Medicinal chemistry of Hsp90 inhibitors

Heat shock protein (Hsp90) inhibitors are an increasingly interesting and important class of compounds where the first in class, natural product derived inhibitors such as 17-allylaminogeldanamycin (17-AAG), are entering late stage clinical development. Recently the emergence of synthetic, small molecule inhibitors has been described and both NVP-AUY922 and BIIB021 have entered clinical development. The medicinal chemistry of these and other published small molecule Hsp90 inhibitors is described in this review.