2-(piperidin-4-yl)-4,5-dihydro-2H-pyridazin-3-one derivatives as PDE4 inhibitors

1. A compound of formula 1

in which

R1 is 1-4C-alkyl and

R2 is 1-4C-alkyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is 1-4C-alkoxy or 1-4C-alkoxy which is completely or predominantly substituted by fluorine,

R5 is 1-8C-alkoxy, 3-7C-cycloalkoxy, 3-7C-cycloalkylmethoxy, or 1-4C-alkoxy which is completely or predominantly substituted by fluorine,

R9 is —C(O)R10, —S(O) 2 —R14, —(CH 2 ) n —C(O)—R18 or —C(O)—(CH 2 ) m —R21,

R10 is 1-4C-alkyl, —N(R11)R12, phenyl or phenyl substituted by R13,

R11 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

R12 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

or R11 and R12 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrohidinyl-, 1-piperidinyl-, 1-piperazinyl, 1-(1-4C-alkyl)-piperazin-4-yl-, 1-hexahydroazepinyl-, 4-morphohinyl, 4-thiomorphohinyl-, thiomorphohin-1-oxide-4-yl- or thiomorpholin-1,1-dioxide-4-yl-ring,

R13 is hydroxyl, halogen, nitro, cyano, hydroxycarbonyl, 1-4C-alkyl, trifluoromethyl, 1-4C-alkoxy, 1-4C-alkoxy which is completely or predominantly substituted by fluorine, 1-4C-alkoxycarbonyl, amino, mono- or di-1-4C-alkylamino, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkylcarbonyl, 1-4C-alkylcarbonylamino or 1-4C-alkylcarbonyloxy,

R14 is 1-4C-alkyl, —N(R15)R16, phenyl or phenyl substituted by R17,

R15 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

R16 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

or R15 and R16 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1-piperazinyl, 1-(1-4C-alkyl)-piperazin-4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl, 4-thiomorpholinyl-, thiomorpholin-1-oxide-4-yl- or thiomorpholin-1,1-dioxide-4-yl-ring,

R17 is hydroxyl, halogen, nitro, cyano, carboxyl, 1-4C-alkyl, trifluoromethyl, 1-4C-alkoxy, 1-4C-alkoxy which is completely or predominantly substituted by fluorine, 1-4C-alkoxycarbonyl, amino, mono- or di-1-4C-alkylamino, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkylcarbonyl, 1-4C-alkylcarbonylamino or 1-4C-alkylcarbonyloxy,

R18 is —N(R19)R20,

R19 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

R20 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

or R19 and R20 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1-piperazinyl, 1-(1-4C-alkyl)-piperazin-4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl, 4-thiomorpholinyl-, thiomorpholin-1-oxide-4-yl- or thiomorpholin-1,1-dioxide-4-yl-ring,

R21 is —N(R22)R23,

R22 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

R23 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

or R22 and R23 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1-piperazinyl, 1-(1-4C-alkyl)-piperazin-4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl, 4-thiomorpholinyl-, thiomorpholin-1-oxide-4-yl-, thiomorpholin-1,1-dioxide-4-yl-, pyrrolidin-2,5-dione-1-yl-, morpholin-3,5-dione-4-yl-, piperidin-2,6-dione-1-yl, 4,4-dimethyl-piperidin-2,6-dione-1-yl or a 1-methyl-imidazolidine -2,4-dione-3-yl-ring or a isoindol-1,3-dione-2-yl-ring-system,

n is an integer from 1 to 4,

m is an integer from 1 to 4,

or a salt thereof.

2. A compound of formula 1 according to claim 1 , in which

R1 is 1-4C-alkyl,

R2 is 1-4C-alkyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is 1-2C-alkoxy or 1-2C-alkoxy which is completely or predominantly substituted by fluorine,

R5 is 1-2C-alkoxy or 1-2C-alkoxy which is completely or predominantly substituted by fluorine,

R9 is —C(O)—R10, —S(O) 2 —R14, —(CH 2 ) n —C(O)—R18 or —C(O)—(CH 2 ) m —R21 ,

R10 is phenyl or phenyl substituted by R13,

R13 is 1-4C-alkyl or 1-4C-alkoxy,

R14 is —N(R15)R16, phenyl or phenyl substituted by R17,

R15 is hydrogen or 1-4C-alkyl,

R16 is hydrogen or 1-4C-alkyl,

R17 is halogen, nitro, cyano, 1-4C-alkyl, 1-4C-alkoxy or 1-4C-alkoxy which is completely or predominantly substituted by fluorine,

R18 is —N(R19)R20,

R19 is hydrogen or 1-4C-alkyl,

R20 is hydrogen or 1-4C-alkyl,

or R19 and R20 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1-piperazinyl, 1-(1-4C-alkyl)-piperazin -4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl or 4-thiomorpholinyl-ring,

R21 is —N(R22)R23,

R22 is hydrogen or 1-4C-alkyl,

R23 is hydrogen or 1-4C-alkyl,

or R22 and R23 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1-piperazinyl, 1-(1-4C-alkyl)-piperazin-4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl, 4-thiomorpholinyl-, pyrrolidin-2,5-dione-1-yl-, morpholin-3, 5-dione-4-yl-, piperidin-2,6-dione-1-yl, 4,4-dimethyl -piperidin-2,6-dione-1-yl or a 1-methyl-imidazolidine -2,4-dione-3-yl-ring or a isoindol-1,3-dione-2-yl-ring -system,

n is an integer from 1 to 4,

m is an integer from 1 to 4,

or a salt thereof.

3. A compound of formula 1 according to claim 1 , in which

R1 is methyl or ethyl,

R2 is methyl or ethyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is methoxy, ethoxy or difluoromethoxy,

R5 is methoxy, ethoxy or difluoromethoxy,

R9 is —C(O)—R10,

R10 is phenyl or phenyl substituted by R13,

R13 is 1-4C-alkyl or 1-4C-alkoxy,

or a salt thereof.

4. A compound of formula 1 according to claim 1 , in which

R1 is methyl or ethyl,

R2 is methyl or ethyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is methoxy, ethoxy or difluoromethoxy,

R5 is methoxy, ethoxy or difluoromethoxy,

R9 is —S(O) 2 —R14,

R14 is —N(R15)R16, phenyl or phenyl substituted by R17,

R15 is hydrogen or 1-4C-alkyl,

R16 is hydrogen or 1-4C-alkyl,

R17 is halogen, nitro, cyano, 1-4C-alkyl, 1-4C-alkoxy or 1-4C-alkoxy which is completely or predominantly substituted by fluorine,

or a salt thereof.

5. A compound of formula 1 according to claim 1 , in which

R1 is methyl or ethyl,

R2 is methyl or ethyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is methoxy, ethoxy or difluoromethoxy,

R5 is methoxy, ethoxy or difluoromethoxy,

R9 is —(CH 2 ) n —C(O)—R18,

R18 is —N(R19)R20,

R19 is hydrogen or 1-4C-alkyl,

R20 is hydrogen or 1-4C-alkyl,

or R19 and R20 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1-piperazinyl, 1-(1-4C-alkyl)-piperazin - 4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl or 4-thiomorpholinyl-ring,

n is 1 or 2,

or a salt thereof.

6. A compound of formula 1 according to claim 1 , in which

R1 is methyl or ethyl,

R2 is methyl or ethyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is methoxy, ethoxy or difluoromethoxy,

R5 is methoxy, ethoxy or difluoromethoxy,

R9 is —C(O)—(CH 2 ) m —R21,

R21 is —N(R22)R23,

R22 is hydrogen or 1-4C-alkyl,

R23 is hydrogen or 1-4C-alkyl,

or R22 and R23 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1-piperazinyl, 1-methyl-piperazin-4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl, 4-thiomorpholinyl-, pyrrolidin-2,5-dione-1-yl-, morpholin-3,5-dione-4-yl-, piperidin-2,6-dione-1-yl, 4,4-dimethyl-piperidin-2,6-dione-1-yl or a 1-methyl-imidazolidine-2,4-dione-3-yl -ring or a isoindol-1,3-dione-2-yl-ring-system,

m is 1,

or a salt thereof.

7. A compound of formula 1 according to claim 1 , in which

R1 is methyl or ethyl,

R2 is methyl or ethyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is methoxy or ethoxy,

R5 is methoxy or ethoxy,

R9 is —C(O)—R10,

R10 is phenyl or phenyl substituted by R13,

R13 is methoxy,

or a salt thereof.

8. A compound of formula 1 according to claim 1 , in which

R1 is methyl or ethyl,

R2 is methyl or ethyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is methoxy or ethoxy,

R5 is methoxy or ethoxy,

R9 is —S(O) 2 —R14,

R14 is —N(R15)R16, phenyl or phenyl substituted by R17,

R15 is methyl,

R16 is methyl,

R17 is cyano, methyl, methoxy or trifluoromethoxy,

or a salt thereof.

9. A compound of formula 1 according to claim 1 , in which

R1 is methyl or ethyl,

R2 is methyl or ethyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is methoxy or ethoxy,

R5 is methoxy or ethoxy,

R9 is —(CH 2 ) n —C(O)—R18,

R18 is —N(R19)R20,

R19 is hydrogen,

R20 is hydrogen,

or R19 and R20 together and with inclusion of the nitrogen atom to which they are bonded, form a 4-morpholinyl-ring,

n is 1 or 2,

or a salt thereof.

10. A compound of formula 1 according to claim 1 , in which

R1 is methyl or ethyl,

R2 is methyl or ethyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is methoxy or ethoxy,

R5 is methoxy or ethoxy,

R9 is —C(O)—(CH 2 ) m —R21,

R21 is —N(R22)R23,

or R22 and R23 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-methyl-piperazin -4-yl-, pyrrolidin-2,5-dione-1-yl- or a morpholin-3,5-dione-4-yl-ring or a isoindol-1,3-dione-2-yl-ring-system,

m is 1,

or a salt thereof.

11. A compound of formula 1 according to claim 1 , in which

R1 is 1-4C-alkyl and

R2 is 1-4C-alkyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is 1-4C-alkoxy or 1-4C-alkoxy which is completely or predominantly substituted by fluorine,

R5 is 1-8C-alkoxy, 3-7C-cycloalkoxy, 3-7C-cycloalkylmethoxy, or 1-4C-alkoxy which is completely or predominantly substituted by fluorine,

R9 is —C(O)R10, —S(O) 2 —R14, —(CH 2 ) n —C(O)—R18 or —C(O)—(CH 2 ) m —R21, R10 is 1-4C-alkyl, —N(R11)R12, phenyl or phenyl substituted by R13,

R11 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

R12 is hydrogen, 1-4C-alkyl,3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

or R11 and R12 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1-piperazinyl, 1-(1-4C-alkyl)-piperazin-4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl, 4- thiomorpholinyl-, thiomorpholin-1-oxide-4-yl- or thiomorpholin-1,1-dioxide-4-yl-ring,

R13 is hydroxyl, halogen, nitro, cyano, hydroxycarbonyl, 1-4C-alkyl, trifluoromethyl, 1-4C-alkoxy, 1-4C-alkoxy which is completely or predominantly substituted by fluorine, 1-4C-alkoxycarbonyl, amino, mono- or di-1-4C-alkylamino, aminocarbonyl, mono- or di1-4C-alkylaminocarbonyl, 1-4C-alkylcarbonyl, 1-4C-alkylcarbonylamino or 1-4C-alkylcarbonyloxy,

R14 is 1-4C-alkyl, —N(R15)R16, phenyl or phenyl substituted by R17,

R15 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

R16 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

or R15 and R16 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1piperazinyl, 1-(1-4C-alkyl)-piperazin -4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl, 4-thiomorpholinyl-, thiomorpholin-1-oxide-4-yl- or thiomorpholin-1,1-dioxide-4-yl-ring,

R17 is hydroxyl, halogen, nitro, cyano, carboxyl, 1-4C-alkyl, trifluoromethyl, 1-4C-alkoxy, 1-4C-alkoxy which is completely or predominantly substituted by fluorine, 1-4C-alkoxycarbonyl, amino, mono- or di-1-4C-alkylamino, aminocarbonyl, mono- or di-1-4C-alkylaminocarbonyl, 1-4C-alkylcarbonyl, 1-4C-alkylcarbonylamino or 1-4C-alkylcarbonyloxy,

R18 is —N(R19)R20,

R19 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

R20 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

or R19 and R20 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1-piperazinyl-, 1-(1-4C-alkyl)-piperazin-4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl, 4-thiomorpholinyl-, thiomorpholin-1-oxide-4-yl- or thiomorpholin-1,1 -dioxide-4-yl-ring,

R21 is —N(R22)R23,

R22 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

R23 is hydrogen, 1-4C-alkyl, 3-7C-cycloalkyl or 3-7C-cycloalkylmethyl,

or R22 and R23 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1piperazinyl, 1 -(1-4C-alkyl)-piperazin -4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl, 4-thiomorpholinyl-, thiomorpholin-1-oxide-4-yl-, thiomorpholin-1,1-dioxide-4-yl- or a pyrrolidin-2,5-dione-1-yl-ring,

n is an integer from 1 to 4,

m is an integer from 1 to 4,

or a salt thereof.

12. A compound of formula 1 according to claim 1 , in which

R1 is 1-4C-alkyl,

R2 is 1-4C-alkyl,

R3 represents a phenyl derivative of formulae (a)

wherein

R4 is 1-2C-alkoxy or 1-2C-alkoxy which is completely or predominantly substituted by fluorine,

R5 is 1-4C-alkoxy,

R9 is —S(O) 2 —R14, —(CH 2 ) n —C(O)—R18 or —C(O)—(CH 2 ) m —R21,

R14 is phenyl or phenyl substituted by R17,

R17 is halogen, nitro, cyano, 1-4C-alkyl or 1-4C-alkoxy,

R18 is —N(R19)R20,

R19 is hydrogen or 1-4C-alkyl,

R20 is hydrogen or 1-4C-alkyl,

or R19 and R20 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1-piperazinyl, 1-(1-4C-alkyl)-piperazin -4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl or 4-thiomorpholinyl-ring,

R21 is —N(R22)R23,

R22 is hydrogen or 1-4C-alkyl,

R23 is hydrogen or 1-4C-alkyl,

or R22 and R23 together and with inclusion of the nitrogen atom to which they are bonded, form a 1-pyrrolidinyl-, 1-piperidinyl-, 1-piperazinyl, 1-(1-4C-alkyl)-piperazin-4-yl-, 1-hexahydroazepinyl-, 4-morpholinyl, 4-thiomorpholinyl- or a pyrrolidin-2,5-dione-1-yl-ring,

n is an integer from 1 to 4,

m is an integer from 1 to 4,

or a salt thereof.

13. A compound of formula 1 according to claim 1 , in which

R1 is methyl,

R2 is methyl,

R3 represents a phenyl derivative of formula (a)

wherein

R4 is methoxy or ethoxy,

R5 is methoxy or ethoxy,

R9 is —S(O) 2 —R14, —(CH 2 ) n —C(O)R18 or —C(O)—(CH 2 ) m —R21,

R14 is 2-cyanophenyl,

R18 is amino or 4-morpholinyl,

R21 is pyrrolidin-2,5-dione-1-yl,

n is 1 or 2,

m is 1,

or a salt thereof.

14. A pharmaceutical composition comprising one or more compounds according to claim 1 , or a pharmaceutically acceptable salt thereof, together with a pharmaceutically acceptable auxiliary and/or carrier.