The present invention provides compounds of the formula: or pharmaceutically acceptable salts, solvates or prodrugs thereof, wherein p, Ar, R.sup.1, R.sup.2, R.sup.3, R.sup.a, R.sup.b, R.sup.c, R.sup.d and R.sup.e are defined herein. Also provided are pharmaceutical compositions, methods of using, and methods of preparing the compounds.