Additives for lubricant compositions

A lubricant composition which comprises

• (a) a lubricant, and
• (b) 0.05 to 5% by weight, based on component (a), of at least one compound of formula I ##STR22## wherein R.sup.1 and R.sup.2 are each independently C.sub.1 -C.sub.24 -alkyl, C.sub.1 -C.sub.24 alkyl which is interrupted by one or more identical or different members selected from --O--, --S-- and/or ##STR23## and/or which contains one or more oxo and/or thiono groups;
• or C.sub.3 -C.sub.24 alkenyl, C.sub.2 -C.sub.4 hydroxyalkyl, C.sub.5 -C.sub.8 cycloalkyl, phenyl or phenyl which is substituted by one or two C.sub.1 -C.sub.12 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.2 -C.sub.24 alkoxycarbonyl and/or nitro groups;
• or naphthyl, C.sub.7 -C.sub.10 aralkyl, furan-2-ylmethyl or tetrahydrofuran-2-ylmethyl, or R.sup.1 and R.sup.2, together with the nitrogen atom to which they are attached, form a 5- or 6-membered mononuclear aliphatic heterocyclic ring which, in addition to the N atom, may contain one or two additional N, O and/or S atoms as ring members and/or one or two oxo and/or thiono groups as substituents, or form an indolinyl, 1,2,3,4-tetrahydroquinolinyl or 1,2,3,4-tetrahydroisoquinolinyl radical which radicals are unsubstituted or substituted by 1 to 3 methyl groups, and R.sup.3 is hydrogen or C.sub.1 -C.sub.8 alkyl.