Bereiding en reacties van thiolen

Thiols are a class of sulfur-containing organic compounds with an –SH functional group.

They are usually prepared from alkyl halides via an S_N2 reaction with a sulfur nucleophile such as a hydrosulfide anion.

For example, 1-bromobutane reacts with sodium hydrosulfide to give 1-butanethiol.

Here, the hydrosulfide anion exerts a strong nucleophilic attack on the carbon bearing the halide group, thus displacing the halide ion in an S_N2 manner and forming the thiol.

However, this synthesis method does not work well because the product thiol can undergo a second S_N2 reaction with the alkyl halide, generating sulfide as a by-product.

This limitation can be overcome by using a thiourea as the nucleophile. Thiourea displaces the halide ion on the alkyl halide to form an alkyl isothiourea salt intermediate.

The salt then undergoes hydrolysis with an aqueous base and yields thiol as a product.

Thiols readily undergo oxidation to form disulfides, sulfinic, and sulfonic acids owing to the multiple oxidation states of the sulfur atom.

The oxidation of thiols to sulfonic acid via sulfinic acid requires strong oxidizing agents such as hydrogen peroxide or potassium permanganate.

Oxidation of thio