Pyrrolopyrimidine derivatives of the formula I ##STR00001## in which R.sup.3, R.sup.4, R.sup.5, R.sup.6 and X are as defined in claim 1, act as phosphodiesterase VII inhibitors and can be employed for the treatment of osteoporosis, tumours, cachexia, atherosclerosis, rheumatoid arthritis, multiple sclerosis, diabetes mellitus, inflammatory processes, allergies, asthma, autoimmune diseases, myocardial diseases and AIDS.