Bicyclic analgesic compounds

1. A method for reducing pain comprising administering an effective amount of a compound of Formula (I), or a pharmaceutically acceptable salt thereof, wherein Formula (I) has the structure:

wherein:

R 1 is H, —CH 3 or an unsubstituted (C 2 to C 5 ) alkyl;

R 2 is H or —C(═Y)R 4 ;

R 3 is a substituted or unsubstituted (C 1 to C 30 ) alkyl, a substituted or unsubstituted (C 2 to C 30 ) alkenyl, a substituted or unsubstituted (C 3 to C 30 ) cycloalkyl, a substituted or unsubstituted (C 3 to C 30 ) cycloalkenyl, a substituted or unsubstituted (C 8 to C 30 ) cycloalkynyl, a substituted or unsubstituted (C 6 to C 30 ) aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted heterocyclyl, a substituted or unsubstituted aryl(C 1-6 alkyl), or a substituted or unsubstituted heteroaryl(C 1-6 alkyl);

R 4 is a substituted or unsubstituted (C 1 to C 10 ) alkyl; and

Y is O.

2. The method of claim 1 , further comprising administering an opioid analgesic.

3. The method of claim 2 , wherein the opioid analgesic is selected from the group consisting of codeine, hydrocodone and oxycodone.

4. The method of claim 1 , wherein the administration is intravenous.

5. The method of claim 1 , wherein the administration is oral.

6. The method of claim 1 , wherein the pain is acute pain.

7. The method of claim 1 , wherein R 2 is H.

8. The method of claim 7 , wherein R 1 is H.

9. The method of claim 1 , wherein R 3 is a substituted or unsubstituted (C 6 to C 30 ) aryl.

10. The method of claim 1 , wherein R 3 is a substituted or unsubstituted heteroaryl.

11. The method of claim 1 , wherein R 3 is a substituted or unsubstituted heterocyclyl.

12. The method of claim 1 , wherein R 3 is a substituted or unsubstituted aryl(C 1-6 alkyl) or a substituted or unsubstituted heteroaryl(C 1-6 alkyl).

13. A compound of Formula (I), or a pharmaceutically acceptable salt thereof:

wherein:

R 1 is H, —CH 3 or an unsubstituted (C 2 to C 5 ) alkyl;

R 2 is —C(═Y)R 4 ; and

R 3 is a substituted or unsubstituted (C 1 to C 30 ) alkyl, a substituted or unsubstituted (C 2 to C 30 ) alkenyl, a substituted or unsubstituted (C 3 to C 30 ) cycloalkyl, a substituted or unsubstituted (C 3 to C 30 ) cycloalkenyl, a substituted or unsubstituted (C 8 to C 30 ) cycloalkynyl, a substituted or unsubstituted (C 6 to C 30 ) aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted heterocyclyl, or a substituted or unsubstituted aryl(C 1-6 alkyl); or

R 1 is H, —CH 3 , —CF 3 , or a substituted or unsubstituted (C 2 to C 5 ) alkyl;

R 2 is H; and

R 3 is a substituted or unsubstituted (C 3 to C 30 ) cycloalkyl, a substituted or unsubstituted (C 3 to C 30 ) cycloalkenyl, a substituted or unsubstituted (C 8 to C 30 ) cycloalkynyl, a substituted (C 6 to C 30 ) aryl, an unsubstituted (C 7 to C 30 ) aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted heterocyclyl, a substituted or unsubstituted aryl(C 1-6 alkyl), a substituted or unsubstituted heteroaryl(C 1-6 alkyl);

R 4 is or a substituted or unsubstituted (C 1 to C 10 ) alkyl; and

Y is or O.

14. The compound of claim 13 , wherein R 2 is H.

15. The compound of claim 14 , wherein R 1 is H.

16. The compound of claim 13 , wherein R 3 is a substituted (C 6 to C 30 ) aryl.

17. The compound of claim 13 , wherein R 3 is a substituted or unsubstituted heteroaryl.

18. The compound of claim 13 , wherein R 3 is a substituted or unsubstituted heterocyclyl.

19. The compound of claim 13 , wherein R 3 is a substituted or unsubstituted aryl(C 1-6 alkyl) or a substituted or unsubstituted heteroaryl(C 1-6 alkyl).

20. A pharmaceutical composition comprising an effective amount of a compound of claim 13 , or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, diluent, excipient or combination thereof.

21. The method of claim 1 , wherein the pain is chronic pain.

22. The method of claim 1 , wherein the administration is intramuscular.