1-methylpyrazole-piperazine compounds having multimodal activity against pain

1. A compound of formula (I):

wherein

n is 1, 2, 3, 4, 5 or 6;

Y—W is CR Y —N;

X is a bond or —CR 6 R 6 —;

R 1 is substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heterocyclyl;

R 2 is substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl, substituted or unsubstituted C 2-6 alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heterocyclyl;

R 3 is hydrogen, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl, substituted or unsubstituted C 2-6 alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted alkylcycloalkyl, substituted or unsubstituted alkylaryl, or substituted or unsubstituted alkylheterocyclyl;

R 4 , R 4′ , R 4″ and R 4′″ are independently selected from hydrogen or unsubstituted C 1-6 alkyl, unsubstituted C 2-6 alkenyl, and unsubstituted C 2-6 alkynyl;

R 5 and R 5′ are independently selected from hydrogen or unsubstituted C 1-6 alkyl, unsubstituted C 2-6 alkenyl, and unsubstituted C 2-6 alkynyl;

R 6 is selected from hydrogen, halogen, —OR 7 , substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl, substituted or unsubstituted C 2-6 alkynyl, —C(O)OR 7 , —C(O)NR 7 R 7′ , —NR 7 C(O)R 7′ , and —NR 7 R 7′″ —;

R 6′ is selected from hydrogen, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl, and substituted or unsubstituted C 2-6 alkynyl;

wherein R 7 and R 7′ are independently selected from hydrogen, unsubstituted C 1-6 alkyl, unsubstituted C 2-6 alkenyl, unsubstituted C 2-6 alkynyl , and unsubstituted acetyl;

and R 7′″ is selected from hydrogen, unsubstituted C 1-6 alkyl, unsubstituted C 2-6 alkenyl, unsubstituted C 2-6 alkynyl and -Boc;

R y is selected from hydrogen, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl, and substituted or unsubstituted C 2-6 alkynyl;

optionally as a stereoisomer, a racemate or a mixture of at least two of stereoisomers, in any mixing ratio, or a corresponding salt thereof.

2. The compound according to claim 1 , wherein

R 1 is substituted or unsubstituted aryl or substituted or unsubstituted heterocyclyl; and/or

R 2 is substituted or unsubstituted aryl or substituted or unsubstituted heterocyclyl;

and/or

R 3 is hydrogen, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl, or substituted or unsubstituted C 2-6 alkynyl.

3. The compound according to claim 2 , wherein R 3 is hydrogen or substituted or unsubstituted C 1-6 alkyl.

4. The compound according to claim 2 , wherein

R 1 is substituted or unsubstituted aryl or substituted or unsubstituted heterocyclyl;

R 2 is substituted or unsubstituted aryl or substituted or unsubstituted heterocyclyl; and

R 3 is hydrogen, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl, or substituted or unsubstituted C 2-6 alkynyl.

5. The compound according to claim 4 , wherein R 3 is hydrogen or substituted or unsubstituted C 1-6 alkyl.

6. The compound according to claim 1 , wherein X is a bond.

7. The compound according to claim 1 , wherein n is 1 or 2, X is a bond, and R 2 is a substituted or unsubstituted group selected from phenyl, pyridine, and thiazole.

8. The compound according to claim 1 , wherein R 1 is a substituted or unsubstituted group selected from phenyl and pyridine; and/or

wherein R 3 is methyl and R 4 , R 4′ , R 4″ and R 4′″ are all hydrogen.

9. The compound according to claim 1 , which is selected from:

1-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)-4-(2-(pyridin-2-yl)ethyl)piperazine,

1-benzyl-4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazine,

1-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)-4-phenethylpiperazine,

1-((1-methyl-1H-pyrazol-5-yl)(pyridin-2-yl)methyl)-4-phenethylpiperazine,

1-((1-methyl-1H-pyrazol-5-yl)(pyridin-3-yl)methyl)-4-phenethylpiperazine,

1-(2-methoxyphenethyl)-4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazine,

1-((3-methoxyphenyl)(1-methyl-1H-pyrazol-5-yl)methyl)-4-phenethylpiperazine,

1-((2-methoxyphenyl)(1-methyl-1H-pyrazol-5-yl)methyl)-4-phenethylpiperazine,

1-((4-methoxyphenyl)(1-methyl-1H-pyrazol-5-yl)methyl)-4-phenethylpiperazine,

1-((1-methyl-1H-pyrazol-1-5-yl)(6-(trifluoromethyl)pyridin-2-yl)methyl)-4-phenethylpiperazine,

1-((1-methyl-1H-pyrazol-5-yl)(6-(trifluoromethyl)pyridin-3-yl)methyl)-4-phenethylpiperazine,

1-((5-fluoropyridin-2-yl)(1-methyl-1H-pyrazol-5-yl)methyl)-4-phenethylpiperazine,

1-((5-fluoropyridin-3-yl)(1-methyl-1H-pyrazol-5-methyl)-4-phenethylpiperazine,

1-((1-methyl-1H-pyrazol-5-yl)(5-(trifluoromethyl)pyridin-2-yl)methyl)-4-phenethylpiperazine,

1-((5-fluoropyridin-2-yl)(1-methyl-1H-pyrazol-5-yl)methyl)-4-(2-(pyridin-2-yl)ethyl)piperazine,

1-((3-fluoropyridin-2-yl)(1-methyl-1H-pyrazol-5-methyl)-4-phenethylpiperazine,

1-((1-methyl-1H-pyrazol-5-yl)(2-(trifluorornethyl)pyridin-3-yl)methyl)-4-phenethylpiperazine,

1-((5-chloropyridin-2-yl)(1-methyl-1H-pyrazol-5-yl)methyl)-4-phenethylpiperazine,

1-((1-methyl-1H-pyrazol-5-yl)(4-(trifluorornethyl)pyridin-3-yl)methyl)-4-phenethylpiperazine,

1-((1-methyl-1H-pyrazol-5-yl)(pyridin-4-yl)methyl)-4-phenethylpiperazine,

1-(3-methoxyphenethyl)-4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazine,

1-(2-fluorophenethyl)-4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazine,

1-(4-fluorophenethyl)-4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazine,

1-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)-4-(2-(6-(trifluorornethyl)pyridin-3-yl)ethyl)piperazine,

tert-butyl 4-(2-(4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazin-1-yl)ethyl)thiazol-2-ylcarbaniate,

1-(2-fluorophenethyl)-4-((5-fluoropyridin-2-yl)(1-methyl-1H-pyrazol-5-yl)methyl)piperazine,

1-((5-fluoropyridin-2-yl)(1-methyl-1H-pyrazol-5-yl)methyl)-4-(3-methoxyphenethyl)piperazine,

2-(2-(4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazin-1-yl)ethyl)phenol,

3-((1-methyl-1H-pyrazol-5-yl)(4-phenethylpiperazin-1-yl)methyl)phenol,

3-(2-(4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazin-1-yl)ethyl)phenol,

3-(2-(4-((5-fluoropyridin-2-yl)(1-methyl-1H-pyrazol-5-yl)methyl)piperazin-1-yl)ethyl)phenol,

4-(2-(4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazin-1-yl)ethyl)thiazol-2-amine,

1-(2-(3-fluoropyridin-2-yl)ethyl)-4-((1methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazine,

1-(2-(5-fluoropyridin-2-yl)ethyl)-4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazine,

1-(3-fluorophenethyl)-4-((1methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazine,

1-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)-4-(2-(pyridin-3-yl)ethyl)piperazine,

1-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)-4-(2-(pyridin-4-yl)ethyl)piperazine,

1-(3-fluorophenethyl)-4-((5-fluoropyridin-2-yl)(1-methyl-1H-pyrazol-5-yl)methyl)piperazine,

2-(4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazin-1-yl)-1-phenylethanol,

6-(2-(4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazin-1-yl)ethyl)pyridin-2-amine,

1-(2-(3-chloropyridin-2-yl)ethyl)-4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazine,

1-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)-4-(2-(6-(trifluoromethyl)pyridin-2-yl)ethyl)piperazine,

1-(2-(3-chloropyridin-2-yl)ethyl)-4-((5-fluoropyridin-2-yl)(1-methyl-1H-pyrazol-5-yl)methyl)piperazine,

N-(6-(2-(4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazin-1-yl)ethyl)pyridin-2-yl)methanesulfonamide, and

N-(6-(2-(4-((1-methyl-1H-pyrazol-5-yl)(phenyl)methyl)piperazin-1-yl)ethyl)pyridin-2-yl)-N-(methylsulfonyl)methanesulfonamide,

optionally as a stereoisomer, a racemate or a mixture of at least two stereoisomers, in any mixing ratio, or a corresponding salt thereof.

10. A process for preparing a compound of formula (I) according to claim 1

which process comprises

(a) reducing a compound of formula VI

(b) reacting a compound of formula IV

with a suitable reagent of formula Va, Vb or Vc,

wherein L is a leaving group,

or

(c) reacting a compound of formula II

first with methanesulfonyl chloride followed by an alkylation reaction with a compound of formula VII

11. A process for the preparation of the compound of formula (I) according to claim 1 , employing a compound of Formula (II), (III), (IV), (Va), (Vb), (Vc), Vd), (VI) or (VII)

wherein n, X, R 1 , R 2 , R 3 , R 4 , R 4′ , R 4″ , R 4′″ , R 5 and R 5′ have the meanings as defined in claim 1 for the compound of formula (I), P represents a suitable protecting group, and L is a leaving group.

12. A pharmaceutical composition comprising the compound according to claim 1 , or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, adjuvant or vehicle.

13. A method of treating pain in a subject in need thereof, comprising administration of an effective amount of the compound according to claim 1 .

14. The method according to claim 13 , wherein the pain is selected from medium to severe pain, visceral pain, chronic pain, cancer pain, migraine, inflammatory pain, acute pain, neuropathic pain, allodynia, and hyperalgesia.

15. The process according to claim 10 , wherein L is a leaving group selected from the group consisting of chloro, bromo, mesylate and tosylate.

16. The process according to claim 11 , wherein L is a leaving group selected from the group consisting of chloro, bromo, mesylate and tosylate.

17. The process according to claim 11 , wherein P is Boc.

18. A compound which is selected from:

N-(1-methyl-1H-pyrazol-5-yl)-1-phenethyl-N-phenylpiperidin-4-amine,

and

1-benzyl-N-(1-methyl-1H-pyrazol-5-yl)-N-phenylpiperidin-4-amine,

optionally as a stereoisomer, a racemate or a mixture of at least two stereoisomers, in any mixing ratio, or a corresponding salt thereof.

19. A pharmaceutical composition comprising the compound according to claim 18 , or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, adjuvant or vehicle.

20. A method of treating pain in a subject in need thereof, comprising administration of an effective amount of the compound according to claim 18 .

21. The method according to claim 20 , wherein the pain is selected from medium to severe pain, visceral pain, chronic pain, cancer pain, migraine, inflammatory pain, acute pain, neuropathic pain, allodynia, and hyperalgesia.