Overexpression of CK1δ has been associated to the development of cancer and neurodegenerative disorders, making ligands of this protein very promising drug candidates for the treatment these diseases and/or pharmacological tools for their study. A screening campaign of an in-house adenine derivative library revealed that some compounds are able to inhibit the CK1δ enzyme isoform with IC50 in the low μM range. Molecular docking analyses were performed at a X-ray structure of the enzyme, leading to the rational design of novel di- and tri-substituted adenines that were synthesized and characterized. Biological evaluation demonstrated that the new compounds are endowed with moderate CK1δ inhibitory activity. In particular, the 2-amino-9-benzyladenine (12) and its 8-bromo derivative 14, tested at a concentration of 40 μM, inhibited the enzyme leaving a residual activity of about 35% and 42%, respectively. Docking studies provided an interpretation of these data, with suggestions for a further development of these compounds to achieve more potent CK1δ inhibitors.
