Camptothecin derivatives, preparations thereof and antitumor agents

摘要

New camptothecin derivatives of the general formula (1), preparations thereof and antitumor agents comprising the same, wherein R<1> represents a hydrogen atom or a C1-C6 alkyl group, R<2> represents a hydrogen or a C1-C6 alkoxy group, R<3> represents a hydrogen or halogen atom or a C1-C6 alkyl, C1-C6 alkoxy, hydroxyl, C2-C6 acyloxy or methoxyethoxymethoxy group, R<4> represents a hydrogen or halogen atom, and R<5> represents a C1-C6 alkyl, C3-C6 unsaturated alkyl, alkylthioalkyl, alkoxyalkyl, pyridyl or substituted phenyl group, with the proviso that all of the R<2>, R<3> and R<4> substituents should not be a hydrogen atom.