#$%^&*AU2013204109B220160505.pdf#####ABSTRACT The present application provides substituted purine derivatives and related compounds of the formulae shown. These compounds are useful as inhibitors of HSP90, and hence in the treatment of related diseases. NH 2 NH 2 X -Y-O ,xa ) -yXa X4 Z2 Nkc x4 R2XNc R X R Xb-Xd NH 2 X 4 z2 N 5R OR1 Z1-Z3, Xa-Xc X 2, X4, Y and R are as defined in the specification.