TRISUBSTITUTED PYRIMIDO[5,4-D]PYRIMIDINES FOR MODULATING MULTI-DRUG RESISTANCE, PHARMACEUTICAL COMPOSITIONS CONTAINING THESE COMPOUNDS AND PROCESSES FOR THEIR PREPARATION

摘要

Pyrimido Pyrimidine Compounds The invention relates to compounds of formula I <IMG> (I) (wherein Ra, Rb and Rc are as defined in claim 1) and the salts thereof, more particularly for pharmaceutical use the physiologically acceptable salts thereof, which have, inter alia, valuable pharmacological properties, particularly a sensitising effect on resistant tumours in chemotherapy, their use and processes for their preparation.