The present invention relates to chemical compounds, the compounds for us in a method of treatment, particularly in a method of prophylaxis or treatment for cancer, a process for preparation of the compounds and pharmaceutical compositions comprising the compounds. The compounds may, in particular, be useful in the treatment of leukaemia, lymphoma and/or solid tumours in homo sapiens. The compounds are derivatives of cordycepin (3'-deoxyadenosine) having a 2' and/or 5'-amino-acid ester phosphoramidate moiety.