The present invention provides analogs of benzoquinone-containing ansamycins and uses thereof for treating and modulating disorders associated with hyperproliferation, such as cancer. The present invention provides analogs of benzoquinone-containing ansamycins where the benzoquinone is reduced to a hydroquinone and trapped by reaction with a suitable acid, preferably ones that increase the solubility and air stability of the resulting 17-ammonium hydroquinone ansamycin analog.