In vitro cytotoxicity of 5-aminosubstituted 20(S)-camptothecins. Part 1.

A number of 5-aminosubstituted 20(S)-camptothecin analogues were prepared via semi-synthesis starting from 20(S)-camptothecin and 9-methoxy 20(S)-camptothecin. In vitro anti-cancer activity of these analogues was determined using 60 human tumor cell line assay. Although water solubility of most of these compounds was improved compared to 20(S)-camptothecin, their anti-cancer activity was considerably diminished. However, only smaller substituents such as methylamine or hydroxylamine as present in 8s and 8t, respectively, showed good activity with improved water solubility.