Abstract: Disclosed herein is a process for preparing (S)-.alpha.-amino-1-carboxycyclopentaneacetic acid which is a useful intermediate for preparing peptidomimetic inhibitors of herpes viral ribonucleotide reductase. The process comprises the preparation of the key intermediate ##STR1## and its subsequent conversion to the desired product.

Abstract: Disclosed herein are compounds which inhibit human immunodeficiency virus (HIV) protease activity and inhibit HIV replication in human cells. Thus, the compounds are indicated for the treatment of HIV infections. The compounds can be represented by the formula ##STR1## wherein X is a terminal group, for example, an aryloxycarbonyl, an alkanoyl or an arylalkyl carbamoyl; A is absent or an amino acid or a derived amino acid; either R.sup.1 or R.sup.2 is hydrogen while the other is alkyl or R.sup.1 and R.sup.2 are joined to form a cyclohexane; Q is hydrogen, hydroxy, halo or lower alkoxy; and Y is a terminal group, for example, an alkylamino, alkoxy or an optionally substituted anilino.