A process for the production of polyurethanes where (a) polyisocyanate, (b) polymeric compounds having groups reactive toward isocyanates, selected from the group of the polyether polyols, polyester polyols and mixtures thereof with functionality from 2 to 8 and with number-average molar mass from 400 to 15 000 g/mol, (c) catalysts, (d) a CH-acidic compound of the general formula: where H- is hydrogen, -X- is mutually independently oxygen or a -NH-group, preferably -O-, -A- is mutually independently a linear or branched-chain aliphatic or aromatic hydrocarbon moiety having from 2 to 20 carbon atoms, -O- is oxygen, S is an aliphatic, cycloaliphatic or aromatic, linear or branched-chain hydrocarbon moiety which can have substitution, -C - is a carbonyl moiety, -CH 2 - is a methylene moiety, R 1 is mutually independently NO 2 or an electron-withdrawing moiety of the general formula - C -R 2, and R 2 is mutually independently a moiety selected from the group consisting of H, -NH 2, -NH-R 3 -NR 4 R 5, OR 6 or R 7, where R 3, R 4, R 5, R 6 and R 7 independently are selected from the group consisting of aliphatic, araliphatic or aromatic hydrocarbons, which may have substitution, and l and n are mutually independently integers from 0 to 200, m is integers from 0 to 7 and o is integers from 1 to 8 and p is integers from 0 to 7, with the proviso that the sum of m, o and p is not greater than 8, and optionally (e) blowing agent, (f) chain extender and or crosslinking agent, and (g) auxiliaries and/or additives are mixed to give a reaction mixture, and the reaction mixture is allowed to complete a reaction to give the polyurethane. (a) polyisocyanate, (b) polymeric compounds having groups reactive toward isocyanates, selected from the group of the polyether polyols, polyester polyols and mixtures thereof with functionality from 2 to 8 and with number-average molar mass from 400 to 15 000 g/mol, (c) catalysts, (d) a CH-acidic compound of the general formula: where H- is hydrogen, -X- is mutually independently oxygen or a -NH-group, preferably -O-, -A- is mutually independently a linear or branched-chain aliphatic or aromatic hydrocarbon moiety having from 2 to 20 carbon atoms, -O- is oxygen, S is an aliphatic, cycloaliphatic or aromatic, linear or branched-chain hydrocarbon moiety which can have substitution, -C - is a carbonyl moiety, -CH 2 - is a methylene moiety, R 1 is mutually independently NO 2 or an electron-withdrawing moiety of the general formula - C -R 2, and R 2 is mutually independently a moiety selected from the group consisting of H, -NH 2, -NH-R 3 -NR 4 R 5, OR 6 or R 7, where R 3, R 4, R 5, R 6 and R 7 independently are selected from the group consisting of aliphatic, araliphatic or aromatic hydrocarbons, which may have substitution, and l and n are mutually independently integers from 0 to 200, m is integers from 0 to 7 and o is integers from 1 to 8 and p is integers from 0 to 7, with the proviso that the sum of m, o and p is not greater than 8, and optionally H- is hydrogen, -X- is mutually independently oxygen or a -NH-group, preferably -O-, -A- is mutually independently a linear or branched-chain aliphatic or aromatic hydrocarbon moiety having from 2 to 20 carbon atoms, -O- is oxygen, S is an aliphatic, cycloaliphatic or aromatic, linear or branched-chain hydrocarbon moiety which can have substitution, -C - is a carbonyl moiety, -CH 2 - is a methylene moiety, R 1 is mutually independently NO 2 or an electron-withdrawing moiety of the general formula - C -R 2, and R 2 is mutually independently a moiety selected from the group consisting of H, -NH 2, -NH-R 3 -NR 4 R 5, OR 6 or R 7, where R 3, R 4, R 5, R 6 and R 7 independently are selected from the group consisting of aliphatic, araliphatic or aromatic hydrocarbons, which may have substitution, and l and n are mutually independently integers from 0 to 200, m is integers from 0 to 7 and o is integers from 1 to 8 and p is integers from 0 to 7, with the proviso that the sum of m, o and p is not greater than 8, and optionally (e) blowing agent, (f) chain extender and or crosslinking agent, and (g) auxiliaries and/or additives are mixed to give a reaction mixture, and the reaction mixture is allowed to complete a reaction to give the polyurethane.