The present invention provides compounds for treating or preventing an HIV infection, or treating AIDS or ARC comprising administering a compound according to formula I where Ar, R.sup.1--R.sup.5, R.sup.7a, R.sup.7b, R.sup.7c, R.sup.8--R.sup.10, X.sup.1, X.sup.2 m, n, o and p are as defined herein ##STR00001##