BETA-LACTAMASE INHIBITORS

1 - 83 . (canceled)

84 . A compound of Formula (A-I) or a pharmaceutically acceptable salt thereof:

wherein X* is O;

R* is

and

R 1* is selected from:

a. hydrogen;

b.

wherein R 2* is selected from

R 3* is selected from hydrogen, (C 1 -C 3 )-alkyl, aminoalkyl, aminocycloalkyl, hydroxyalkyl,

each of R 4* , R 5* , R 6* and R 7* is independently selected from hydrogen or (C 1 -C 6 )-alkyl, aminoalkyl, aminocycloalkyl, and hydroxyalkyl, provided that at least one of R 4* , R 5* , R 6* and R 7* is hydrogen,

n is selected from 1, 2, 3 and 4,

m is selected from 1, 2 and 3; and

c. wherein Z is selected from CR 12 R 13 or NR 14 ,

each of R 12 and R 13 is independently selected from H, NH 2 and

wherein each of R 4* , R 5* , R 6* and R 7* is as described previously,

alternatively, R 12 and R 13 together with the carbon to which they are attached, form a cycloalkyl or heterocyclyl ring containing 4-6 ring members,

R 14 is selected from H and

wherein each of R 15 , R 16 and R 17 is independently selected from hydrogen, (C 1 -C 6 )-alkyl, aminoalkyl, aminocycloalkyl, and hydroxyalkyl, provided that at least one of R 15 , R 16 and R 17 is hydrogen,

R 18 is selected from NH 2 and

wherein each of R 4* , R 5* , R 6* and R 7* is as described previously,

each of p* and q* is independently selected from 0, 1, 2 and 3,

T is selected from NH and O

t is selected from 0, 1, 2, 3, and 4, and

each of r and y is independently selected from 0 and 1.

85 . The compound of claim 84 selected from the group consisting of:

86 . A pharmaceutical composition comprising a compound of claim 84 and at least 1 β-lactam antibiotic.

87 . The pharmaceutical composition of claim 86 wherein the β-lactam antibiotic is a cephalosporin.

88 . The pharmaceutical composition of claim 86 wherein the β-lactam antibiotic is a carbapenem.

89 . The pharmaceutical composition of claim 86 wherein the β-lactam antibiotic is a monobactam.