Carbamoyloxy arylalkan arylpiperazine analgesics

1. A compound of Formula 1:

or a pharmaceutically acceptable salt thereof, wherein - - - denotes an optional bond forming a cyclic moiety;

R 1 and R 2 are H—, or R 1 and R 2 are taken together with the phenyl to form benzo[d][1,3]oxazin-2-one moiety;

X 1 is one or more substituents independently selected from the group consisting of H-, straight- or branched-chain C 1 -C 6 alkyl, fluoro, chloro, bromo, straight- or branched-chain C 1 -C 6 alkoxy, nitro, dimethylamino and trifluoromethyl, or

X 1 is taken together with the phenyl to form naphthyl or methylenedioxyphenyl;

z is H— or fluoro;

Ar is selected from the group consisting of phenyl, pyridinyl, pyrimidinyl, naphthyl, dihydrobenzodioxinyl, methylenedioxyphenyl and quinoxalinyl, wherein each of phenyl, pyridinyl and pyrimidinyl is optionally substituted by one or more substituents independently selected from the group consisting of H-, straight- or branched-chain C 1 -C 6 alkyl, hydroxy, halo, straight- or branched-chain C 1 -C 6 alkoxy, nitro, acetyl, t-butylacetyl, trifluoromethyl, trifluoromethoxy, amino, benzyloxy, t-butylcarbonyloxy, benzyloxycarbonyloxy, ethanoyloxy, and cyclopentyloxy;

each of Y 1 , Y 2 and Y 4 is independently H— or methyl;

Y 3 is H— or phenyl;

n is 1 or 2; and

m is 0 or 1.

2. The compound of claim 1 , wherein each of R 1 , R 2 and X 1 is H—.

3. The compound of claim 1 , wherein n is 1; and m is 0.

4. The compound of claim 1 , wherein Ar is phenyl substituted with straight- or branched-chain C 1 -C 6 alkoxy.

5. The compound of claim 4 , which is selected from the group consisting of:

carbamic acid 3-[4-(2,4-dimethoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(3-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(2-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(3,5-dimethoxy-phenyl)-piperazin-1-yl]1-phenyl-propyl ester;

carbamic acid 3-[4-(5-chloro-2-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-(4-nitro-phenyl)-propyl ester;

carbamic acid 1-(3-chloro-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(2-fluoro-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(4-methoxy-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(4-tert-butyl-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(2-chloro-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-(2-trifluoromethyl-phenyl)-propyl ester;

carbamic acid 1-(3,4-difluoro-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(3-fluoro-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(3-methoxy-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-p-tolyl-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-m-tolyl-propyl ester;

carbamic acid 1-(2,4-dichloro-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-o-tolyl-propyl ester;

carbamic acid 1-(2,4-dimethyl-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(3,4-dimethyl-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(2,5-dimethyl-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(4-chloro-3-trifluoromethyl-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-(2-nitro-phenyl)-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]1-(3-nitro-phenyl)-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]1-(4-trifluoromethyl-phenyl)-propyl ester;

carbamic acid 1-benzol[1,3]dioxol-5-yl-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-(3-trifluoromethyl-phenyl)-propyl ester;

carbamic acid 1-(2-fluoro-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(3,4-dichloro-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(4-chloro-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(5-chloro-2-methoxy-phenyl)-piperazin-1-yl]-1-(4-fluoro-phenyl)-propyl ester;

carbamic acid 1-(4-fluoro-phenyl)-3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(4-fluoro-phenyl)-3-[4-(2-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(4-chloro-phenyl)-3-[4-(2-methoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 4-[4-(2-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-butyl ester;

carbamic acid (R)-3-[4-(4-methoxy-phenyl)-2,6-dimethyl-piperazin-1-yl]-1-phenyl-propyl ester;

(R)-carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

(S)-carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

4-{2-[4-(4-methoxy-phenyl)-piperazin-1-yl]-ethyl}-1,4-dihydro-benzo[d][1,3]oxazin-2-one;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-butyl ester; and

carbamic acid 3-[4-(3,4-dimethoxy-phenyl)-piperazin-1-yl]-1-phenyl-butyl ester.

6. The compound of claim 1 , which is selected from the group consisting of:

carbamic acid 1-phenyl-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(4-chloro-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(4-dimethylamino-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(3-nitro-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(4-tert-butyl-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(4-fluoro-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(3-chloro-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(4-methoxy-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(4-nitro-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 3-(4-phenyl-piperazin-1-yl)-1-p-tolyl-propyl ester;

carbamic acid 3-[4-(2,3-dihydro-benzo[1,4]dioxin-6-yl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 1-phenyl-3-[4-(4-trifluoromethoxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(2,4-dimethyl-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 1-phenyl-3-[4-(2-trifluoromethyl-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-phenyl-3-[4-(2-chloro-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-phenyl-3-[4-(4-nitro-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(4-chloro-3-trifluoromethyl-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(2,6-dimethyl-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(4-fluoro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(4-chloro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(2-hydroxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 1-phenyl-3-(4-m-tolyl-piperazin-1-yl)-propyl ester;

carbamic acid 3-[4-(3,4-dimethyl-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-(4-benzo[1,3]dioxol-5-yl-piperazin-1-yl)-1-phenyl-propyl ester;

carbamic acid 3-[4-(3,4-dichloro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(2-nitro-4-trifluoromethyl-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(3-chloro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 1-phenyl-3-(4-o-tolyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-phenyl-3-(4-p-tolyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-phenyl-3-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-phenyl-3-[4-(4-trifluoromethyl-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(2-fluoro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(3-fluoro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(2-nitro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 1-(4-chloro-3-trifluoromethyl-phenyl)-3-[4-(4-hydroxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(3,4-dichloro-phenyl)-3-[4-(4-hydroxy-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(2-ethoxy-phenyl)-piperazin-1-yl]-1-(4-fluoro-phenyl)-propyl ester;

carbamic acid 3-[4-(3,4-dichloro-phenyl)-piperazin-1-yl]-1-(4-fluoro-phenyl)-propyl ester;

carbamic acid 1-(4-fluoro-phenyl)-3-[4-(4-nitro-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 1-(4-fluoro-phenyl)-3-(4-o-tolyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(4-fluoro-phenyl)-3-[4-(4-fluoro-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(4-hydroxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(4-benzyloxyphenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

acetic acid 4-[4-(3-carbamoyloxy-3-phenyl-propyl)-piperazin-1-yl]-phenyl ester;

carbamic acid 3-[4-(4-cyclopentyloxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 1-(4-fluoro-phenyl)-3-[4-(4-hydroxy-phenyl)-piperazin-1-yl]-propyl ester;

1-(4-fluorophenyl)-3-(4-(4-(pivaloyloxy)phenyl)piperazin-1-yl)-propyl carbamate;

carbonic acid 4-{4-[3-carbamoyloxy-3-(4-fluoro-phenyl)-propyl]-piperazin-1-yl}-phenyl ethyl ester;

carbonic acid benzyl ester 4-{4-[3-carbamoyloxy-3-(4-fluoro-phenyl)-propyl]-piperazin-1-yl}-phenyl ester;

acetic acid 4-{4-[3-carbamoyloxy-3-(4-fluoro-phenyl)-propyl]-piperazin-1-yl}-phenyl ester;

carbamic acid 1-phenyl-4-(4-phenyl-piperazin-1-yl)-butyl ester;

carbamic acid 3-(4-benzo[1,3]dioxol-5-ylmethyl-piperazin-1-yl)-1-phenyl-propyl ester;

carbamic acid 3-(4-benzyl-piperazin-1-yl)-1-phenyl-propyl ester

(R)-carbamic acid 3-[4-(4-chloro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

(R)-carbamic acid 3-[4-(4-fluoro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

(R)-carbamic acid 3-[4-(4-hydroxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(4-chloro-phenyl)-piperazin-1-yl]-1-phenyl-butyl ester;

carbamic acid 3-[4-(4-nitro-phenyl)-piperazin-1-yl]-1-phenyl-butyl ester;

carbamic acid 3-[4-(3,4-dimethyl-phenyl)-piperazin-1-yl]1-phenyl-butyl ester;

carbamic acid 3-[4-(4-quinoxalinyl)-piperazin-1-yl]-1-phenyl-butyl ester;

carbamic acid 3-[4-(3,4-dichloro-phenyl)-piperazin-1-yl]-1-phenyl-butyl ester;

carbamic acid 3-[4-(2,4-difluoro-phenyl)-piperazin-1-yl]-1-phenyl-butyl ester; and

carbamic acid 2-fluoro-1-phenyl-3-(4-phenyl-piperazin-1-yl)-propyl ester.

7. The compound of claim 1 , which is selected from the group consisting of:

carbamic acid 1-phenyl-3-(4-pyridin-2-yl-piperazin-1-yl)-propyl ester;

carbamic acid 3-[4-(3-chloro-pyridin-2-yl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(3,5-dichloro-pyridin-2-yl-piperazin-1-yl]-1-phenyl-butyl ester;

carbamic acid 1-phenyl-4-(4-pyridin-2-yl-piperazin-1-yl)-butyl ester;

carbamic acid 4-[4-(3-chloro-pyridin-2-yl)-piperazin-1-yl]-1-phenyl-butyl ester; and

carbamic acid 1-phenyl-3-(4-pyrimidin-2-yl-piperazin-1-yl)-propyl ester.

8. The compound of claim 1 , which is selected from the group consisting of:

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]1-naphthalen-2-yl-propyl ester; and

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-naphthalen-1-yl-propyl ester.

9. The compound of claim 1 , which is selected from the group consisting of:

carbamic acid (R)-3-[4-(4-methoxy-phenyl)-2,6-dimethyl-piperazin-1-yl]-1-phenyl-propyl ester;

(R)-carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

(R)-carbamic acid 3-[4-(4-chloro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

(R)-carbamic acid 3-[4-(4-fluoro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

(R)-carbamic acid 3-[4-(4-hydroxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester; and

(S)-carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester.

10. The compound of claim 1 , wherein the compound is selected from the group consisting of:

carbamic acid 1-(4-chloro-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(4-fluoro-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(4-nitro-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-phenyl-3-[4-(4-nitro-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(4-fluoro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester; and

(R)-carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester.

11. The compound of claim 1 , wherein the compound is (R)-carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester.

12. A compound which is selected from the group consisting of:

carbamic acid 2-[4-(4-methoxy-phenyl)-piperazin-1-ylmethyl]-1,2,3,4-tetrahydro-naphthalen-1-yl ester;

carbamic acid 3-{4-[bis-(4-fluoro-phenyl)-methyl]-piperazin-1-yl}-1-phenyl-propyl ester; and

carbamic acid 3-(4-benzoyl-piperazin-1-yl)-1-phenyl-propyl ester.

13. A pharmaceutical composition comprising a therapeutically effective amount of the compound of claim 1 and a pharmaceutically acceptable carrier.

14. The pharmaceutical composition of claim 13 , wherein the compound is selected from the group consisting of:

carbamic acid 1-(4-chloro-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(4-fluoro-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-(4-nitro-phenyl)-3-(4-phenyl-piperazin-1-yl)-propyl ester;

carbamic acid 1-phenyl-3-[4-(4-nitro-phenyl)-piperazin-1-yl]-propyl ester;

carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester;

carbamic acid 3-[4-(4-fluoro-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester; and

(R)-carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester.

15. The pharmaceutical composition of claim 13 , wherein the compound is (R)-carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester.

16. The pharmaceutical composition of claim 13 , wherein the therapeutically effect amount is in the range of 10 to 500 mg.

17. A method for treating pain, anxiety or depression, comprising administering to a patient in need of treatment an effective amount of the compound of claim 1 .

18. The method of claim 17 , wherein the compound is (R)-carbamic acid 3-[4-(4-methoxy-phenyl)-piperazin-1-yl]-1-phenyl-propyl ester.

19. The method of claim 17 , wherein the pain is selected from the group consisting of acute pain, chronic pain, neuropathic pain, post-surgery neuropathic pain, diabetic pain, postherpetic neuralgia, inflammatory pain, joint pain and migraine headache.

20. The method of claim 17 , wherein the therapeutically effect amount is in the range of 10 to 500 mg.