The present invention relates to heterocyclically substituted indolinones of general formula ##STR00001## wherein R.sub.1 to R.sub.5 and X are defined as in claim 1, the tautomers, the diastereomers, the enantiomers, the mixtures thereof, the prodrugs thereof and the salts thereof, particularly the physiologically acceptable salts thereof which have valuable pharmacological properties, in particular an inhibiting effect on various receptor tyrosine kinases and cyclin/CDK complexes and on the proliferation of endothelial cells and various tumour cells, pharmaceutical compositions containing these compounds, their use and processes for preparing them.