The present invention provides HTV aspartyl protease inhibitors of the formula; and when the compound of formula I comprises an amino group, pharmaceutically acceptable ammonium salts thereof, wherein n is 3 or 4, wherein R 1 may be, for example, iso-butyl, wherein X and Y, same or different, may be, for example, NH 2 and F, and wherein R 2 and R 3 are as defined herein.