There is disclosed a water-soluble, asymmetrical oxalic acid diarylamide of general formula ##STR1## wherein the substituents R.sub.1 are each independently of the other unsubstituted or hydroxy- or alkoxy-substituted C.sub.1 -C.sub.5 alkyl, unsubstituted or C.sub.1 -C.sub.5 alkyl-substituted benzyl, R.sub.2 is hydrogen, halogen, C.sub.1 -C.sub.12 alkyl or phenyl-C.sub.1 -C.sub.5 alkyl, R.sub.3 is hydrogen, halogen, C.sub.1 -C.sub.12 alkyl, phenyl-C.sub.1 -C.sub.5 alkyl or C.sub.1 -C.sub.5 alkoxy, A is a direct bond or a divalent radical of formula --O--Q--, wherein Q is unsubstituted or hydroxy-substituted C.sub.1 -C.sub.6 alkylene, M is hydrogen or alkali metal, and r is 2, 1 or 0. The novel water-soluble compound having fiber affinity is suitable for the photochemical and thermal stabilisation of polyamide fiber materials and the dyeings produced thereon.
Oxamides useful as dye intermediates have the formula ##STR1## where R.sup.1 and R.sup.2 are independently of each other hydrogen, C.sub.1 -C.sub.4 -alkyl or phenyl, X is hydroxyl, nitro or a radical of the formula --NR.sup.3 R.sup.4, where R.sup.3 is hydrogen or C.sub.1 -C.sub.4 -alkanoyl and R.sup.4 is hydrogen, C.sub.1 -C.sub.4 -alkyl or phenyl, Z is C.sub.2 -C.sub.8 -alkylene, substituted or unsubstituted phenylene or substituted or unsubstituted naphthylene, or X--Z and R.sup.1 are, together with the nitrogen atom joining them together, the radical of the formula ##STR2## where R.sup.3 is as defined above, L is a bridge member and Y is vinyl or a radical of the formula --C.sub.2 H.sub.4 --A, where A is hydroxyl or a group which is detachable under alkaline reaction conditions.
