The present invention relates to a method of inducing apoptosis in a tumour cell as well as modulating pluripotency and/or self-renewing characteristics of a stem/progenitor cell. The method comprises administering to the respective cell a compound of general formula (I). In general formula A is C or N. R1, R4 and R5 are, independently selected, H or aliphatic, cycloaliphatic aromatic, arylaliphatic, or arylcycloaliphatic hydrocarbyl groups, that comprise 0-3 heteroatoms being N, O, S, or Si. R4 and R5 may optionally be linked so as to define an aliphatic hydrocarbyl bridge. R2 is H or a halogen, such as F or Cl. R3 is H, or an aliphatic or arylaliphatic hydrocarbyl group comprising 1-8 main chain carbon atoms and 0-3 heteroatoms being N, O, S, Si, or a halogen such as Cl or F. Also provided is a pharmaceutical composition for inducing apoptosis in a tumour cell and/or modulating pluripotency and/or self-renewing characteristics of a stem/progenitor cell. The pharmaceutical composition comprises a compound as defined above or a pharmaceutically acceptable salt thereof and a carrier or diluent.