#$%^&*AU2013204891A120130516.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. NH2 X NH2 X2 X4 e Xc XC R Xb R Xb-Xd NH2 X - -Y x~Z 2 XN, 5 R OR1 Z1-Z3, Xa-Xc X2, X4, Y and R are as defined in the specification.