PYRIDAZINONE DERIVATIVES AND THEIR USE AS PDE4 INHIBITORS

WIPO Patent Application WO2005075437

A8

Compounds of formula (1) are effective PDE4 inhibitors in which R1 is 1-4C-alkyl and R2 is 1-4C-alkyl, R3 represents a phenyl dervative of formulae (a) or (b) 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, R6 is 1-4C-alkoxy, 3-5C-cycloalkoxy, 3-5C-cycloalkylmethoxy, or 1-4C-alkoxy which is completely or predominantly substituted by fluorine, R7 is 1-4C-alkyl and R8 is hydrogen or 1-4C-alkyl, or wherein R7 and R8 together and with inclusion of the two carbon atoms, to which they are bonded, form a spiro-linked 5-, 6- or 7-membered hydrocarbon ring, optionally interrupted by an oxygen or sulphur atom and R9 is hydroxyl, halogen, nitro, cyano, 1-4C-alkyl, trifluoromethyl, 1-4C-alkoxy, 1-4C-alkoxy which is completely or predominantly substituted by fluorine, hydroxycarbonyl, hydroxycarbonyl-1-4C-alkyl, 1-4C-alkoxycarbonyl, 1-4C-alkylcarbonyl, 1-4C-alkylcarbonylamino, 1-4C-alkylcarbonyloxy, 1-4C-alkylsulfonyl, benzyloxy, -C(O)R10, -S(O)