Chromane amidine monobactam compounds for the treatment of bacterial infections

1. A compound of Formula I

or a pharmaceutically acceptable salt thereof, wherein:

T is CH, or N, provided that no more than two of T, U and V are N;

U is CH, or N;

V is CH or N;

X is selected from:

1) O, and

2) CH 2 ;

Y is selected from:

1) O,

2) NR 8 ,

3) S, and

4) CH 2 ,

provided that when Y is O, NR 8 or S then X is not O;

Z is

1) O,

2) S,

3) CH 2 , or

4) NH,

provided that when Z is O, S or NH, then X is not O;

W is selected from:

1) bond, and

2) O;

Q is selected from:

1) N, and

2) CR 8 ;

R 1 is selected from:

1) —C 3-12 cycloalkyl,

2) —C 3-12 cycloalkenyl,

3) —C 2-11 cycloheteroalkyl,

4) —C 2-11 cycloheteroalkenyl,

5) aryl, and

6) heteroaryl,

wherein alkyl, cycloalkyl, cycloalkenyl, cycloheteroalkyl, cycloheteroalkenyl, aryl and heteroaryl are unsubstituted or substituted with one to five substituents selected from R a ;

R 2 is selected from:

1) hydrogen,

2) —C 1-6 alkyl,

3) —C 1-6 alkyl-OR 4 , and

4) —C 1-6 alkyl-NHR 4 ,

wherein alkyl is unsubstituted or substituted with one to three halogens;

R 3 is selected from:

1) hydrogen, and

2) OH;

R 4 is selected from:

1) hydrogen,

2) C 1-3 alkyl, and

3) C 3 cycloalkyl,

wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three halogens or OC 1-3 alkyl;

R 5 is selected from:

1) —CO 2 H, and

2) tetrazole;

R 6 and R 7 are selected from:

1) hydrogen, and

2) C 1-6 alkyl,

wherein alkyl is unsubstituted or substituted with one to three halogens, provided that at least one of R 6 and R 7 is hydrogen;

each R 8 is independently selected from:

1) hydrogen,

2) C 1-4 alkyl,

3) halogen, and

4) C 3-7 cycloalkyl,

wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three substituents selected from: —OH, halogen, NH 2 , and —OC 1-3 alkyl;

R 9 and R 10 are selected from:

1) hydrogen, and

2) C 1-6 alkyl,

wherein alkyl is unsubstituted or substituted with one to three substituents selected from:

halogen, OH, —OC 1-3 alkyl, —NHC(O)C 1-3 alkyl, —C(O)NHC 1-3 alkyl, NHC 1-3 alkyl, and SC 1-3 alkyl, provided that one or both of R 9 and R 10 are C 1-6 alkyl,

or alternatively R 9 and R 10 together with the carbon to which they are attached form a monocyclic C 3-5 cycloalkyl or a monocyclic C 2-5 cycloheteroalkyl, wherein cycloalkyl and cycloheteroalkyl are unsubstituted or substituted with one to three substituents independently selected from halogen, —OH and —OC 1-3 alkyl;

each R a is independently selected from:

1)halogen,

2) —C 1-6 alkyl,

3) —C 0-6 alkyl-O—C 1-6 alkyl,

4) —C 0-6 alkyl-OH,

5) —C 0-6 alkyl S(O) r R j ,

6) —C 0-6 alkyl S(O) r NR k R l ,

7) —C 0-6 alkyl C(O)R i ,

8) —C 0-6 alkyl OC(O)R i ,

9) —C 0-6 alkyl C(O)OR i ,

10) —C 0-6 alkyl CN,

11) —C 0-6 alkyl C(O)NR k R l ,

12) —C 0-6 alkyl C(NH)NR k R l ,

13) —C 0-6 alkylNR k R l ,

14) —C 0-6 alkyl N(R k )(C(O)R i ),

15) —C 0-6 alkyl N(R k )(C(O)OR h ),

16) —C 0-6 alkyl N(R k )(C(O)NR f R g ), and

17) —C 0-6 alkyl N(R k )(S(O) v R j ),

wherein alkyl is unsubstituted or substituted with one to three substituents selected from: halogen, OH, —OC 1-3 alkyl, —C 1-3 alkyl, —CO 2 C 1-3 alkyl, —C(O)NH 2 , —C 0-6 alkylNH 2 , and —C 0-6 alkylNH(C 1-3 alkyl);

each R b is independently selected from:

1) hydrogen,

2) —C 1-6 alkyl,

3) —C 0-6 alkyl-O—C 1-6 alkyl,

4) —C 0-6 alkyl-OH,

5) —C 0-6 alkyl-S(O) u R d ,

6) —C 1-6 alkyl-C(O—N(R e ) 2 ,

7) —C 1-6 alkylN(Re)C(O)R e ,

8) —C 0-6 alkyl-N(R e ) 2 , and

9) halogen,

wherein alkyl is unsubstituted or substituted with one to three halogens,

or optionally, two R b substituents, together with the atoms to which they are attached, can cyclize to form a monocyclic C 3-6 cycloalkyl or a monocyclic C 2-6 cycloheteroalkyl ring;

each R c is independently selected from:

1) hydrogen,

2) —C 1-6 alkyl,

3) —C 0-6 alkyl-O—C 1-6 alkyl,

4) —C 0-6 alkyl-OH,

5) —C 0-6 alkyl-S(O) v R f ,

6) —C 0-6 alkyl-S(O) v N(R g ) 2 ,

7) —C 1-6 alkyl C(O)—N(R g ) 2 ,

8) —C 1-6 alkylN(R g )C(O)R g ,

9) —C 0-6 alkyl-N(R g ) 2 , and

10) halogen,

wherein alkyl is unsubstituted or substituted with one to three halogens;

each R d is independently selected from:

1) hydrogen, and

2) —C 1-6 alkyl,

wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R e is independently selected from:

1) hydrogen, and

2) —C 1-6 alkyl,

wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R f is independently selected from:

1) hydrogen, and

2) —C 1-6 alkyl,

wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R g is independently selected from:

1) hydrogen, and

2) —C 1-6 alkyl,

wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R h is independently selected from:

1) hydrogen, and

2) —C 1-6 alkyl,

wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R i is —C 1-6 alkyl, wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R j is independently selected from:

1) hydrogen,

2) OH, and

3) —C 1-6 alkyl,

wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R k is independently selected from:

1) hydrogen, and

2) —C 1-6 alkyl,

wherein each alkyl is unsubstituted or substituted with one to three halogens;

each R l is independently selected from:

1) hydrogen, and

2) —C 1-6 alkyl,

wherein each alkyl is unsubstituted or substituted with one to three halogens;

each r is independently 0, 1 or 2;

each s is independently 0, 1, 2, 3, 4 or 5;

each t is independently 0, 1, 2 or 3;

each u is independently selected from 0, 1 or 2; and

each v is independently selected from 0, 1 or 2.

2. The compound of claim 1 wherein

T is CH;

U is CH; and

V is CH;

or a pharmaceutically acceptable salt thereof.

3. The compound of claim 1 wherein

X is CH 2 ;

or a pharmaceutically acceptable salt thereof.

4. The compound of claim 1 wherein

Y is O or CH 2 ; and

Z is O or CH 2 ;

or a pharmaceutically acceptable salt thereof.

5. The compound of claim 4 wherein

Y is CH 2 ; and

Z is O;

or a pharmaceutically acceptable salt thereof.

6. A compound of claim 1 wherein

W is O;

or a pharmaceutically acceptable salt thereof.

7. The compound of claim 1 wherein

Q is CR 8 ; and

R 8 is hydrogen;

or a pharmaceutically acceptable salt thereof.

8. The compound of claim 1 wherein

R 2 is hydrogen; and

R 3 is hydrogen;

or a pharmaceutically acceptable salt thereof.

9. The compound of claim 5 wherein

R 5 is —CO 2 H; or a pharmaceutically acceptable salt thereof.

10. The compound of claim 1 wherein R 4 is selected from:

1) C 1-3 alkyl, and

2) C 3 cycloalkyl,

wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three substituents selected from: halogen and OC 1-3 alkyl; or a pharmaceutically acceptable salt thereof.

11. The compound of claim 1 wherein R 4 is C 1-3 alkyl, wherein alkyl is unsubstituted or substituted with one to three substituents selected from: halogen or OC 1-3 alkyl; or a pharmaceutically acceptable salt thereof.

12. The compound of claim 1 wherein

R 6 is hydrogen; and

R 7 is hydrogen;

or a pharmaceutically acceptable salt thereof.

13. The compound of claim 1 wherein

R 9 is C 1-6 alkyl, and

R 10 is C 1-6 alkyl;

or a pharmaceutically acceptable salt thereof.

14. The compound of claim 1 wherein R 1 is selected from:

1) —C 3-9 cycloalkyl,

2) —C 2-8 cycloheteroalkyl,

3) aryl, and

4) heteroaryl,

wherein cycloalkyl, cycloheteroalkyl, aryl and heteroaryl are unsubstituted or substituted with one to five substituents selected from R a ; or a pharmaceutically acceptable salt thereof.

15. The compound of claim 1 wherein R 1 is selected from:

1) —C 3-9 cycloalkyl, and

2) —C 2-8 cycloheteroalkyl,

wherein cycloalkyl, and cycloheteroalkyl are unsubstituted or substituted with one to five substituents selected from R a ; or a pharmaceutically acceptable salt thereof.

16. The compound of claim 1 wherein

T is CH;

U is CH;

V is CH;

X is CH 2 ;

Y is O or CH 2 ;

Z is O or CH 2 ;

W is bond or O;

Q is CR 8 ;

R 1 is selected from:

1) —C 3-9 cycloalkyl,

2) —C 2-8 cycloheteroalkyl,

3) aryl, and

4) heteroaryl,

wherein cycloalkyl, cycloheteroalkyl, aryl and heteroaryl are unsubstituted or substituted with one to five substituents selected from R a ;

R 2 is hydrogen;

R 3 is hydrogen;

R 4 is selected from:

1) C 1-3 alkyl, and

2) C 3 cycloalkyl,

wherein alkyl and cycloalkyl are unsubstituted or substituted with one to three substituents selected from: halogen and OC 1-3 alkyl;

R 5 is —CO 2 H or tetrazole;

R 6 is hydrogen;

R 7 is hydrogen;

R 8 is hydrogen;

R 9 is C 1-6 alkyl, and

R 10 is C 1-6 alkyl;

or a pharmaceutically acceptable salt thereof.

17. The compound of claim 1 wherein

T is CH;

U is CH;

V is CH;

X is CH 2 ;

Y is CH 2 ;

Z is O;

W is O;

Q is CR 8 ;

R 1 is selected from:

1) —C 3-9 cycloalkyl,

2) —C 2-8 cycloheteroalkyl, and

3) aryl,

wherein cycloalkyl, cycloheteroalkyl, and aryl are unsubstituted or substituted with one to five substituents selected from R a ;

R 2 is hydrogen;

R 3 is hydrogen;

R 4 is C 1-3 alkyl;

R 5 is —CO 2 H;

R 6 is hydrogen;

R 7 is hydrogen;

R 8 is hydrogen;

R 9 is C 1-6 alkyl, and

R 10 is C 1-6 alkyl;

or a pharmaceutically acceptable salt thereof.

18. The compound of claim 1 wherein

T is CH;

U is CH;

V is CH;

X is CH 2 ;

Y is CH 2 ;

Z is O;

W is O;

Q is CR 8 ;

R 1 is selected from:

1) —C 3-9 cycloalkyl, and

2) —C 2-8 cycloheteroalkyl,

wherein cycloalkyl, and cycloheteroalkyl are unsubstituted or substituted with one to five substituents selected from R a ;

R 2 is hydrogen;

R 3 is hydrogen;

R 4 is C 1-3 alkyl;

R 5 is —CO 2 H;

R 6 is hydrogen;

R 7 is hydrogen;

R 8 is hydrogen;

R 9 is C 1-6 alkyl, and

R 10 is C 1-6 alkyl;

or a pharmaceutically acceptable salt thereof.

19. The compound of claim 1 which is selected from:

1) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N—((S)-pyrrolidin-3-yl)carbamimidoyl)-chroman-2-yl)propanoic acid;

2) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N—((R)-pyrrolidin-3-yl)-carbamimidoyl)-chroman-2-yl)propanoic acid;

3) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3S,5R)-5-(hydroxymethyl)-pyrrolidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

4) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3R,5R)-5-(hydroxymethyl)pyrrolidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

5) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N—((S)-azepan-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

6) (S)-2-((R)-6-(N-((1s,4S)-4-aminocyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)-amino)-2-oxo-ethylidene)amino)oxy)propanoic acid;

7) (S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid;

8) (S)-2-((R)-6-(N-((1r,3R)-3-aminocyclobutyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid;

9) (S)-2-((R)-6-(N-(3-(aminomethyl)bicyclo[1.1.1]pentan-1-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

10) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N—((R)-azepan-3-yl)carbamimidoyl)-chroman-2-yl)propanoic acid;

11) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N—((S)-azepan-3-yl)carbamimidoyl)-chroman-2-yl)propanoic acid;

12) (S)-2-((R)-6-(N-(1-(aminomethyl)-2-oxabicyclo[2.1.1]hexan-4-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

13) (S)-2-((R)-6-(N-(2-azaspiro[3.5]nonan-7-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid;

14) (S)-2-((R)-6-(N-(2-azaspiro[3.3]heptan-6-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid;

15) (S)-2-((R)-6-(N-(5-aminobicyclo[3.1.1]heptan-1-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

16) (2S)-2-((2R)-6-(N-((1S,5R)-3-azabicyclo[3.2.0]heptan-6-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

17) (S)-2-((R)-6-(N-((4R,6s)-1-azaspiro[3.3]heptan-6-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxo-ethylidene)amino)oxy)propanoic acid;

18) (S)-2-((R)-6-(N-((4S,6r)-1-azaspiro[3.3]heptan-6-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxo-ethylidene)amino)oxy)propanoic acid;

19) (S)-2-((R)-6-(N-((2s,4R)-6-azaspiro[3.5]nonan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

20) (S)-2-((R)-6-(N-((2r,4S)-6-azaspiro[3.5]nonan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

21) (S)-2-((R)-6-(N-(7-azaspiro[3.5]nonan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

22) (S)-2-((R)-6-(N-((2r,4S)-6-azaspiro[3.4]octan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

23) (S)-2-((R)-6-(N-((2s,4R)-6-azaspiro[3.4]octan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

24) (S)-2-((R)-6-(N-((1S,2R,5R,6R)-5-aminobicyclo[4.1.0]heptan-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

25) (S)-2-((R)-6-(N-((1R,2R,5S,6S)-5-aminobicyclo[4.1.0]heptan-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

26) (S)-2-((R)-6-(N-((1S,2S,5R,6R)-5-aminobicyclo[4.1.0]heptan-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

27) (S)-2-((R)-6-(N-((1R,2S,5S,6S)-5-aminobicyclo[4.1.0]heptan-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

28) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

29) (S)-2-((R)-6-(N-(1-((R)-3-amino-2-hydroxypropyl)piperidin-4-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

30) (S)-2-((R)-6-(N-(1-((S)-3-amino-2-hydroxypropyl)piperidin-4-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

31) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N—((R)-azepan-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

32) (S)-2-((R)-6-(N-((1r,4R)-4-aminocyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)propanoic acid;

33) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)-amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3R,5S)-5-(hydroxymethyl)pyrrolidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

34) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1r,4R)-4-(methylamino)cyclohexyl)-carbamimidoyl)chroman-2-yl)propanoic acid;

35) (S)-2-((R)-6-(N-(4-aminobicyclo[2.2.2]octan-1-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

36) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(azetidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

37) (S)-2-((R)-6-(N-((1R,5S,6s)-3-azabicyclo[3.1.0]hexan-6-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

38) (S)-2-((R)-6-(N-(4-(aminomethyl)phenyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

39) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N—((R)-piperidin-3-yl)carbamimidoyl)-chroman-2-yl)propanoic acid;

40) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N—((S)-piperidin-3-yl)carbamimidoyl)-chroman-2-yl)propanoic acid;

41) (S)-2-((R)-6-(N-((1s,4S)-4-(aminomethyl)cyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

42) (S)-2-((R)-6-(N-((1r,4R)-4-(aminomethyl)cyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

43) (S)-2-((R)-6-(N-((2s,4R)-6-azaspiro[3.4]octan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

44) (S)-2-((R)-6-(N-((2r,4S)-6-azaspiro[3.4]octan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

45) (S)-2-((R)-6-(N-((1R,3S)-3-aminocyclopentyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

46) (S)-2-((R)-6-(N-((1S,3R)-3-aminocyclopentyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

47) (S)-2-((R)-6-(N-((1S,3S)-3-aminocyclopentyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

48) (S)-2-((R)-6-(N-((1R,3R)-3-aminocyclopentyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid);

49) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N—((S)-3,3-dimethylpiperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

50) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N—((R)-3,3-dimethylpiperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

51) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3R,4S)-3-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

52) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3S,4R)-3-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

53) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2S,4S)-2-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

54) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2R,4R)-2-(hydroxymethyl)-piperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

55) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2R,4R)-2-methylpiperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

56) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((2S,4S)-2-methylpiperidin-4-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

57) (S)-2-((R)-6-(N-((1r,4R)-4-amino-4-methylcyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

58) (S)-2-((R)-6-(N-((1s,4S)-4-amino-4-methylcyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

59) (S)-2-((R)-6-(N-((1s,4S)-4-(aminomethyl)-4-hydroxycyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

60) (S)-2-((R)-6-(N-((1r,4R)-4-(aminomethyl)-4-hydroxycyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

61) (S)-2-((R)-6-(N-((2R,4r,6R)-6-aminospiro[3.3]heptan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

62) (S)-2-((R)-6-(N-((2S,4s,6S)-6-aminospiro[3.3]heptan-2-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

63) (S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(2-methoxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

64) (S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(2-methoxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

65) (S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(2-hydroxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

66) (S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(2-hydroxyethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

67) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(trans-3-(methylamino)cyclobutyl)-carbamimidoyl)chroman-2-yl)propanoic acid;

68) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-(cis-3-(methylamino)cyclobutyl)-carbamimidoyl)chroman-2-yl)propanoic acid;

69) (S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(hydroxymethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

70) (S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(hydroxymethyl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

71) (S)-2-((R)-6-(N-((1r,4R)-4-amino-1-methylcyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

72) (S)-2-((R)-6-(N-((1s,4S)-4-amino-1-methylcyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

73) (S)-2-((R)-6-(N-((1s,4S)-4-(aminomethyl)-4-methoxycyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

74) (S)-2-((R)-6-(N-((1r,3R)-3-amino-3-methylcyclobutyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

75) (S)-2-((R)-6-(N-((1s,3S)-3-amino-3-methylcyclobutyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

76) (S)-2-((R)-6-(N-((1R,5S,8s)-3-azabicyclo[3.2.1]octan-8-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

77) (S)-2-((R)-6-(N-((1R,5S,8r)-3-azabicyclo[3.2.1]octan-8-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

78) (S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-(hydroxymethyl)cyclobutyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)-oxy)propanoic acid;

79) (S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-(hydroxymethyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

80) (S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-hydroxycyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

81) (S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-hydroxycyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

82) (S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-methoxycyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

83) (S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-methoxycyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

84) (S)-2-((R)-6-(N-((1r,3R)-3-amino-1-methylcyclobutyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

85) (S)-2-((R)-6-(N-((1s,3S)-3-amino-1-methylcyclobutyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

86) (S)-2-((R)-6-(N-((1s,3S)-3-amino-3-(2-hydroxyethyl)cyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

87) (S)-2-((R)-6-(N-((1r,3R)-3-amino-3-(2-hydroxyethyl)cyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

88) (S)-2-((R)-6-(N-((1r,3R)-3-amino-3-(hydroxymethyl)cyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

89) (S)-2-((R)-6-(N-((1s,3S)-3-amino-3-(hydroxymethyl)cyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

90) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1r,3R)-3-(hydroxymethyl)-3-(methylamino)cyclobutyl)carbamimidoyl)chroman-2-yl)propanoic acid;

91) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1s,3S)-3-(hydroxymethyl)-3-(methylamino)cyclobutyl)carbamimidoyl)chroman-2-yl)propanoic acid;

92) (S)-2-((R)-6-(N-((1r,3R)-3-amino-3-(2-methoxyethyl)cyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

93) (S)-2-((R)-6-(N-((1s,3S)-3-amino-3-(2-methoxyethyl)cyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

94) (S)-2-((R)-6-(N-((1S,3R)-3-amino-3-((S)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

95) (S)-2-((R)-6-(N-((1R,3R)-3-amino-3-((R)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

96) (S)-2-((R)-6-(N-((1R,3S)-3-amino-3-((S)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

97) (S)-2-((R)-6-(N-((1S,3S)-3-amino-3-((R)-2,3-dihydroxypropyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

98) (S)-2-((R)-6-(N-((1S,3R)-3-amino-3-((S)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

99) (S)-2-((R)-6-(N-((1R,3R)-3-amino-3-((R)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

100) (S)-2-((R)-6-(N-((1S,3S)-3-amino-3-((R)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

101) (S)-2-((R)-6-(N-((1R,3S)-3-amino-3-((S)-1,2-dihydroxyethyl)cyclobutyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

102) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1s,4S)-4-((methylamino)methyl)-cyclohexyl)carbamimidoyl)chroman-2-yl)propanoic acid;

103) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((1r,4R)-4-((methylamino)methyl)cyclohexyl)carbamimidoyl)chroman-2-yl)propanoic acid;

104) (S)-2-((R)-6-(N-((1R,4S)-4-aminocycloheptyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

105) (S)-2-((R)-6-(N-((1R,4R)-4-aminocycloheptyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxo-ethylidene)amino)oxy)propanoic acid;

106) (S)-2-((R)-6-(N-((1S,4S)-4-aminocycloheptyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxo-ethylidene)amino)oxy)propanoic acid;

107) (S)-2-((R)-6-(N-((1S,4R)-4-aminocycloheptyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

108) (S)-2-((R)-6-(N-((1R,3R)-3-aminocyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

109) (S)-2-((R)-6-(N-((1S,3S)-3-aminocyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

110) (S)-2-((R)-6-(N-((1R,3S)-3-aminocyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

111) (S)-2-((R)-6-(N-((1S,3R)-3-aminocyclohexyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

112) (S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)cyclobutyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

113) (S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)cyclobutyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

114) (S)-2-((R)-6-(N-((1S,3S)-3-amino-2,2-dimethylcyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

115) (S)-2-((R)-6-(N-((2S,4s,7S)-2-aminospiro[3.5]nonan-7-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

116) (S)-2-((R)-6-(N-((2R,4r,7R)-2-aminospiro[3.5]nonan-7-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

117) (S)-2-((R)-6-(N-((1s,3S)-3-(aminomethyl)-3-methylcyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

118) (S)-2-((R)-6-(N-((1r,3R)-3-(aminomethyl)-3-methylcyclobutyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

119) (S)-2-((R)-6-(N-(6-(aminomethyl)-6-fluorospiro[3.3]heptan-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

120) (S)-2-((R)-6-(N-((1R,3S)-3-(aminomethyl)-2,2-dimethylcyclobutyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

121) (2S)-2-((2R)-6-(N-(6-(aminomethyl)spiro[3.3]heptan-2-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

122) (2S)-2-((2R)-6-(N-((1S)-1-aminospiro[2.3]hexan-5-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

123) (2S)-2-((2R)-6-(N-((1R)-1-aminospiro[2.3]hexan-5-yl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

124) (S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)carbamimidoyl)-5-(methoxymethyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

125) (S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)carbamimidoyl)-7-(methoxymethyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

126) (S)-2-((R)-6-(N-((1s,4S)-4-amino-1-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

127) (S)-2-((R)-6-(N-((1r,4R)-4-amino-1-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

128) (S)-2-((R)-6-(N-((1s,4S)-4-amino-4-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

129) (S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(methoxymethyl)cyclohexyl)-carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

130) (S)-2-((R)-6-(N-((1s,4S)-4-(aminomethyl)-1-methylcyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

131) (S)-2-((R)-6-(N-((1r,4R)-4-(aminomethyl)-1-methylcyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

132) (S)-2-((R)-6-(N-((1s,4S)-4-(2-aminopropan-2-yl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

133) (S)-2-((R)-6-(N-((1r,4R)-4-(2-aminopropan-2-yl)cyclohexyl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

134) (S)-2-((R)-6-(N-((1s,3S)-3-aminocyclobutyl)carbamimidoyl)-7-methylchroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

135) (S)-2-((R)-6-(N-((1r,4R)-4-amino-4-(hydroxymethyl)-1-methylcyclohexyl)-carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

136) (S)-2-((R)-6-(N-((1R,3r,5S)-8-azabicyclo[3.2.1]octan-3-yl)carbamimidoyl)-chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

137) (S)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)-azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)-2-((R)-6-(N-((3S,5S)-5-(hydroxymethyl)pyrrolidin-3-yl)carbamimidoyl)chroman-2-yl)propanoic acid;

138) (S)-2-((R)-6-(N-(1-(2-aminoethyl)cyclopropyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

139) (S)-2-((R)-6-(N-(1-(3-aminopropyl)cyclopropyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid; and

140) (S)-2-((R)-6-(N-(1-(2-aminoethyl)cyclobutyl)carbamimidoyl)chroman-2-yl)-2-((((Z)-1-(2-aminothiazol-4-yl)-2-(((S)-2,2-dimethyl-4-oxo-1-(sulfooxy)azetidin-3-yl)amino)-2-oxoethylidene)amino)oxy)propanoic acid;

or a pharmaceutically acceptable salt thereof.

20. The compound of claim 1 which is selected from:

or a pharmaceutically acceptable salt thereof.

21. A pharmaceutical composition comprising a therapeutically effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

22. A pharmaceutical composition according to claim 21 , which further comprises a therapeutically effective amount of a beta-lactamase inhibitor compound.

23. A pharmaceutical composition according to claim 22 wherein the beta-lactamase inhibitor compound is selected from relebactam, tazobactam, clavulanic acid, sulbactam, avibactam, taniborbactam, nacubactam, vaborbactam, zidebactam, and durlobactam.

24. A method for treating a bacterial infection which comprises administering to a subject in need of such treatment a therapeutically effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof.

25. The method of claim 24 further comprising administering to a subject in need of such treatment a therapeutically effective amount of a beta-lactamase inhibitor compound.

26. The method of claim 25 wherein the beta-lactamase inhibitor compound is selected from relebactam, tazobactam, clavulanic acid, sulbactam, avibactam, taniborbactam, nacubactam, vaborbactam, zidebactam, and durlobactam.

27. The method of claim 24 wherein the bacterial infection is due to Pseudomonas spp., Klebsiella spp., Enterobacter spp., Escherichia spp., Morganella spp., Citrobacter spp., Serratia spp. or Acintetobacter spp.

28. A compound which is

or a pharmaceutically acceptable salt thereof.

29. A compound which is

or a pharmaceutically acceptable salt thereof.

30. A compound which is

or a pharmaceutically acceptable salt thereof.

31. A compound which is

or a pharmaceutically acceptable salt thereof.

32. A compound which is

or a pharmaceutically acceptable salt thereof.

33. A compound which is

or a pharmaceutically acceptable salt thereof.

34. A compound which is

or a pharmaceutically acceptable salt thereof.

35. A compound which is

or a pharmaceutically acceptable salt thereof.

36. A compound which is

or a pharmaceutically acceptable salt thereof.

37. A compound which is

or a pharmaceutically acceptable salt thereof.

38. A compound which is

or a pharmaceutically acceptable salt thereof.

39. A compound which is

40. A compound which is

41. A compound which is

42. A compound which is

43. A compound which is

44. A compound which is

45. A compound which is

46. A compound which is

47. A compound which is

48. A compound which is

49. A compound which is