Peptide deformylase inhibitors

1. A compound according to Formula (I):

wherein:

R1 is —N(OH)—CHO;

R2 is selected from:

1) C 1 -C 6 -alkyl,

2) C 3 -C 7 -cycloalkyl,

3) aryl, or

4) heteroaryl,

wherein:

C 1 -C 6 -alkyl is optionally substituted by one to three R6 groups;

each C 3 -C 7 -cycloalkyl, aryl, and heteroaryl as defined above optionally are substituted by one to three R7 groups;

R3 and R4 are joined together to form a pyrrolidinyl ring or a pyrrolidinyl ring optionally substituted with one or two C1-C3 alkyl groups;

1) —C(O)R8,

2) —C(O)OR8, or

3) —C(O)NR8R9;

wherein:

R6 as defined above independently is selected from:

1) OH,

2) CF 3 ,

3) —NR9R9,

4) cyano,

5) OC 1 -C 3 -alkyl,

6) phenyl,

7) heteroaryl,

8) heterocycloalkyl,

9) —NHC(O)OC 1 -C 6 -alkyl, or

10) —NHCOH;

R7 as defined above independently is selected from:

1) OH,

2) halo,

3) cyano,

4) nitro,

5) —NR9R9,

6) CF 3 ,

7) —NHC(O)CH 3 ,

8) —OCH 3 ,

9) C 1 -C 6 -alkyl,

10) heteroaryl, or

11) heterocycloalkyl;

R8 as defined above independently is selected from:

1) C 1 -C 6 -alkyl,

2) C 2 -C 6 -alkenyl,

3) C 3 -C 7 -cycloalkyl,

4) phenyl,

5) heteroaryl or

6) heterocycloalkyl,

wherein:

C 1 -C 6 -alkyl is optionally substituted by one to three R6 groups;

C 3 -C 7 -cycloalkyl, phenyl, and heteroaryl are each optionally substituted by one to three R7 groups; or

heterocycloalkyl is optionally substituted by one to three R10 groups;

each R9 as defined above independently is selected from:

1) H or

2) C 1 -C 6 -alkyl;

R10 as defined above independently is selected from

1) OH,

2) C 1 -C 6 -alkyl,

3) phenyl,

4) NH 2 ;

5) —C(O)OC 1 -C 6 -alkyl; or

a pharmaceutically acceptable salt thereof.

2. A compound according to claim 1 wherein:

R6 independently is selected from:

1) OH,

2) CF 3 ,

3) —NR9R9,

4) cyano,

5) —OCH 3 ,

6) phenyl, and

7) heteroaryl;

R10 independently is selected from

1) OH,

2) C 1 -C 6 -alkyl,

3) phenyl, or

4) NH 2 ;

or a pharmaceutically acceptable salt thereof.

3. A compound according to claim 1 , wherein R2 is unsubstituted C 1 -C 6 -alkyl or C 3 -C 7 -cycloalkyl.

4. A compound according to claim 1 , wherein R2 is unsubstituted n-butyl or cyclopentyl; or a pharmaceutically acceptable salt thereof.

5. A compound according to claim 1 , wherein R3 and R4 are joined together to form 3,3-dimethyl-pyrrolidinyl ring; or a pharmaceutically acceptable salt thereof.

6. A compound which is:

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(4-fluorophenyl)carbonyl]-L-prolinamide;

N-acetyl-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-(phenylcarbonyl)-L-prolinamide;

N-{[4-(acetylamino)phenyl]carbonyl}-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(methyloxy)acetyl]-L-prolinamide;

N-[1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolyl]-6-(trifluoromethyl)-3-pyridinecarboxamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[1,5-dimethyl-1H-pyrazol-3-yl)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(1,3-dimethyl-1H-pyrazol-5-yl)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(5-methyl-3-isoxazolyl)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(2-fluorophenyl)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(3-fluorophenyl)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(3-fluoro-4-methylphenyl)carbonyl]-L-prolinamide;

N-[1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolyl]-4-morpholinecarboxamide;

N-[(3-cyanophenyl)carbonyl]-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(2,5-difluorophenyl)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(methyloxy)carbonyl]-L-prolinamide;

N-[1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolyl]-4-pyridinecarboxamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(2,6-difluorophenyl)carbonyl]-L-prolinamide;

N-{[(trans-4-aminocyclohexyl)oxy]carbonyl}-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

N-[1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolyl]-6-(4-morpholinyl)-3-pyridinecarboxamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[4-(1H-pyrazol-1-yl)phenyl]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(phenylmethyl)oxy]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(ethyloxy)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(tetrahydro-2H-pyran-4-yloxy)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(cyclopentyloxy)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[4-(1H-imidazol-1-yl)phenyl]carbonyl}-L-prolinamide;

N-[(cyclohexyloxy)carbonyl]-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-(2-thienylcarbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(2-propen-1-yloxy)carbonyl]-L-prolinamide;

2,3-dihydro[1,4]dioxino[2,3-c]pyridin-7-ylmethyl[1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolyl]carbamate;

N-[(cyclobutyloxy)carbonyl]-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(1,1-dimethylethyl)oxy]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[trans-4-(dimethylamino)cyclohexyl]oxy}carbonyl)-L-prolinamide;

N-{[(trans-3-aminocyclobutyl)oxy]carbonyl}-1-((2R)-3-cyclopentyl-2-{[formyl (hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[4-(4-ethyl-1-piperazinyl)phenyl]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-(2,2-dimethylpropanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(1-methylethyl)oxy]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(1-methyl-3-pyrrolidinyl)oxy]carbonyl}-L-prolinamide (mixture of diastereomers);

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(3R)-tetrahydro-3-furanyloxy]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(3S)-tetrahydro-3-furanyloxy]carbonyl}-L-prolinamide;

1-methyl-3-piperidinyl[1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolyl]carbamate (mixture of diastereomers);

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[1-(1-methylethyl)-3-pyrrolidinyl]oxy}carbonyl)-L-prolinamide (mixture of diastereomers);

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-(4-isoxazolylcarbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(tetrahydro-2H-thiopyran-4-yloxy)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(1,1-dioxidotetrahydro-2H-thiopyran-4-yl)oxy]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[(1S)-1-methyl-2-(methyloxy)ethyl]oxy}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[(1R)-1-methyl-2-(methyloxy)ethyl]oxy}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[4-(1-piperazinyl)phenyl]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-(2-methylpropanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-(3-methylbutanoyl)-L-prolinamide;

N-[1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolyl]-2-pyridinecarboxamide;

N-[1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolyl]-3-pyridinecarboxamide;

N-(cyclobutylcarbonyl)-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{(ethylamino)carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-(cyclopropylcarbonyl)-L-prolinamide;

N-(cyclopentylacetyl)-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

N-(cyclopentylcarbonyl)-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

N-(cyclohexylcarbonyl)-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1,1-dimethylethyl 3-({[1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolyl]amino}carbonyl)-1-pyrrolidinecarboxylate (mixture of diastereomers);

N-(cyclopentylcarbonyl)-1-((2R)-2-{[formyl(hydroxy)amino]methyl}heptanoyl)-L-prolinamide;

N-(2,2-dimethylpropanoyl)-1-((2R)-2-{[formyl(hydroxy)amino]methyl}heptanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[(methyloxy)carbonyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(1,1-dimethylethyl)amino]carbonyl}-L-prolinamide;

N-{[(1,1-dimethylethyl)oxy]carbonyl}-1-((2R)-2-{[formyl(hydroxy)amino]methyl}heptanoyl)-L-prolinamide;

N-[(ethylamino)carbonyl]-1-((2R)-2-{[formyl(hydroxy)amino]methyl}heptanoyl)-L-prolinamide;

N 1 -(cyclopentylcarbonyl)-N 2 -((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3-methyl-L-valinamide;

N 2 -((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N 1 -(2,2-dimethylpropanoyl)-3-methyl-L-valinamide;

N 2 -((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N 1 -{[(1,1-dimethylethyl)oxy]carbonyl}-3-methyl-L-valinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(1-methylethyl)amino]carbonyl}-L-prolinamide;

N-[(cyclopentylamino)carbonyl]-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

N-[(butylamino)carbonyl]-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

N 2 -((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N 1 -[(ethylamino)carbonyl]-3-methyl-L-valinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[4-(methyloxy)phenyl]amino}carbonyl)-L-prolinamide;

N-[(cyclohexylamino)carbonyl]-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

N 2 -((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3-methyl-N 1 -[(methyloxy)carbonyl]-L-valinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(propylamino)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(2-propen-1-ylamino)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(dimethylamino)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(phenylmethyl)amino]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-N-[(methyloxy)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(2-phenylethyl)amino]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(methylamino)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(4-phenylbutyl)amino]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[(2S)-2-hydroxypropyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[(2R)-2-hydroxypropyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-(3-pyridinyl)ethyl]amino}carbonyl)-L-prolinamide hydrochloride;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(3-phenylpropyl)amino]carbonyl}-L-prolinamide;

N-({[2-(1-benzofuran-2-yl)ethyl]amino}carbonyl)-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-(3,5-dimethyl-1H-pyrazol-4-yl)ethyl]amino}carbonyl)-L-prolinamide;

ethyl 4-[({[1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolyl]amino}carbonyl)amino]-1-piperidinecarboxylate;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-(2-pyridinyl)ethyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-(2-pyrazinyl)ethyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-(4-pyridinyl)ethyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(4-hydroxybutyl)amino]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(5-hydroxypentyl)amino]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[3-(dimethylamino)propyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-[5-(methyloxy)-1H-indol-3-yl]ethyl}amino]carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[3-(2-oxo-1-pyrrolidinyl)propyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[(1-methyl-1H-imidazol-2-yl)methyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[(1,5-dimethyl-1H-pyrazol-4-yl)methyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[3-(4-morpholinyl)propyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(2-phenylpropyl)amino]carbonyl}-L-prolinamide (mixture of diastereomers);

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-(1-piperidinyl)ethyl]amino}carbonyl)-L-prolinamide formate;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(2-hydroxyethyl)amino]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-(1-pyrrolidinyl)ethyl]amino}carbonyl)-L-prolinamide formate;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[{3-[(1-methylethyl)oxy]propyl}amino)carbonyl]-L-prolinamide;

N-({[2-(4-aminophenyl)ethyl]amino}carbonyl)-1-((2R)-3-cyclopentyl-2-{[formyl (hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(3-hydroxypropyl)amino]carbonyl}-L-prolinamide;

N-(aminocarbonyl)-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(cyclopropylamino)carbonyl]-3,3-dimethyl-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-N-{[(3R)-tetrahydro-3-furanyloxy]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(tetrahydro-2-furanylmethyl)amino]carbonyl}-L-prolinamide (mixture of diastereomers);

N-[(cyclobutylamino)carbonyl]-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

N-({[2-(6-amino-5-fluoro-3-pyridinyl)ethyl]amino}carbonyl)-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-N-{[(2-oxetanylmethyl)oxy]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(ethylamino)carbonyl]-3,3-dimethyl-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(cyclopropylamino)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-N-[(methylamino)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-N-({[(3-methyl-3-oxetanyl)methyl]oxy}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-N-[(3-oxetanyloxy)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(3S)-tetrahydro-3-furanylamino]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(3-methylbutyl)amino]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-(4-pyridazinyl)ethyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-N-({[(1S)-1-methyl-2-(methyloxy)ethyl]oxy}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-N-({[(1R)-1-methyl-2-(methyloxy)ethyl]oxy}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-N-[(tetrahydro-2H-pyran-4-yloxy)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-(methyloxy)ethyl]amino}carbonyl)-L-prolinamide;

N-(aminocarbonyl)-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

N-{[(trans-3-cyanocyclobutyl)amino]carbonyl}-1-((2R)-3-cyclopentyl-2-{[formyl (hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(1-hydroxy-1,2,3,4-tetrahydro-2-naphthalenyl)amino]carbonyl}-L-prolinamide (mixture of trans-diastereomers);

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-N-{[(3S)-tetrahydro-3-furanyloxy]carbonyl}-L-prolinamide;

N-({[2-(6-amino-5-chloro-3-pyridinyl)ethyl]amino}carbonyl)-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(2,3-dihydro-1,4-benzodioxin-2-ylmethyl)amino]carbonyl}-L-prolinamide (mixture of diastereomers);

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(2-imidazo[1,2-a]pyridin-6-ylethyl)amino]carbonyl}-L-prolinamide formate;

N-[(cyclobutyloxy)carbonyl]-1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-3,3-dimethyl-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[(2S)-2-hydroxy-2-phenylethyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[(2R)-2-hydroxy-2-phenylethyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(5-methyl-1H-pyrazol-3-yl)amino]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[(2,3-dihydro-1H-inden-2-ylamino)carbonyl]-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-(1H-pyrazol-1-yl)ethyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[2-(diethylamino)ethyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-{[(2-fluoroethyl)amino]carbonyl}-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[3-(diethylamino)propyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[3-(methyloxy)propyl]amino}carbonyl)-L-prolinamide;

N-({[3,3-bis(ethyloxy)propyl]amino}carbonyl)-1-((2R)-3-cyclopentyl-2-{[formyl (hydroxy)amino]methyl}propanoyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-({[3-({[(1,1-dimethylethyl)oxy]carbonyl}amino)propyl]amino}carbonyl)-L-prolinamide;

1-((2R)-3-cyclopentyl-2-{[formyl(hydroxy)amino]methyl}propanoyl)-N-[({2-[4-(formylamino)phenyl]ethyl}amino)carbonyl]-L-prolinamide; or

a pharmaceutically acceptable salt thereof.

7. A method of treating a bacterial infection which comprises administering a compound according to claim 1 , or a pharmaceutically acceptable salt thereof to a subject in need thereof.

8. A pharmaceutical composition comprising a compound according to claim 1 , or a pharmaceutically acceptable salt thereof, and one or more pharmaceutically acceptable excipients.