The present invention relates to indolinone derivatives, substituted in the 6-position, of the formula ##STR00001## in whichR.sup.1 to R.sup.6 and X are as defined in claim 1, to their tautomers, enantiomers, diastereomers, to their mixtures and to their salts, in particular their physiologically acceptable salts, which have useful pharmacological properties, in particular in inhibiting action on various receptor tyrosine kinases and on the proliferation of endothelial cells and various tumour cells, to medicaments comprising these compounds, to their use and to processes for their preparation.