The present invention provides an aspartic proteinase-inhibiting compound of the formula: ##STR00001## wherein a, b, c, d, and e, can be the same or different and each are R.sup.7, OR.sup.7, SR.sup.7, NR.sup.7R.sup.8, NHCOR.sup.7, CO.sub.2R.sup.7, CN, NO.sub.2, NH.sub.2, N.sub.3, or a halogen, wherein R.sup.7 and R.sup.8 are independently H or an alkyl. Substituents R.sup.1 or R.sup.2 are each H or an alkyl. Substituent R.sup.3 is a straight chain or branched alkyl, alkenyl, or alkynyl substituent, or is a cycloalkyl. Substituent A is OH, NH.sub.2, or SH.Further provided are pharmaceutical compositions, which include a therapeutically effective amount of at least one of the foregoing compounds, and therapeutic methods of using the foregoing compounds.