To improve the antitumor properties and optimize the pharmaceutical properties including solubility and protein binding of indolin-2-ones, a number of different basic and weakly basic analogues were designed and synthesized. 5-[5-Fluoro-2-oxo-1, 2-dihydroindol-(3 Z)- ylidenemethyl]-2, 4-dimethyl-1 H-pyrrole-3-carboxylic acid (2-diethylaminoethyl) amide (12b or SU11248) has been found to show the best overall profile in terms of potency for the ...