| abstract |
Compounds of the formula I, in which R3 denotes hydrogen, hydroxyl, nitro, amino, carboxyl, aminocarboxyl, 1-4C-alkoxy, trifluoromethoxy, 1-4C-alkoxycarbonyl or mono- or dl-1-4C-alkylaminocarbonyl and R4 denotes C(O)-X-R5, N(H)-C(O)-R6 or N(H)-C(O)-N(H)-R7, in which X denotes O or N(H), are effective PDE7 inhibitors. |