Method of inhibiting protease

A method for inhibiting HIV protease in a subject in need thereof, comprising the step of administering to said subject a compound of the following formula I, or a pharmaceutically acceptable salt thereof, in an amount effective therefor:

• ##STR883## where A.sup.c is hydrogen or alkyl;
• A.sup.a and A.sup.b are independently ##STR884## where R.sup.5, R.sup.6 and R.sup.7 are independently hydrogen, alkyl, aryl, carbocyclo, fluorenyl, alkynyl or alkenyl, and Z is oxygen or sulfur;
• D.sup.a and D.sup.b are independently selected from groups of the formula:
• ##STR885## where D.sup.a and D.sup.b are bonded to the groups A.sup.a and A.sup.b, respectively, through the moiety --E--N(R.sup.8)--, where E is a single bond;
• R.sup.1 and R.sup.2 are independently:
• (1) hydrogen;
• (2) alkyl;
• (3) alkenyl;
• (4) aryl;
• or
• (5) carbocyclo;
• R.sup.8 is:
• (a) hydrogen;
• or
• (b) alkyl;
• R.sup.9 in one of D.sup.a or D.sup.b is:
• (a) hydrogen;
• (b) alkyl;
• (c) alkenyl;
• (d) alkynyl;
• (e) aryl;
• (f) carbocyclo;
• or
• (g) arylalkyl;
• and, in the other of D.sup.a or D.sup.b, R.sup.9 is alkyl substituted by aryl, where said aryl is itself substituted by morpholinylcarbonylalkoxy or piperidinylcarbonylalkoxy;
• R.sup.9 ' is:
• (a) hydrogen;
• (b) alkyl;
• (c) alkenyl;
• (d) alkynyl;
• (e) aryl;
• or
• (f) carbocyclo;
• R.sup.10 is:
• (a) hydrogen;
• (b) alkyl;
• (c) alkenyl;
• (d) alkynyl;
• (e) carbocyclo;
• or
• (f) aryl;
• R.sup.11 is:
• (a) hydrogen;
• or
• (b) a hydroxyl protecting group;
• p and q are, independently, integers from 0 to 4;
• the terms "alk" or "alkyl", where they appear alone or as part of another group, denote a straight or branched chain saturated radical containing 1 to 12 carbons in the normal chain;
• the term "alkenyl" denotes a straight or branched chain radical containing 2 to 12 carbons in the normal chain which contains at least one carbon to carbon double bond and which is directly attached through one of the carbons composing said double bond;
• the term "alkynyl" denotes a straight or branched chain radical containing 2 to 12 carbons in the normal chain which contains at least one carbon to carbon triple bond and which is directly attached through one of the carbons composing said triple bond;
• term "carbocyclo" denotes a saturated or partially unsaturated, homocyclic carbon ring system containing from 1 to 3 rings and from 3 to 12 carbons per homocyclic ring;
• and
• the term "aryl", where it appears alone or as part of another group, denotes a homocyclic, aromatic group containing 1 or 2 rings and from 6 to 12 carbons.