Abstract: Compounds of formula ##STR1## where A is usually carbonyl or --CH.sub.2 --, D is usually --CH.sub.2 --; R.sup.1 and R.sup.2 are independently hydrogen or optionally-substituted C.sub.1-4 alkyl or aryl, or R.sup.1 and R.sup.2 are joined together to form a monocyclic or bicyclic ring system, are HIV protease inhibitors. These compounds are useful in the prevention or treatment of infection by HIV and in the treatment of AIDS, either as compounds, pharmaceutically acceptable salts, pharmaceutical composition ingredients, whether or not in combination with other antivirals, immunomodulators, antibiotics or vaccines. Methods of treating AIDS and methods of preventing or treating infection by HIV are also described.

Abstract: Compounds of formula ##STR1## where R.sup.1 and R.sup.2 are independently hydrogen or optionally-substituted C.sub.1-4 alkyl or aryl, and R.sup.1 also forms a heterocycle or heterocycle-C.sub.1-4 alkyl, are HIV protease inhibitors. These compounds are useful in the prevention or treatment of infection by HIV and in the treatment of AIDS, either as compounds, pharmaceutically acceptable salts, pharmaceutical composition ingredients, whether or not in combination with other antivirals, immunomodulators, antibiotics or vaccines. Methods of treating AIDS and methods of preventing or treating infection by HIV are also described.

Abstract: Compounds of formula ##STR1## where R.sup.1 and R.sup.2 are independently hydrogen or optionally-substituted C.sub.1-4 alkyl or aryl, or R.sup.1 and R.sup.2 are joined together to form a monocyclic or bicyclic ring system, are HIV protease inhibitors. These compounds are useful in the prevention or treatment of infection by HIV and in the treatment of AIDS, either as compounds, pharmaceutically acceptable salts, pharmaceutical composition ingredients, whether or not in combination with other antivirals, immunomodulators, antibiotics or vaccines. Methods of treating AIDS and methods of preventing or treating infection by HIV are also described.

Abstract: Compounds of formula ##STR1## where R.sup.1 and R.sup.2 are independently hydrogen or optionally-substituted C.sub.1-4 alkyl or aryl, or R.sup.1 and R.sup.2 are joined together to form a monocyclic or bicyclic ring system, are HIV protease inhibitors. These compounds are useful in the treatment of infection by HIV and in the treatment of AIDS, either as compounds, pharmaceutically acceptable salts, pharmaceutical composition ingredients, whether or not in combination with other antivirals, immunomodulators, antibiotics or vaccines. Methods of treating AIDS and methods of treating infection by HIV are also described.