N-hydroxyamide derivatives and use thereof

1. A N-hydroxyamide according to Formula (I),

wherein:

A is N;

R 1 is selected from C 1 -C 6 alkyl, C 3 -C 8 -cycloalkyl, aryl, pyridinyl, pyrazinyl, thiadiazolyl, pyrimidinyl, oxadiazolyl, quinolinyl, thienyl, benzofuranyl, amino and alkoxy;

R 2 is selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 3 -C 8 -cycloalkyl, and aryl;

R 3 is selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl and C 2 -C 6 alkynyl;

R 4 , R 5 , R 6 and R 7 are independently selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl; or R 4 and R 7 form together a —CH 2 — linkage;

n is an integer selected from 1, 2, 3, 4, 5 and 6;

wherein R 1 -R 7 may be substituted by from 1 to 5 substituents selected from the group consisting of C 1 -C 6 -alkyl, amino, halogen, carboxy, trihalomethyl, cyano, hydroxy, mercapto, and nitro;

Carbons (2) and (3) are two chiral centers, wherein chiral center (2) has a configuration selected from “S” and “R” and wherein chiral center (3) has a “S” configuration as well as pharmaceutically acceptable salts thereof.

2. A N-hydroxyamide according to claim 1 having a Formula (Ia):

wherein A is N;

R 1 is selected from C 1 -C 6 alkyl, C 3 -C 8 -cycloalkyl, aryl, pyridinyl, pyrazinyl, thiadiazolyl, pyrimidinyl, oxadiazolyl, quinolinyl, thienyl, benzofuranyl, amino and alkoxy;

R 2 is selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 3 -C 8 -cycloalkyl, and aryl;

R 3 is selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl and C 2 -C 6 alkynyl;

R 4 , R 5 , R 6 and R 7 are independently selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl; or R 4 and R 7 form together a —CH 2 — linkage;

n is an integer selected from 1, 2, 3, 4, 5 and 6;

Carbons (2) and (3) are two chiral centers, wherein chiral center (2) has a configuration selected from “S” and “R” and wherein chiral center (3) has a “S” configuration as well as pharmaceutically acceptable salts thereof.

3. A N-hydroxyamide according to claim 1 wherein R 1 is selected from aryl, pyridinyl, pyrazinyl, thiadiazolyl, pyrimidinyl, oxadiazolyl, quinolinyl, thienyl, and benzofuranyl.

4. A N-hydroxyamide according to claim 1 wherein R 2 is selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl and C 2 -C 6 alkynyl.

5. A N-hydroxyamide according to claim 1 wherein R 2 is aryl.

6. A N-hydroxyamide according to claim 1 wherein R 2 is optionally substituted C 3 -C 8 -cycloalkyl.

7. A N-hydroxyamide according to claim 1 wherein R 3 is H.

8. A N-hydroxyamide according to claim 1 wherein R 4 , R 5 and R 7 are H.

9. A N-hydroxyamide according to claim 1 wherein R 6 is selected from H and C 1 -C 6 alkyl.

10. A N-hydroxyamide according to claim 1 wherein R 5 and R 6 are H and R 4 and R 7 can form together a —CH 2 — linkage.

11. A N-hydroxyamide according to claim 1 wherein the configuration of the chiral carbons is (2S), (3S).

12. A N-hydroxyamide according to claim 1 wherein the configuration of the chiral carbons is (2R), (3S).

13. A N-hydroxyamide according to claim 1 wherein R 1 is aryl; R 2 is selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, and C 3 -C 8 -cycloalkyl; R 3 , R 4 , R 5 and R 7 are H; R 6 is selected from H and methyl; A is N; and n is an integer selected from 1, 2 and 3.

14. A N-hydroxyamide according to claim 1 wherein R 1 is selected from aryl, pyridinyl, pyrazinyl, thiadiazolyl, pyrimidinyl, oxadiazolyl, quinolinyl, thienyl, and benzofuranyl; R 2 is aryl; R 3 , R 4 , R 5 and R 7 are H; R 6 is selected from H and methyl; A is N; and n is an integer selected from 1, 2 and 3.

15. A N-hydroxyamide compound selected from the group consisting of:

(2S,3S)-N,2-dihydroxy-5-methyl-3-{[4-(3-phenyl-1,2,4-thiadiazol-5-yl)-1-piperazinyl]carbonyl}hexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-({(2R)-2-methyl-4-[4-(trifluoromethyl)pyridin-2-yl]piperazin-1-yl}carbonyl)hexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-{[(2R)-2-methyl-4-(2-pyridinyl)piperazinyl]carbonyl}hexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-{[(2S)-2-methyl-4-pyridin-2-ylpiperazin-1-yl]carbonyl}hexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-{[(2R)-2-methyl-4-pyrimidin-2-ylpiperazin-1-yl]carbonyl}hexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-{[(2S)-2-methyl-4-(4-methylpyridin-2-yl)piperazin-1-yl]carbonyl}hexanamide;

(2S,3S)-3-{[(2R)-4-(2-fluoro-5-methoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(2-fluorophenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2R,3S)-N,2-dihydroxy-3-{[4-(4-methoxyphenyl)piperazin-1-yl]carbonyl}-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(4-chloro-2-fluorophenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(5-chloropyridin-2-yl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2R,3S)-3-{[4-(4-fluorophenyl)piperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2R,3S)-3-{[(1S,4S)-5-(4-fluorophenyl)-2,5-diazabicyclo[2.2.1]hept-2-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2R,3S)-N,2-dihydroxy-5-methyl-3-[(4-pyridin-2-ylpiperazin-1-yl)carbonyl]hexanamide;

(2R,3S)-N,2-dihydroxy-5-methyl-3-({4-[4-(trifluoromethyl)phenyl]piperazin-1-yl}carbonyl)hexanamide;

(2R,3S)-3-{[4-(2-fluorophenyl)piperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2R,3S)-N,2-dihydroxy-5-methyl-3-[(4-pyrimidin-2-ylpiperazin-1-yl)carbonyl]hexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-({(2R)-2-methyl-4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}carbonyl)hexanamide;

(2S,3S)-3-{[(2R)-4-biphenyl-4-yl-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2S)-4-(2-fluorophenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(3-chlorophenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2R,3S)-N,2-dihydroxy-5-methyl-3-{[4-(5-phenyl-1,2,4-oxadiazol-3-yl)piperazin-1-yl]carbonyl}hexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-{[(2R)-2-methyl-4-(5-phenylpyridin-2-yl)piperazin-1-yl]carbonyl}hexanamide;

3-[(4-biphenyl-4-ylpiperazin-1-yl)carbonyl]-3,4-dideoxy-1-(hydroxyamino)-5-O-(phenylmethyl)-L-threo-pentose;

(2R,3S)-N,2-dihydroxy-5-methyl-3-{[4-(5-pyridin-4-yl-1,2,4-oxadiazol-3-yl)piperazin-1-yl]carbonyl}hexanamide;

(2S,3S)-3-{[4-(2-fluorophenyl)piperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2R,3S)-N,2-dihydroxy-5-methyl-3-({4-[5-(2-thienyl)-1,2,4-oxadiazol-3-yl]piperazin-1-yl}carbonyl)hexanamide;

(2R,3S)-3-{[(2R)-4-(5-chloropyridin-2-yl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2R,3S)-3-{[4-(5-chloropyridin-2-yl)piperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2R,3S)-3-{[4-(5-bromopyridin-2-yl)piperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(4-chlorophenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-({(2R)-2-methyl-4-[5-(trifluoromethyl)pyridin-2-yl]piperazin-1-yl}carbonyl)hexanamide;

(2R,3S)-3-benzyl-N,2-dihydroxy-4-oxo-4-{4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}butanamide;

(2S,3S)-3-benzyl-N,2-dihydroxy-4-{(2R)-2-methyl-4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}-4-oxobutanamide;

(2R,3S)-N,2-dihydroxy-3-methyl-4-oxo-4-{4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}butanamide;

(2S)-N,2-dihydroxy-3-methyl-4-{(2R)-2-methyl-4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}-4-oxobutanamide;

(2S,3S)-3-{[(2R)-4-(4′-fluorobiphenyl-4-yl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(4-ethoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(3,4-dimethoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-({(2R)-2-methyl-4-[4-(methylsulfonyl)phenyl]piperazin-1-yl}carbonyl)hexanamide;

(2S,3S)-N,2-dihydroxy-3-{[(2R)-4-(6-methoxy-2-naphthyl)-2-methylpiperazin-1-yl]carbonyl}-5-methylhexanamide;

(2S,3S)-3-({(2R)-4-[4-(1-benzofuran-3-yl)phenyl]-2-methylpiperazin-1-yl}carbonyl)-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-{[(2R)-2-methyl-4-(4-propoxyphenyl)piperazin-1-yl]carbonyl}hexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-({(2R)-2-methyl-4-[4-(trifluoromethyl)phenyl]piperazin-1-yl}carbonyl)hexanamide;

(2S,3S)-3-{[(2R)-4-(4-tert-butylphenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(5-fluoropyrimidin-2-yl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-{[(2R)-2-methyl-4-(4-propylphenyl)piperazin-1-yl]carbonyl}hexanamide;

(2S,3S)-3-(cyclopentylmethyl)-N,2-dihydroxy-4-{(2R)-2-methyl-4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}-4-oxobutanamide;

(2S,3S)-3-{[(2R)-4-(2,3-dihydro-1-benzofuran-5-yl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(1,3-benzodioxol-5-yl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-3-{[(2R)-4-(4-methoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-[((2R)-2-methyl-4-{4-[(trifluoromethyl)sulfonyl]phenyl}piperazin-1-yl)carbonyl]hexanamide;

(2S,3S)-N,2-dihydroxy-3-{[(2R)-4-(4′-methoxybiphenyl-4-yl)-2-methylpiperazin-1-yl]carbonyl}-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(4-cyclohexylphenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(1-benzofuran-5-yl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(2,2-difluoro-1,3-benzodioxol-5-yl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(3-fluoro-4-methoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(3-fluoro-4-isopropoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-3-({(2R)-4-[3-fluoro-4-(trifluoromethoxy)phenyl]-2-methylpiperazin-1-yl}carbonyl)-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-{[(2R)-2-methyl-4-quinolin-3-ylpiperazin-1-yl]carbonyl}hexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-{[(2R)-2-methyl-4-(4-methylphenyl)piperazin-1-yl]carbonyl}hexanamide;

(2S,3S)-3-{[(2R)-4-(5-chloro-2-thienyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-3-{[(2R)-4-(3-methoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-5-methylhexanamide;

(2S,3S)-3-{[(2R)-4-(4′-bromobiphenyl-4-yl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-({(2R)-2-methyl-4-[4-(2,2,2-trifluoroethoxy)phenyl]piperazin-1-yl}carbonyl)hexanamide;

(2S,3S)-3-{[(2R)-4-(4-tert-butoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-3-{[(2R)-4-(4-isopropoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-{[(2R)-2-methyl-4-quinolin-6-ylpiperazin-1-yl]carbonyl}hexanamide;

(2S,3S)-3-({(2R)-4-[3,5-bis(trifluoromethyl)phenyl]-2-methylpiperazin-1-yl}carbonyl)-N,2-dihydroxy-5-methylhexanamide;

(2S,3S)-N,2-dihydroxy-5-methyl-3-({(2R)-2-methyl-4-[4-(1,3-oxazol-5-yl)phenyl]piperazin-1-yl}carbonyl)hexanamide; and

(2S,3S)-3-({(2R)-4-[4-(dimethylamino)phenyl]-2-methylpiperazin-1-yl}carbonyl)-N,2-dihydroxy-5-methylhexanamide.

16. A pharmaceutical composition comprising at least one N-hydroxyamide according to claim 1 , and a pharmaceutically acceptable carrier, diluent or excipient thereof.

17. A process for the preparation of a N-hydroxyamide, according to claim 1 , comprising reacting a compound of Formula (IV) with a derivative H 2 N—O—R 8 :

wherein A, R 1 , R 2 , R 4 , R 5 , R 6 , R 7 and n are as defined in claim 1 and R 8 is selected from H and a protective group selected from t-butyl, benzyl, trialkylsilyl, tetrahydropyranyl.

18. A process for the preparation of a N-hydroxyamide, according to claim 1 , comprising reacting a compound of Formula (V) with a derivative H 2 N—O—R 8 :

wherein A, R 1 , R 2 , R 4 , R 5 , R 6 , R 7 and n are as defined in claim 1 and R 8 is selected from H and a protective group.

19. A process according to claims 17 , wherein R 8 is a protective group and the process further comprises deprotecting the compound of formula (I) by removing the protective group.

20. A process for the preparation of a N-hydroxyamide, according to claim 1 , comprising reacting a compound of Formula (II) with an amine of Formula (III) to form a compound of Formula (IV), optionally in presence of a coupling agent selected from DIC, EDC, TBTU, DCC, HATU, PyBOP®, Isobutyl chloroformate and 1-methyl-2-chloropyridinium iodide; and reacting the compound of formula (IV) with hydroxylamine or a protected hydroxylamine and, if protected hydroxylamine, removing the protecting group to form a compound of formula (I)

wherein A, R 1 , R 2 , R 4 , R 5 , R 6 , R 7 and n are as defined in claim 1 ; G is a group selected from OH and Cl.

21. A compound according to Formula (IV):

wherein A is N;

R 1 is selected from C 1 -C 6 alkyl, C 3 -C 8 -cycloalkyl, aryl, pyridinyl, pyrazinyl, thiadiazolyl, pyrimidinyl, oxadiazolyl, quinolinyl, thienyl, benzofuranyl, amino and alkoxy;

R 2 is selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 3 -C 8 -cycloalkyl, and aryl;

R 4 , R 5 , R 6 and R 7 are independently selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl; or R 4 and R 7 form together a —CH 2 — linkage;

n is an integer selected from 1, 2, 3, 4, 5 and 6;

wherein R 1 , R 2 , R 4 , R 5 , R 6 and R 7 may be substituted by from 1 to 5 substituents selected from the group consisting of C i -C 6 -alkyl, amino, halogen, carboxy, trihalomethyl, cyano, hydroxy, mercapto, and nitro;

Carbons (2) and (3) are two chiral centers, wherein chiral center (2) has a configuration selected from “S” and “R” and wherein chiral center (3) has a “S” configuration as well as pharmaceutically acceptable salts thereof.

22. A compound selected from the group consisting of:

(5S)-2,2-dimethyl-5-((1S)-3-methyl-1-{[4-(2-pyridinyl)-1-piperazinyl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-((1S)-3-methyl-1-{[4-(3-phenyl-1,2,4-thiadiazol-5-yl)-1-piperazinyl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-[(1S)-3-methyl-1-({(2R)-2-methyl-4-[4-(trifluoromethyl) pyridin-2-yl]piperazin-1-yl}carbonyl)butyl]-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-((1S)-3-methyl-1-{[(2R)-2-methyl-4-(2-pyridinyl)piperazinyl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-((1S)-3-methyl-1-{[(2S)-2-methyl-4-pyridin-2-ylpiperazin-1-yl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-5-((1S)-4-(4-ethoxyphenyl)-1-{[(2R)-2-methyl-4-(2-pyridinyl) piperazinyl]carbonyl}butyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-4-(4-ethoxyphenyl)-1-{[(2S)-2-methyl-4-(2-pyridinyl)piperazinyl]carbonyl}butyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-4-(4-ethoxyphenyl)-1-{[(2R)-2-methyl-4-(2-pyrimidinyl)piperazinyl]carbonyl}butyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-4-(4-ethoxyphenyl)-1-{[(2R)-4-(2-fluorophenyl)-2-methyl piperazinyl]carbonyl}butyl)-2,2-dimethyl-1,3 -dioxolan-4-one;

(5S)-2,2-dimethyl-5-((1S)-3-methyl-1-{[(2R)-2-methyl-4-pyrimidin-2-ylpiperazin-1-yl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-((1S)-3-methyl-1-{[(2S)-2-methyl-4-(4-methylpyridin-2-yl) piperazin-1-yl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-5-[(1S)-1-({(2R)-4-[2-fluoro-5-(methyloxy)phenyl]-2-methylpiperazin-1-yl}carbonyl)-3-methylbutyl]-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(2-fluorophenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5R)-5-((1S)-1-{[4-(4-methoxyphenyl)piperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[2R)-4-(4-chloro-2-fluorophenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(5-chloropyridin-2-yl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5R)-5-((1S)-1-{[4-(4-fluorophenyl)piperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5R)-5-((1S)-1-{[(1S,4S)-5-(4-fluorophenyl)-2,5-diazabicyclo[2.2.1]hept-2-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5R)-2,2-dimethyl-5-{(1S)-3-methyl-1-[(4-pyridin-2-ylpiperazin-1-yl)carbonyl]butyl}-1,3-dioxolan-4-one;

(5R)-2,2-dimethyl-5-[(1S)-3-methyl-1-({4-[4-(trifluoromethy)phenyl]piperazin-1-yl}carbonyl)butyl]-1,3-dioxolan-4-one;

(5R)-5-((1S)-1-{[4-(2-fluorophenyl)piperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5R)-2,2-dimethyl-5-{(1S)-3-methyl-1-[(4-pyrimidin-2-ylpiperazin-1-yl)carbonyl]butyl}-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-{(1S)-3-methyl-1-[((2R)-2-methyl-4-{4-[(trifluoromethyl)oxy]phenyl}piperazin-1-yl)carbonyl]butyl}-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-biphenyl-4-yl-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2S)-4-(2-fluorophenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(3-chlorophenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5R)-2,2-dimethyl-5-((1S)-3-methyl-1-{[4-(5-phenyl-1,2,4-oxadiazol-3-yl)-1-piperazinyl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-((1S)-3-methyl-1-{[(2R)-2-methyl-4-(5-phenylpyridin-2-yl)piperazin-1-yl]carbonyl}butyl)-1,3-dioxolan-4-one;

3-[(4-biphenyl-4-ylpiperazin-1-yl)carbonyl]-3,4-dideoxy-1,2-O-(1-methylethylidene)-5-O-(phenylmethyl)-L-threo-pentonic acid;

(5R)-2,2-dimethyl-5-((1S)-3-methyl-1-{[4-(5-pyridin-4-yl-1,2,4-oxadiazol-3-yl) piperazin-1-yl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[4-(2-fluorophenyl)-1-piperazinyl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5R)-2,2-dimethyl-5-[1S)-3-methyl-1-({4-[5-(2-thienyl)-1,2,4-oxadiazol-3-yl]piperazin-1-yl}carbonyl)butyl]-1,3-dioxolan-4-one;

(5R)-5-(1-{[(2R)-4-(5-chloropyridin-2-yl)-2-methylpiperazin-1-yl]carbonyl}-3-methyl butyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5R)-5-((1S)-1-{[4-(5-chloropyridin-2-yl)piperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5R)-5-((1S)-1-{[4-(5-bromopyridin-2-yl)piperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1R)-1-{[(2R)-4-(4-chlorophenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-[(1R)-3-methyl-1-({(2R)-2-methyl-4-[5-(trifluoromethyl) pyridin-2-yl]piperazin-1-yl}carbonyl)butyl]-1,3-dioxolan-4-one;

(5R)-5-((1S)-1-benzyl-2-oxo-2-{4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}ethyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-benzyl-2-{(2R)-2-methyl-4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}-2-oxoethyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5R)-2,2-dimethyl-5-((1S)-1-methyl-2-oxo-2-{4- [4-(trifluoromethoxy)phenyl]piperazin-1-yl}ethyl)-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-(1-methyl-2-{(2R)-2-methyl-4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}-2-oxoethyl)-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(4′-fluorobiphenyl-4-yl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1R)-1-{[(2R)-4-(4-ethoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(3,4-dimethoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-[3-methyl-1-({(2R)-2-methyl-4-[4-(methylsulfonyl)phenyl]piperazin-1-yl}carbonyl)butyl]-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(6-methoxy-2-naphthyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-[(1S)-1-({(2R)-4-[4-(1-benzofuran-3-yl)phenyl]-2-methylpiperazin-1-yl}carbonyl)-3-methylbutyl]-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-((1S)-3-methyl-1-{[(2R)-2-methyl-4-(4-propoxyphenyl)piperazin-1-yl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-[(1S)-3-methyl-1-({(2R)-2-methyl-4-[4-(trifluoromethyl)phenyl]piperazin-1-yl}carbonyl)butyl]-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(4-tert-butylphenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(5-fluoropyrimidin-2-yl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-((1S)-3-methyl-1-{[(2R)-2-methyl-4-(4-propylphenyl)piperazin-1-yl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-(cyclopentylmethyl)-2-{(2R)-2-methyl-4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}-2-oxoethyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(2,3-dihydro-1-benzofuran-5-yl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(1,3-benzodioxol-5-yl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(4-methoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-{(1S)-3-methyl-1-[((2R)-2-methyl-4-{4-[(trifluoromethyl)sulfonyl]phenyl}piperazin-1-yl)carbonyl]butyl}-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(4′-methoxybiphenyl-4-yl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-(1-{[(2R)-4-(4-cyclohexylphenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(1-benzofuran-5-yl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(2,2-difluoro-1,3-benzodioxol-5-yl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-(1-{[(2R)-4-(3-fluoro-4-methoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(3-fluoro-4-isopropoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-[(1S)-1-({(2R)-4-[3-fluoro-4-(trifluoromethoxy)phenyl]-2-methylpiperazin-1-yl}carbonyl)-3-methylbutyl]-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-((1S)-3-methyl-1-{[(2R)-2-methyl-4-quinolin-3-ylpiperazin-1-yl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-2,2-dimethyl-5-((1S)-3-methyl-1-{[(2R)-2-methyl-4-(4-methylphenyl)piperazin-1-yl]carbonyl}butyl)-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(5-chloro-2-thienyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one;

(5S)-5-((1S)-1-{[(2R)-4-(3-methoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one.

23. A compound according to Formula (V):

wherein A is selected from —C(B)—and N;

R 1 is selected from C 1 -C 6 alkyl, C 3 -C 8 -cycloalkyl, aryl, pyridinyl, pyrazinyl, thiadiazolyl, pyrimidinyl, oxadiazolyl, quinolinyl, thienyl, benzofuranyl, amino and alkoxy;

R 2 is selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 3 -C 8 -cycloalkyl, and aryl;

R 4 , R 5 , R 6 and R 7 are independently selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl; or R 4 and R 7 form together a —CH 2 — linkage;

n is an integer selected from 1, 2, 3, 4, 5 and 6;

wherein R 1 , R 2 , R 4 , R 5 , R 6 and R 7 may be substituted by from 1to 5substituents selected from the group consisting of C 1 -C 6 -alkyl, amino, halogen, carboxy, trihalomethyl, cyano, hydroxy, mercapto, and nitro;

Carbons (2) and (3) are two chiral centers, wherein chiral center (2) has a configuration selected from “S” and “R” and wherein chiral center (3) has a “S” configuration as well as pharmaceutically acceptable salts thereof.

24. A compound selected from the group consisting of:

(2S,3S)-2-hydroxy-5-methyl-3-[(4-pyridin-2-ylpiperazin-1-yl)carbonyl]hexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-{[4-(3-phenyl-1,2,4-thiadiazol-5-yl)piperazin-1-yl]carbonyl}hexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-({(2R)-2-methyl-4-[4-(trifluoromethyl)pyridin-2-yl]piperazin-1-yl}carbonyl)hexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-{[(2R)-2-methyl-4-pyridin-2-ylpiperazin-1-yl]carbonyl}hexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-{[(2S)-2-methyl-4-pyridin-2-ylpiperazin-1-yl]carbonyl}hexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-{[(2R)-2-methyl-4-pyrimidin-2-ylpiperazin-1-yl]carbonyl}hexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-{[(2S)-2-methyl-4-(4-methylpyridin-2-yl)piperazin-1-yl]carbonyl}hexanoic acid;

(2S,3S)-3-{[(2R)-4-(2-fluoro-5-methoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(2-fluorophenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2R,3S)-2-hydroxy-3-{[4-(4-methoxyphenyl)piperazin-1-yl]carbonyl}-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(4-chloro-2-fluorophenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(5-chloropyridin-2-yl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2R,3S)-3-{[4-(4-fluorophenyl)piperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2R,3S)-2-hydroxy-5-methyl-3-[(4-pyridin-2-ylpiperazin-1-yl)carbonyl]hexanoic acid;

(2R,3S)-2-hydroxy-5-methyl-3-({4-[4-(trifluoromethyl)phenyl]piperazin-1-yl}carbonyl)hexanoic acid;

(2R,3S)-3-{[4-(2-fluorophenyl)piperazin 1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2R,3S)-2-hydroxy-5-methyl-3-[(4-pyrimidin-2-ylpiperazin-1-yl)carbonyl]hexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-({(2R)-2-methyl-4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}carbonyl)hexanoic acid;

(2S,3S)-3-{[(2R)-4-biphenyl-4-yl-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2S)-4-(2-fluorophenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(3-chlorophenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2R,3S)-2-hydroxy-5-methyl-3-{[4-(5-phenyl-1,2,4-oxadiazol-3-yl)piperazin-1-yl]carbonyl}hexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-{[(2R)-2-methyl-4-(5-phenylpyridin-2-yl)piperazin-1-yl]carbonyl}hexanoic acid;

5-O-benzyl-3-[(4-biphenyl-4-ylpiperazin-1-yl)carbonyl]-3,4-dideoxy-L-threo-pentonic acid;

(2R,3S)-2-hydroxy-5-methyl-3-{[4-(5-pyridin-4-yl-1,2,4-oxadiazol-3-yl)piperazin-1-yl]carbonyl}hexanoic acid;

(2S,3S)-3-{[4-(2-fluorophenyl)piperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2R,3S)-2-hydroxy-5-methyl-3-({4-[5-(2-thienyl)-1,2,4-oxadiazol-3-yl]piperazin-1-ylcarbonyl)hexanoic acid;

(2R,3S)-3-{[(2R)-4-(5-chloropyridin-2-yl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2R,3S)-3-{[4-(5-chloropyridin-2-yl)piperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2R,3S)-3-{[4-(5-bromopyridin-2-yl)piperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(4-chlorophenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-({(2R)-2-methyl-4-[5-(trifluoromethyl)pyridin-2-yl]piperazin-1-yl}carbonyl)hexanoic acid;

(2R,3S)-3-benzyl-2-hydroxy-4-oxo-4-{4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}butanoic acid;

(2S,3S)-3-benzyl-2-hydroxy-4-{(2R)-2-methyl-4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}-4-oxobutanoic acid;

(2R,3S)-2-hydroxy-3-methyl-4-oxo-4-{4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}butanoic acid;

(2S)-2-hydroxy-3-methyl-4-{(2R)-2-methyl-4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}-4-oxobutanoic acid;

(2S,3S)-3-{[(2R)-4-(4′-fluorobiphenyl-4-yl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(4-ethoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(3,4-dimethoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-({(2R)-2-methyl-4-[4-(methylsulfonyl)phenyl]piperazin-1-yl}carbonyl)hexanoic acid;

(2S,3S)-2-hydroxy-3-{[(2R)-4-(6-methoxy-2-naphthyl)-2-methylpiperazin-1-yl]carbonyl}-5-methylhexanoic acid;

(2S,3S)-3-({(2R)-4-[4-(1-benzofuran-3-yl)phenyl]-2-methylpiperazin-1-yl}carbonyl)-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-{[(2R)-2-methyl-4-(4-propoxyphenyl)piperazin-1-yl]carbonyl}hexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-({(2R)-2-methyl-4-[4-(trifluoromethyl)phenyl]piperazin-1-yl}carbonyl)hexanoic acid;

(2S,3S)-3-{[(2R)-4-(4-tert-butylphenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(5-fluoropyrimidin-2-yl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-{[(2R)-2-methyl-4-(4-propylphenyl)piperazin-1-yl]carbonyl}hexanoic acid;

(2S,3S)-3-(cyclopentylmethyl)-2-hydroxy-4-{(2R)-2-methyl-4-[4-(trifluoromethoxy)phenyl]piperazin-1-yl}-4-oxobutanoic acid;

(2S,3S)-3-{[(2R)-4-(2,3-dihydro-1-benzofuran-5-yl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(1,3-benzodioxol-5-yl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-2-hydroxy-3-{[(2R)-4-(4-methoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-5-methylhexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-[((2R)-2-methyl-4-{4-[(trifluoromethyl)sulfonyl]phenyl}piperazin-1-yl)carbonyl]hexanoic acid;

(2S,3S)-2-hydroxy-3-{[(2R)-4-(4′-methoxybiphenyl-4-yl)-2-methylpiperazin-1-yl]carbonyl}-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(4-cyclohexylphenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(1-benzofuran-5-yl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(2,2-difluoro-1,3-benzodioxol-5-yl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(3-fluoro-4-methoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-{[(2R)-4-(3-fluoro-4-isopropoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-3-({(2R)-4-[3-fluoro-4-(trifluoromethoxy)phenyl]-2-methylpiperazin-1-yl}carbonyl)-2-hydroxy-5-methyl hexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-{[(2R)-2-methyl-4-quinolin-3-ylpiperazin-1-yl]carbonyl}hexanoic acid;

(2S,3S)-2-hydroxy-5-methyl-3-{[(2R)-2-methyl-4-(4-methylphenyl)piperazin-1-yl]carbonyl}hexanoic acid;

(2S,3S)-3-{[(2R)-4-(5-chloro-2-thienyl)-2-methylpiperazin-1-yl]carbonyl}-2-hydroxy-5-methylhexanoic acid;

(2S,3S)-2-hydroxy-3-{[(2R)-4-(3-methoxyphenyl)-2-methylpiperazin-1-yl]carbonyl}-5-methylhexanoic acid.