Disclosed are chemical compounds, the compounds for use 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.