Substituted morpholine derivatives having activity against pain

1. A compound of general Formula (I):

wherein

R 1 is

m is 1, 2, 3, 4 or 5;

n is 0, 1, 2, 3, 4 or 5;

p is 0 or 1;

q is 0, 1 or 2;

r is 0, 1 or 2;

Y is —CH 2 — or —C(O)—;

X is a bond, —C(R x R x′ )—, —C(O)—, —O—, —C(O)NR 7 —, —NR 7 C(O)— or —C(O)O—;

wherein R x is selected from the group consisting of halogen or substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl substituted or unsubstituted C 2-6 alkynyl, and —OR 7 ;

R x′ is selected from the group consisting of hydrogen, halogen or substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl and substituted or unsubstituted C 2-6 alkynyl;

R 7 is selected from the group consisting of hydrogen, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl and substituted or unsubstituted C 2-6 alkynyl;

R 1′ is selected from the group consisting of 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 and substituted or unsubstituted heterocyclyl;

R 2 is selected from the group consisting of 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 and substituted or unsubstituted heterocyclyl,

R 3 and R 3′ are independently selected from the group consisting of hydrogen, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl and substituted or unsubstituted C 2-6 alkynyl; or

R 3 and R 3′ , together with the carbon atom to which they are attached, form a substituted or unsubstituted cycloalkyl;

R 4 and R 4′ are independently selected from the group consisting of hydrogen, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl, substituted or unsubstituted C 2-6 alkynyl, —CHOR 9 and —C(O)OR 9 ;

wherein R 9 is selected from the group consisting of hydrogen, substituted or unsubstituted C 1-9 alkyl, substituted or unsubstituted C 2-9 alkenyl and substituted or unsubstituted C 2-9 alkynyl;

R 5 and R 5′ are independently selected from the group consisting of 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, —CHOR 8 and —C(O)OR 8 ;

wherein R 8 is selected from the group consisting of hydrogen, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl and substituted or unsubstituted C 2-6 alkynyl; or

R 5 and R 5′ , together with the carbon atom to which they are attached, form a substituted or unsubstituted cycloalkyl or a substituted or unsubstituted heterocyclyl;

R 6 and R 6′ are independently selected from the group consisting of hydrogen, substituted or unsubstituted C 1-6 alkyl, substituted or unsubstituted C 2-6 alkenyl, substituted or unsubstituted C 2-6 alkynyl, —CHOR 10 and —C(O)OR 10 ;

wherein R 10 is selected from the group consisting of 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, including enantiomers and diastereomers, a racemate or a mixture of at least two stereoisomers, including enantiomers and/or diastereomers, in any mixing ratio, or a corresponding salt thereof, or a corresponding solvate thereof;

with the following proviso applying:

R 1 is not

when Y is —C(O)—.

2. The compound according to claim 1 , which is a compound of Formula (I′)

3. The compound according to claim 1 , which is a compound of Formula (I 2 ′)

4. The compound according to claim 1 , which is a compound of Formula (I 3 ′)

5. The compound according to claim 1 , which is a compound of Formula (I 4 ′), (I 4a ′), (I 4b ′) or (I 4c ′)

6. The compound according to claim 1 , which is a compound of Formula (I 5 ′), (I 5a ′), (I 5b ′) or (I 5c ′)

7. The compound according to claim 1 , wherein R 1′ is selected from the group consisting of substituted or unsubstituted C 1-6 alkyl and substituted or unsubstituted aryl.

8. The compound according to claim 7 , wherein R 1′ is a substituted or unsubstituted group selected from the group consisting of methyl, ethyl, isopropyl and phenyl.

9. The compound according to claim 1 , wherein R 2 is selected from the group consisting of substituted or unsubstituted C 1-6 alkyl, and substituted or unsubstituted aryl.

10. The compound according to claim 9 , wherein R 2 is a substituted or unsubstituted group selected from the group consisting of methyl, isopropyl, isobutyl and phenyl.

11. The compound according to claim 1 , wherein R 3 and R 3′ , together with the carbon atom to which they are attached, form a substituted or unsubstituted cycloalkyl.

12. The compound according to claim 11 , wherein R 3 and R 3′ form a substituted or unsubstituted C 3-6 cycloalkyl.

13. The compound according to claim 11 , wherein R 3 and R 3′ form a substituted or unsubstituted cyclopropyl.

14. The compound according to claim 1 , which is selected from the group consisting of:

7-(4-methoxybenzyl)-5-(1-phenethylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-8-one,

(5-(1-phenethylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-7-yl)(phenyl)methanone,

5-(1-benzylpiperidin-4-yl)-7-(4-methoxybenzyl)-4-oxa-7-azaspiro[2.5]octan-8-one,

(5-(1-benzylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-7-yl)(phenyl)methanone,

5-(1-benzylpiperidin-4-yl)-7-ethyl-4-oxa-7-azaspiro[2.5]octan-8-one,

5-(1-ethylpiperidin-4-yl)-7-(4-methoxybenzyl)-4-oxa-7-azaspiro[2.5]octan-8-one,

7-ethyl-5-(1-phenethylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-8-one,

7-isopropyl-5-(1-phenethylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-8-one,

5-(1-phenethylpiperidin-4-yl)-7-phenyl-4-oxa-7-azaspiro[2.5]octan-8-one,

5-(1-benzylpiperidin-4-yl)-7-phenyl-4-oxa-7-azaspiro[2.5]octan-8-one,

7-ethyl-5-(1-phenethylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octane,

5-(1-benzylpiperidin-4-yl)-7-(4-methoxybenzyl)-4-oxa-7-azaspiro[2.5]octane,

7-(4-methoxybenzyl)-5-(1-phenethylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octane and

5-(1-benzylpiperidin-4-yl)-7-ethyl-4-oxa-7-azaspiro[2.5]octane.

15. The compound according to claim 1 , which is selected from the group consisting of:

5-(1-isobutylpiperidin-4-yl)-7-(4-methoxybenzyl)-4-oxa-7-azaspiro[2.5]octan-8-one,

5-(1-isopentylpiperidin-4-yl)-7-(4-methoxybenzyl)-4-oxa-7-azaspiro[2.5]octan-8-one,

(2S,6R)-4-ethyl-6-(1-isopentylpiperidin-4-yl)-2-methylmorpholin-3-one,

(2S,6S)-4-ethyl-6-(1-isopentylpiperidin-4-yl)-2-methylmorpholin-3-one,

(2R,6R)-4-ethyl-6-(1-isopentylpiperidin-4-yl)-2-methylmorpholin-3-one,

(2R,6S)-4-ethyl-6-(1-isopentylpiperidin-4-yl)-2-methylmorpholin-3-one,

6-(1-benzylpiperidin-4-yl)-4-(4-methoxybenzyl)morpholin-3-one,

7-ethyl-5-(1-isopentylazetidin-3-yl)-4-oxa-7-azaspiro[2.5]octan-8-one,

(2S,6R)-6-(1-benzylpiperidin-4-yl)-4-ethyl-2-methylmorpholin-3-one,

(2S,6S)-6-(1-benzylpiperidin-4-yl)-4-ethyl-2-methylmorpholin-3-one,

(2R,6R)-6-(1-benzylpiperidin-4-yl)-4-ethyl-2-methylmorpholin-3-one,

(2R,6S)-6-(1-benzylpiperidin-4-yl)-4-ethyl-2-methylmorpholin-3-one,

(2S,6R)-4-ethyl-6-(1-(4-fluorobenzyl)piperidin-4-yl)-2-methylmorpholin-3-one,

(2S,6S)-4-ethyl-6-(1-(4-fluorobenzyl)piperidin-4-yl)-2-methylmorpholin-3-one,

(2R,6R)-4-ethyl-6-(1-(4-fluorobenzyl)piperidin-4-yl)-2-methylmorpholin-3-one,

(2R,6S)-4-ethyl-6-(1-(4-fluorobenzyl)piperidin-4-yl)-2-methylmorpholin-3-one,

4-((4-((2R,6S)-4-ethyl-6-methyl-5-oxomorpholin-2-yl)piperidin-1-yl)methyl)benzonitrile,

4-((4-((2S,6S)-4-ethyl-6-methyl-5-oxomorpholin-2-yl)piperidin-1-yl)methyl)benzonitrile,

4-((4-((2R,6R)-4-ethyl-6-methyl-5-oxomorpholin-2-yl)piperidin-1-yl)methyl)benzonitrile,

4-((4-((2S,6R)-4-ethyl-6-methyl-5-oxomorpholin-2-yl)piperidin-1-yl)methyl)benzonitrile,

7-ethyl-5-(1-(4-fluorobenzyl)piperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-8-one,

4-((4-(7-ethyl-8-oxo-4-oxa-7-azaspiro[2.5]octan-5-yl)piperidin-1-yl)methyl)benzonitrile,

5-(1-benzylpiperidin-4-yl)-7-isopropyl-4-oxa-7-azaspiro[2.5]octan-8-one,

5-(1-(4-fluorobenzyl)piperidin-4-yl)-7-isopropyl-4-oxa-7-azaspiro[2.5]octan-8-one,

4-((4-(7-isopropyl-8-oxo-4-oxa-7-azaspiro[2.5]octan-5-yl)piperidin-1-yl)methyl)benzonitrile,

7-ethyl-5-(1-isopentylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-8-one,

6-(1-benzylpiperidin-4-yl)-4-ethylmorpholin-3-one,

5-(1-benzylazetidin-3-yl)-7-ethyl-4-oxa-7-azaspiro[2.5]octan-8-one,

7-ethyl-5-(1-phenethylazetidin-3-yl)-4-oxa-7-azaspiro[2.5]octan-8-one,

5-(1-isopentylpiperidin-4-yl)-7-phenyl-4-oxa-7-azaspiro[2.5]octan-8-one,

5-(1-benzylazetidin-3-yl)-7-phenyl-4-oxa-7-azaspiro[2.5]octan-8-one,

5-(1-isobutylpiperidin-4-yl)-7-(4-methoxybenzyl)-4-oxa-7-azaspiro[2.5]octane,

5-(1-isopentylpiperidin-4-yl)-7-(4-methoxybenzyl)-4-oxa-7-azaspiro[2.5]octane,

7-ethyl-5-(1-isopentylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octane,

2-(1-benzylpiperidin-4-yl)-4-(4-methoxybenzyl)morpholine,

2-(1-benzylpiperidin-4-yl)-4-ethylmorpholine,

(5-(1-Isopentylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-7-yl)(phenyl)methanone,

(R)-5-(1-Benzylpiperidin-4-yl)-7-ethyl-4-oxa-7-azaspiro[2.5]octan-8-one,

(S)-5-(1-benzylpiperidin-4-yl)-7-ethyl-4-oxa-7-azaspiro[2.5]octan-8-one,

(R)-5-(1-Benzylpiperidin-4-yl)-7-ethyl-4-oxa-7-azaspiro[2.5]octane,

(S)-5-(1-benzylpiperidin-4-yl)-7-ethyl-4-oxa-7-azaspiro[2.5]octane,

(R)-(5-(1-Isopentylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-7-yl)(phenyl)methanone,

(S)-(5-(1-isopentylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-7-yl)(phenyl)methanone,

(R)-5-(1-Benzylazetidin-3-yl)-7-phenyl-4-oxa-7-azaspiro[2.5]octan-8-one,

(S)-5-(1-benzylazetidin-3-yl)-7-phenyl-4-oxa-7-azaspiro[2.5]octan-8-one,

(R)-(5-(1-Benzylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-7-yl)(phenyl)methanone and

(S)-(5-(1-benzylpiperidin-4-yl)-4-oxa-7-azaspiro[2.5]octan-7-yl)(phenyl)methanone.

16. A process for the preparation of the compound according to claim 1 , wherein R 1 is —(CR 4 R 4′ ) p R 1′ , which process comprises:

a) the intramolecular cyclization of a compound of formula VII

wherein LG represents a leaving group, including halogen, mesylate, tosylate or triflate, with the proviso that when Y═CO, LG represents chloro or bromo,

or

b) the reaction of a compound of formula VIIIH

with a compound of formula IX, X or XI,

wherein LG represents a leaving group, including halogen, mesylate, tosylate or triflate,

or

c1) when Y is CH 2 , by the alkylation of a compound of formula XIII

with a compound of formula IV

wherein the compound of formula IV is an alkylating agent and W is a leaving group, or alternatively by the reductive amination reaction of a compound of formula XIII with a compound of formula IV, wherein the compound of formula IV is an aldehyde or ketone and W is a C(O)H or C(O) group;

or

c2) when Y is C(O), by the alkylation of a compound of formula XIII

with a compound of formula IV

wherein the compound of formula IV is an alkylating agent and W is a leaving group,

wherein R 1′ , R 2 , R 3 , R 3′ , R 4 , R 4′ , R 5 , R 5′ , R 6 , R 6′ , R 7 , R 8 , R 9 , R 10 , R x , R x′ , X, Y, m, n, p, q and r have the meanings as defined in claim for the compound of Formula (I).

17. A process for the preparation of the compound of Formula (I) according to claim 1 , employing a compound of Formula Ia, II, IIP, III, IIIP, IV, V, VP, VI, VII, VIIP, VIIIP, VIIIH, IX, X, XI, XII, XIIP, XIII, XIIIP, XIIIH, XIV, XIVP, XV, XVP, XVI, XVIP, XVIH, Ib, XVIIP, XVIIH, Ic, XVIIIP, Id, XIXP, XIXH, Ie, XXP, XXH, XXI, XXIP, XXIH, XXII, XXIIP, XXIIH, XXIII, XXIIIP, XXIIIH, XXIV, XXIVP, XXIVH, XXV, XXVP, XXVH, If, XXVIP, XXVIH, XXVIIa, XXVIIb, XXVIIc, Ig, XXVIIIP, XXVIIIH, Ih, XXIXP, XXIXH, Ii, XXXP, XXXH, XXXI, XXXIP, XXXIH, XXXII, XXXIIP, XXXIIH, XXXIII, XXXIIIP, XXXIIIH, XXXIV, XXXIVP, XXXIVH, XXXV, Ij, XXXVIP or XXXVIH,

wherein R 1′ , R 2 , R 3 , R 3′ , R 4 , R 4′ , R 5 , R 5′ , R 6 , R 6′ , R 7 , R 8 , R 9 , R 10 , R x , R x′ , X, Y, m, n, p, q and r have the meanings as defined in claim 1 for the compound of Formula (I), LG represents a leaving group, including halogen, mesylate, tosylate and triflate, with the proviso that when Y═CO, LG represents chloro or bromo, W represents an aldehyde or another leaving group, including halogen, mesylate, tosylate and triflate, P represents a suitable protecting group, including Boc, P′ represents an orthogonal protecting group, including 4-methoxybenzyl and benzyl, Q represents methyl or benzyl, X′ represents a leaving group, including halogen, mesylate, tosylate and triflate, and Z represents OH or halogen, including bromo and chloro.

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

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

20. The method according to claim 19 , wherein the pain is selected from the group consisting of medium to severe pain, visceral pain, chronic pain, cancer pain, migraine, inflammatory pain, acute pain, neuropathic pain, allodynia and hyperalgesia.