Retroviral protease inhibiting compounds

A compound of the formula:

• ##STR17## wherein R.sub.2 and R.sub.3 are independently selected from C.sub.3 -to-C.sub.7 -cycloalkyl-C.sub.1 -to-C.sub.6 -alkyl and (C.sub.6 -monocyclic or C.sub.9 - or C.sub.10 -bicyclic)aryl-C.sub.1 -to-C.sub.6 -alkyl;
• and
• (a) A is thiazolyl-C.sub.1 -to-C.sub.6 -alkyl-R.sub.9 --C(O)--NH--CH(R.sub.5)--C(O)-- or (substituted-thiazolyl)-C.sub.1 -to-C.sub.6 -alkyl-R.sub.9 --C(O)--NH--CH(R.sub.5)--C(O)-- wherein R.sub.9 is --O--, --NH-- or --N(C.sub.1 -to-C.sub.6 -loweralkyl)- and R.sub.5 is C.sub.1 -to-C.sub.6 -loweralkyl and B is thiazolyl-C.sub.1 -to-C.sub.6 -alkyl-O--C(O)--, thiazolyl-C.sub.1 -to-C.sub.6 -alkyl-NH--C(O)--, thiazolyl-C.sub.1 -to-C.sub.6 -alkyl-N(C.sub.1 -to-C.sub.6 -loweralkyl)-C(O)--, (substituted-thiazolyl)-C.sub.1 -to-C.sub.6 -alkyl-O--C(O)--, (substituted-thiazolyl)-C.sub.1 -to-C.sub.6 -alkyl-NH--C(O)-- or (substituted-thiazolyl)-C.sub.1 -to-C.sub.6 -alkyl-N(C.sub.1 -to-C.sub.6 -loweralkyl)-C(O)-- and wherein at each occurrence substituted-thiazolyl is independently selected from a thiazolyl ring substituted with one or two substituents independently selected from C.sub.1 -to-C.sub.6 -loweralkyl, hydroxy, halo, amino, C.sub.1 -to-C.sub.6 -alkylamino, di-C.sub.1 -to-C.sub.6 -alkylamino, C.sub.1 -to-C.sub.6 -alkoxy, halo-C.sub.1 -to-C.sub.6 -alkyl, unsubstituted-C.sub.3 -to-C.sub.7 -cycloalkyl, unsubstituted (C.sub.6 -monocyclic or C.sub.9 - or C.sub.10 -bicyclic)aryl, unsubstituted (C.sub.6 -monocyclic or C.sub.9 - or C.sub.10 -bicyclic)aryl-C.sub.1 -to-C.sub.6 -alkyl, --COOH and --SO.sub.3 H;
• or
• (b) A is thiazolyl-C.sub.1 -to-C.sub.6 -alkyl-O--C(O)--, thiazolyl-C.sub.1 -to-C.sub.6 -alkyl-NH--C(O)--, thiazolyl-C.sub.1 -to-C.sub.6 -alkyl-N(C.sub.1 -to-C.sub.6 -loweralkyl)-C(O)--, (substituted-thiazolyl)-C.sub.1 -to-C.sub.6 -alkyl-O--C(O)--, (substituted-thiazolyl)-C.sub.1 -to-C.sub.6 -alkyl-NH--C(O)-- or (substituted-thiazolyl)-C.sub.1 -to-C.sub.6 -alkyl-N(C.sub.1 -to-C.sub.6 -loweralkyl)-C(O)-- and B is thiazolyl-C.sub.1 -to-C.sub.6 -alkyl-R.sub.9 --C(O)--NH--CH(R.sub.5)--C(O)-- or (substituted-thiazolyl)-C.sub.1 -to-C.sub.6 -alkyl-R.sub.9 -C(O)--NH--CH(R.sub.5)--C(O)-- wherein R.sub.9 is --O--, --NH-- or --N(C.sub.1 -to-C.sub.6 -loweralkyl)- and R.sub.5 is C.sub.1 -to-C.sub.6 -loweralkyl and wherein at each occurrence substituted-thiazolyl is independently selected from a thiazolyl ring substituted with one or two substituents independently selected from C.sub.1 -to-C.sub.6 -loweralkyl, hydroxy, halo, amino, C.sub.1 -to-C.sub.6 -alkylamino, di-C.sub.1 -to-C.sub.6 -alkylamino, C.sub.1 -to-C.sub.6 -alkoxy, halo-C.sub.1 -to-C.sub.6 -alkyl, unsubstituted-C.sub.3 -to-C.sub.7 -cycloalkyl, unsubstituted (C.sub.6 -monocyclic or C.sub.9 - or C.sub.10 -bicyclic)aryl, unsubstituted (C.sub.6 -monocyclic or C.sub.9 - or C.sub.10 -bicyclic)aryl-C.sub.1 -to-C.sub.6 -alkyl, --COOH and --SO.sub.3 H;
• or a pharmaceutically acceptable salt thereof.