant cystine water

* It results the formation from it from a bridge disulfide. This reaction can take place between cysteins belonging to different polypeptides (reaction interchaîne) or to the same polypeptide (reaction intrachaîne) and intervenes in the tertiary structure of protein concerned.

• Acétylcystéine
• …

Sources

• Jacques Angeneau, chemistry , encyclopedic dictionary
• Albert Lehninger, Biochemistry

Random links:

Canton of Cléguérec | All that the sky allows | Lenient | Combeauté | Jacopo Vignali