The disclosure relates to Compounds of Formulae (IA) and (IB), and pharmaceutically acceptable salts thereof wherein Z1, Z2, Z3, Xa, Xb, Xc, Xd, Y, X2, and X4 are as defined herein, compositions comprising an effective amount of a Compound of Formula (IA) and/or (IB), and methods to treat or prevent a condition, such cancer which overexpresses Her-kinases, comprising administering to an patient in need thereof a therapeutically effective amount of a Compound of Formula (IA) or (IB). The disclosure further relates to compounds of Formulae (IA) and (IB) in which X2 is a leaving for introducing a radiolabeled atom, such as 124I or 131I and to methods of using such compounds in the preparation of radiolabeled compounds, particularly for use in imaging.
