Abstract: The present invention provides 1,6-naphthyridine derivatives of formula ##STR1## wherein R.sup.1 is an unsubstituted or substituted aromatic or heteroaromatic ring or an unsubstituted or substituted condensed aromatic or heterocyclic ring system, R.sup.2 is a straight-chained or branched alkyl radical containing up to 4 carbon atoms, a benzyl radical or a straight-chained or branched, substituted or unsubstituted aminoalkyl radical containing up to 8 carbon atoms, R.sup.3 is a hydrogen atom, a straight-chained or branched alkyl radical or an alkoxycarbonyl radical, in each case containing up to 4 carbon atoms, R.sup.4 is a straight-chained or branched hydrocarbon radical containing up to 21 carbon atoms, which can also contain oxygen, sulphur, nitrogen or halogen atoms and is optionally substituted by carbocyclic or heterocyclic ring systems, or is an amino, cyano, formyl, halogenomethyl or dihalomethyl radical and R.sup.