The invention relates to compounds of formula I and to their physiologically acceptable salts and solvates which act as phosphodiesterse VII inhibitors and are thus useful for the treatment of allergic disorders, asthma, chronic bronchitis, atopic dermatitis, psoriasis and other skin disorders, inflammatory disorders, autoimmune diseases, rheumatoid arthritis, multiple sclerosis, Crohn's disease, diabetes mellitus or ulcerative colitis, osteoporosis, transplant rejection reactions, cachexia, tumor growth, tumor metastases, sepsis, memory disturbances, atherosclerosis and AIDS.