Compounds of the formula I in which R 1 denotes Ar, COHet or Het, R 2 denotes H, Ar 1, NHHet or Het, R 3 denotes H or A', R 4 denotes H, A, Ar 1, Het, Hal, NHAr 1 or CN, Ar denotes phenyl or naphthyl which is unsubstituted or mono- or disubstituted by Hal, A, Cyc, [C(R 3) 2] p OA, [C(R 3) 2] p OH, CN, NHCOHet 1, NHCOA, NHCO[C(R 3) 2] p Cyc, CONH[C(R 3) 2] p Cyc, [C(R 3) 2] p N(R 3) 2, [C(R 3) 2] p Het 1, NR 3 SO 2 A, SO 2 N(R 3) 2, S n A, COHet 1, O[C(R 3) 2] m N(R 3) 2 and/or O[C(R 3) 2] p Het 1, Ar 1 denotes phenyl which is unsubstituted or mono- or disubstituted by Hal, A, phenyl, CONH 2, [C(R 3) 2] p OR 3, [C(R 3) 2] p N(R 3) 2, [C(R 3) 2] p CN, [C(R 3) 2] p Het 1 and/or O[C(R 3) 2] p Het 1, Het denotes furyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidyl, pyridazinyl, pyrazinyl, indolyl, isoindolyl, benzimidazolyl, indazolyl, quinolyl, 1,3-benzodioxolyl, benzothiophenyl, benzofuranyl, imidazopyridyl, dihydroindolyl, 2,3-dihydro-benzo[1,4]dioxinyl or furo[3,2-b]pyridyl which is unsubstituted or mono-, di- or trisubstituted by Hal, A, [C(R 3) 2] p OR 3, [C(R 3) 2] p -N(R 3) 2, [C(R 3) 2) p Het 1, NO 2, CN, [C(R 6) 2] p COOR 3, CON(R 3) 2, NR 3 COA, NR 3 SO 2 A, SO 2 N(R 3) 2, S n A, COHet 1, O[C(R 3) 2] m N(R 3) 2, O[C(R 3) 2] p Het 1 and/or =O, Het 1 denotes dihydropyrrolyl, pyrrolidinyl, azetidinyl, oxetanyl, tetra-hydroimidazolyl, dihydropyrazolyl, tetrahydropyrazolyl, tetrahydrofuranyl, dihydropyridyl, tetrahydropyridyl, piperidinyl, morpholinyl, hexahydropyridazinyl, hexahydropyrimidinyl, [1,3]dioxolanyl, tetrahydropyranyl, pyridyl or piperazinyl, which is unsubstituted or mono- or disubstituted by Hal, CN, OH, OA, COOA, CONH 2, S n A, S n Ar, COA, A and/or =O, A denotes unbranched or branched alkyl with 1-10 C-atoms, wherein one or two non-adjacent CH- and/or CH 2 -groups may be replaced by N-, O- and/or S-atoms and wherein 1-7 H-atoms may be replaced by F or Cl, Cyc denotes cyclic alkyl with 3-7 C-atoms, which is unsubstituted or monosubstituted by [C(R 3) 2] p OH or CN, A' denotes unbranched or branched alkyl with 1, 2, 3 or 4 C-atoms, Hal denotes F, Cl, Br or I, n denotes 0, 1 or 2, m denotes 1, 2 or 3, p denotes 0, 1, 2, 3 or 4, and pharmaceutically acceptable solvates, salts, tautomers and stereoisomers thereof, including mixtures thereof in all ratios. R 1 denotes Ar, COHet or Het, R 2 denotes H, Ar 1, NHHet or Het, R 3 denotes H or A', R 4 denotes H, A, Ar 1, Het, Hal, NHAr 1 or CN, Ar denotes phenyl or naphthyl which is unsubstituted or mono- or disubstituted by Hal, A, Cyc, [C(R 3) 2] p OA, [C(R 3) 2] p OH, CN, NHCOHet 1, NHCOA, NHCO[C(R 3) 2] p Cyc, CONH[C(R 3) 2] p Cyc, [C(R 3) 2] p N(R 3) 2, [C(R 3) 2] p Het 1, NR 3 SO 2 A, SO 2 N(R 3) 2, S n A, COHet 1, O[C(R 3) 2] m N(R 3) 2 and/or O[C(R 3) 2] p Het 1, Ar 1 denotes phenyl which is unsubstituted or mono- or disubstituted by Hal, A, phenyl, CONH 2, [C(R 3) 2] p OR 3, [C(R 3) 2] p N(R 3) 2, [C(R 3) 2] p CN, [C(R 3) 2] p Het 1 and/or O[C(R 3) 2] p Het 1, Het denotes furyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidyl, pyridazinyl, pyrazinyl, indolyl, isoindolyl, benzimidazolyl, indazolyl, quinolyl, 1,3-benzodioxolyl, benzothiophenyl, benzofuranyl, imidazopyridyl, dihydroindolyl, 2,3-dihydro-benzo[1,4]dioxinyl or furo[3,2-b]pyridyl which is unsubstituted or mono-, di- or trisubstituted by Hal, A, [C(R 3) 2] p OR 3, [C(R 3) 2] p -N(R 3) 2, [C(R 3) 2) p Het 1, NO 2, CN, [C(R 6) 2] p COOR 3, CON(R 3) 2, NR 3 COA, NR 3 SO 2 A, SO 2 N(R 3) 2, S n A, COHet 1, O[C(R 3) 2] m N(R 3) 2, O[C(R 3) 2] p Het 1 and/or =O, Het 1 denotes dihydropyrrolyl, pyrrolidinyl, azetidinyl, oxetanyl, tetra-hydroimidazolyl, dihydropyrazolyl, tetrahydropyrazolyl, tetrahydrofuranyl, dihydropyridyl, tetrahydropyridyl, piperidinyl, morpholinyl, hexahydropyridazinyl, hexahydropyrimidinyl, [1,3]dioxolanyl, tetrahydropyranyl, pyridyl or piperazinyl, which is unsubstituted or mono- or disubstituted by Hal, CN, OH, OA, COOA, CONH 2, S n A, S n Ar, COA, A and/or =O, A denotes unbranched or branched alkyl with 1-10 C-atoms, wherein one or two non-adjacent CH- and/or CH 2 -groups may be replaced by N-, O- and/or S-atoms and wherein 1-7 H-atoms may be replaced by F or Cl, Cyc denotes cyclic alkyl with 3-7 C-atoms, which is unsubstituted or monosubstituted by [C(R 3) 2] p OH or CN, A' denotes unbranched or branched alkyl with 1, 2, 3 or 4 C-atoms, Hal denotes F, Cl, Br or I, n denotes 0, 1 or 2, m denotes 1, 2 or 3, p denotes 0, 1, 2, 3 or 4,