Thioacetal

Thiocetale are chemical compounds which are derived from aldehydes and, instead of the carbonyl group of ( a) two thiol groups (- SR1 and SR2 ) or (b ) each have a thiol group (- SR1) and an alkoxy group or aryloxy group ( - OR2 ) contain, are attached to the same carbon atom. You are gem- arranged sulfur analogs of di-ethers.

Originally, ( a hydrogen atom ), and the analogous compounds formed from ketones, the so-called thioketals, thioacetals formed from differences between the aldehydes. Nowadays also thioketals are usually regarded as a subclass of thioacetals.

In the formation of thioacetals from aldehydes or ketones and thiols are formed as intermediates, the Hemi or Monothiohalbacetale ( R'2C (SR ) (OH) ), which can only be isolated in some cases.

Synthesis

Dithioacetals formed during the reaction of aldehydes (eg acetaldehyde ) and mono-or divalent thiols (for example, 1,3- propane dithiol ) with elimination of water. Usually, this condensation reaction is conducted with acid catalysis.

Acetals as protecting groups

In synthetic chemistry dithioacetals are often used as protective groups for carbonyl groups of aldehydes or ketones.

In the Corey -Seebach reaction Dithioacetals serve as intermediates for the synthesis of unsymmetrical ketones from aldehydes.

Related compounds

S, N- acetals

When the carbonyl group of an aldehyde or a ketone is reacted with a 1,2- aminothiol dehydration, produces a S, N- acetal. Thiazolidines and 3- thiazoline are examples of heterocyclic S, N- acetals.