Compounds of formula I or II ##STR1## wherein R.sup.1 and R.sup.2 are hydrogen, alkyl, cyclohexyl, phenyl, benzyl or tolyl, or are a --CH.sub.2 --CHR.sup.3 --CH.sub.2 --S--CO--R.sup.4 radical, R.sup.3 is hydrogen or methyl, R.sup.4 is alkyl, cyclohexyl, phenyl, benzyl or tolyl, X is alkylene, --S--, --SO--, --SO.sub.2 -- or substituted alkylene, in which R.sup.5 and R.sup.6 are hydrogen or alkyl, and n is an integer from 1 to 10, can be used as latent hardeners for epoxy resins.The compositions containing epoxy resins and these hardeners are particularly suitable for use as single component adhesive formulations. The cured products have good hot water resistance.