Resistance to current treatments of cancer encourages finding new therapeutical targets. The heat shock protein 90 (hsp90) is a molecular chaperon which regulates the folding of many client proteins associated with all of the six hallmarks of cancer, and helps maintaining their proper conformation. Consequently, the hsp90 has become an exciting new target in cancer drug discovery since the inhibition of its ATPase activity leads to depletion of these client proteins via the proteasomal pathway. PU3 and PU24S are purine-based hsp90 inhibitors functionalized on C-8 position. In the aim to identify more active compounds and/or new subfamilies of inhibitors, we have developed new metal-catalyzed C-H activation processes of various heterocycles including purines and other azoles. These new and simple approaches have allowed the access to numerous C-8 functionalized purines bearing (het)aryl, alkenyl and benzyl moieties.
