"hydroxy-6-heteroarylphenanthridines and their use as pde4 inhibitors". compounds of formula (I), wherein: R1 is hydroxyl, 1-4c-alkoxy, 3-7c-cycloalkylmethoxy, 2,2-difluoroethoxy or completely or predominantly fluoro-substituted 1-4c-alkoxy, R2 is hydroxyl, 1-4c- alkoxy, 3-7c-cycloalkylmethoxy, 2,2-difluoroethoxy or 1-4c-fully or predominantly fluoro-substituted alkoxy or wherein: r1 and r2 together are a 1-2c-alkylenedio group, r3 is hydrogen or 1-4c- alkyl, r31 is hydrogen or 1-4c alkyl, or in a first embodiment (embodiment a) according to the present invention, r4 is -o-r41, wherein: r41 is hydrogen, 1-4c alkyl, 1-4c alkoxy -14c-alkyl, hydroxy-2-4c-alkyl, 1-7c alkylcarbonyl or completely or predominantly fluoro-substituted 1-4c-alkyl and R5 is hydrogen or 1-4c alkyl, or in a second embodiment (modality b) according to with the present invention, r4 is hydrogen or 1-4c-alkyl and r5 is -o-r51, wherein r51 is hydrogen, 1-4c-alkyl, 1-4c-alkoxy-1-4c-alkyl, hydroxy-2- 4c-alkyl, 1-7c-alkylcarb completely or predominantly fluoro-substituted 1-4C-alkyl or har, is optionally substituted by r6 and / or r7 and / or r8 and is a monocyclic or bicyclic fused unsaturated or partially saturated heteroaryl radical of 5 to 10 elements comprising 1 to 4 Selected heteroatoms independently of the group consisting of oxygen, nitrogen and sulfur are new effective inhibitors of pde4."hodróxi-6-heteroarilfenantridinas e seu uso como inibidores de pde4". compostos da fórmula (i), na qual: r1é hidroxila, 1-4c-alcóxi, 3-7c-cicloalquilmetóxi, 2,2-difluoroetóxi ou 1-4c-alcóxi completa ou predominantemente flúor-substituído, r2é hidroxila, 1-4c-alcóxi, 3-7c-cicloalquilmetóxi, 2,2- difluoroetóxi ou 1-4c-alcóxi completa ou predominantemente flúor-substituído ou na qual: r1 e r2 juntos são um grupo 1-2c-alquilenodió, r3 é hidrogênio ou 1-4c-alquila, r31 é hidrogênio ou 1-4c alquila, ou em uma primeira modalidade (modalidade a) de acordo com a presente invenção, r4 é -o-r41, no qual: r41 é hidrogên
