Hemithioacetal

In organic chemistry, hemithioacetals (or thiohemiacetals) are organosulfur compounds with the general formula R−CH(−OH)−SR’.

They typically are intermediates in the formation of dithioacetals (R−CH(S−R’)2): Hemithioacetals ordinarily readily dissociate into thiol and aldehyde, however, some have been isolated.

In general, these isolable hemithioacetals are cyclic, which disfavors dissociation, and can often be further stabilized by the presence of acid.

[2] An important class are S-glycosides, such as octylthioglucoside, which are formed by a reaction between thiols and sugars.

[4] Another class of isolable hemithioacetals are derived from carbonyl groups that form stable hydrates.