US Patent 7151179 Process for the preparation of 7-alkyl-10-hydroxy-20(S)-camptothecin

The key intermediate in any synthesis of Irinotecan is 7-ethyl-10-hydroxy-20(S)-camptothecin. A process for the efficient synthesis of this intermediate is demonstrated proceeding through readily available 20(S)-camptothecin. Various other tecan compounds may be made by use of corresponding 7-alkyl-10-hydroxy-20(S)-camptothecin intermediates.