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. An important class are S-glycosides, such as octylthioglucoside, which are formed by a reaction between thiols and sugars. Other examples include 2-hydroxytetrahydrothiophene and the anti-HIV drug Lamivudine. Another class of isolable hemithioacetals are derived from carbonyl groups that form stable hydrates. For example, thiols react with hexafluoroacetone trihydrate to give hemithioacetals, which can be isolated.