Compounds of the general formula I Z—CH2—NY2−nHn  (I) where n is 0 or 1, Z is a straight-chain or branched polyalkyl radical having a number average molecular weight of from about 150 to 40,000, and Y is a radical of the formula IIa or IIb  where the radicals R, R1 and R2 independently of one another, are each hydrogen, an unsubstituted or substituted alkyl, alkenyl or alkynyl radical or an unsubstituted or substituted cycloalkyl, aryl or arylalkyl radical, which may carry one or more heteroatoms, and A is an alkyleneimine radical; or, if n is 0, one of the radicals Y may be a polyoxyalkylene radical, and processes for their preparation and fuel and lubricant compositions, and mixtures of additives, which contain the novel compounds.