Serine protease inhibitors-tripeptoid analogs

A compound of the formula:

• ##STR34## wherein X and Y are each O, N, or S , provided that at least one of X or Y is N;
• R.sub.1 is (C.sub.5 -C.sub.12)aryl, (C.sub.5 -C.sub.12)arylalkyl, (C.sub.5 -C.sub.12)arylalkenyl, fused (C.sub.5 -C.sub.12)aryl-cycloalkyl, alkyl fused (C.sub.5 -C.sub.12)aryl-cycloalkyl or alkenyl fused (C.sub.5 -C.sub.12)aryl-cycloalkyl optionally comprising one or more heteroatoms selected from N, S, or non-peroxide O;
• and optionally substituted with alkyl, halo, haloalkyl, amino, alkylamino or dialkylamino;
• R.sub.2 and R.sub.3 are independently or together H or alkyl;
• A is a direct bond, --C(O)--, --NH--C(O)--, --S(O).sub.2 --, --OC(O)-- or --CH.sub.2 --;
• and
• R.sub.4 is H, alkyl or alkenyl;
• or cycloalkyl, aryl or arylalkyl optionally comprising one or more heteroatoms selected from N, O and S, provided that not more than three of the following conditions are satisfied:
• (i) X and Y are independently O or N,
• (ii) R.sub.1 is .alpha.,.alpha.-dialkylalkylaryl or .alpha.,.alpha.-dialkylalkyl fused aryl-cycloalkyl wherein the cycloalkyl group is optionally substituted with two or more O atoms;
• (iii) R.sub.2 and R.sub.3 are independently H or alkyl;
• (iv) --A--R.sub.4 are together an alkoxycarbonyl;
• and
• further provided that not more than two of the following conditions are satisfied:
• (i) at least one of R.sub.2 or R.sub.3 is hydrogen;
• (ii) R.sub.1 is selected from a phenyl, phenylalkenyl;
• or phenylalkyl optionally substituted with halogen, haloalkyl, amino, aminoalkyl, dialkylamino, alkyl;
• or from a heteroaryl, heteroarylalkyl or heteroarylalkenyl wherein the heteroaryl group is a monocyclic five or six membered ring containing one or two heteroatoms independently selected from O, S and N, and optionally substituted with halogen, haloalkyl, amino, aminoalkyl, dialkylamino, alkyl;
• and
• (iii) R.sub.4 --A-- is a structure of the formula:
• Ph--CH.sub.2 --O--C(O)--, where Ph is an unsubstituted phenyl group and C(O) represents a carbonyl group.