Disclosed are compounds of formulae (I), (III), (IV), (VII), (X), (XI), (XII), (XIII) and (XIV), wherein the variables are as defined in the claims, and methods of using compounds of the invention for treating a subject with a proliferative disorder, such as cancer, and methods for treating disorders responsive to Hsp70 induction and/or natural killer induction. Also disclosed are pharmaceutical compositions comprising compounds of the invention and a pharmaceutically acceptable carrier.