| abstract |
New camptothecin derivatives of the general formula:n wherein R 1 and R 2 each stands for a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group or a substituted or unsubstituted aryl group and R and R 2 , taken together with the nitrogen atom to which they are attached, may form a cyclic group. These new derivatives are useful intermediates for preparing pharmaceuticals or other classes of new camptothecin derivatives. These present new derivatives are prepared by treating camptothecin-7--carboxylic acid first with a carboxyl group-activating reagent and then with ammonia or the corresponding amine. |