In order to obtain the product of the general formula (I') wherein R3' is an amino group, 10-nitrocamptothecin, its tetrahydro derivative or its 1-acyl-tetrahydro derivative is subjected to a conventional reductive reaction contemplated for reducing a nitro group to an amino group. Usually, Clemensen' reduction method (a combination of dilute mineral acid and tin, iron or zinc) or a catalytic reduction method is used for this purpose. Advantageously, 10-nitrocamptothecin is dissolved in a solvent and hydrogenated at room temperature under atmospheric pressure in the presence of a small amount of platinum oxide. In this case, the desired 10-aminocamptothecin can be obtained by removing the catalyst from the reaction mixture by filtration and evaporating the solvent under reduced pressure.
