Melanocortin receptor ligands modified with hydantoin

1. A compound of formula

wherein:

X is selected from the group consisting of —CH 2 —S—S—CH 2 —, —C(CH 3 ) 2 —S—S—CH 2 —, —CH 2 —S—S—C(CH 3 ) 2 —S—S—C(CH 3 ) 2 —, —(CH 2 ) 2 —S—S—CH 2 —, —CH 2 —S—S—(CH 2 ) 2 —, —(CH 2 ) 2 —S—S—(CH 2 ) 2 —, —C(CH 3 ) 2 —S—S—(CH 2 ) 2 —, —(CH 2 ) 2 —S—S—C(CH 3 ) 2 , —(CH 2 ) t —C(O)—NR 8 —(CH 2 ) r — and —(CH 2 )r-NR 8 —C(O)—(CH 2 ) t —;

R 1 and R 2 each is, independently for each occurrence thereof, H, (C 1 -C 10 )alkyl or substituted (C 1 -C 10 )alkyl;

R 3 is —OH or —NH 2 ;

R 4 and R 5 each is, independently for each occurrence thereof, H, (C 1 -C 10 )alkyl or substituted (C 1 -C 10 )alkyl;

X 1 is

A 1 is His, 2-Pal, 3-Pal, 4-Pal, Tar, 2-Thi, 3-Thi, Phe or deleted;

A 2 is D-Bal, D-1-Nal, D-2-Nal, D-Phe or D-Phe;

A 3 is Arg, hArg, Dab, Dap, Lys or Orn;

A 4 is Bal, 1-Nal, 2-Nal, Phe or Trp;

R 6 and R 7 each is, independently for each occurrence thereof, H, (C 1 -C 10 )alkyl, (C 1 -C 10 )heteroalkyl, aryl(C 1 -C 5 )alkyl, substituted (C 1 -C 10 )alkyl, substituted (C 1 -C 10 )heteroalkyl or substituted aryl(C 1 -C 5 )alkyl or R 6 and R 7 may be joined together form a cyclic moiety;

R 8 is H, (C 1 -C 10 )alkyl or substituted (C 1 -C 10 )alkyl;

r is, independently for each occurrence thereof, 1, 2, 3, 4 or 5; and

t is, independently for each occurrence thereof, 1 or 2;

or a pharmaceutically acceptable salt thereof.

2. A compound according to claim 1 , wherein said compound is a selective melanocortin-4 receptor agonist.

3. A compound according claim 1 wherein said compound is

cyclo[Hydantoin(C(O)-(hCys-D-Ala))-His-D-2-Nal-Arg-Trp-Cys]-NH 2 ; or

cyclo[Hydantoin(C(O)-(Glu-His))-D-Phe-Arg-Trp-Dap]-NH 2 ;

or a pharmaceutically acceptable salt thereof.

4. A compound according to claim 1 wherein said compound is

cyclo[Hydantoin(C(O)-(Asp-A6c))-D-2-Nal-Arg-Trp-Lys]-NH 2 ;

or a pharmaceutically acceptable salt thereof.

5. A compound according to claim 1 wherein said compound is

cyclo[Hydantoin(C(O)-(Asp-Aic))-D-2-Nal-Arg-Trp-Lys]-NH 2 ;

or a pharmaceutically acceptable salt thereof.

6. A compound according to claim 1 wherein said compound is

cyclo[Hydantoin(C(O)-(Glu-D-Ala))-His-D-Phe-Arg-Trp-Dap]-NH 2 ;

or a pharmaceutically acceptable salt thereof.

7. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to claim 1 or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or diluent.

8. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to claim 2 or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or diluent.

9. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to claim 3 or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or diluent.

10. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to claim 4 or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or diluent.

11. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to claim 5 or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or diluent.

12. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to claim 6 or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or diluent.

13. A method of treating a disease or medical condition in a subject in need of such treatment, comprising administering to said subject a compound according to claim 2 , wherein said disease or condition is selected from the group consisting of:

general inflammation, inflammatory bowel disease, brain inflammation, sepsis and septic shock;

rheumatoid arthritis, gouty arthritis and multiple sclerosis;

a metabolic disease or medical condition accompanied by weight loss, anorexia, bulimia, AIDS wasting, cachexia, cancer cachexia and wasting in frail elderly;

skin cancer and cancer cachexia;

endometriosis, uterine bleeding, sexual dysfunction, erectile dysfunction and decreased sexual response in females;

organ transplant rejection, ischemia and reperfusion injury, wounding and spinal cord injury, and weight loss due to a medical procedure selected from the group consisting of chemotherapy, radiation therapy, temporary or permanent immobilization and dialysis;

hemorrhagic shock, cardiogenic shock, hypovolemic shock, cardiovascular disorders and cardiac cachexia;

acute respiratory distress syndrome, pulmonary fibrosis, chronic obstructive pulmonary disease and asthma;

enhanced immune tolerance;

allergies;

psoriasis, skin pigmentation depletion, acne and keloid formation;

anxiety, depression, memory dysfunction and neuropathic pain; and

renal cachexia and natriuresis.

14. The method according to claim 13 , wherein cyclo[Hydantoin(C(O)-(Glu-D-Ala))-His-D-Phe-Arg-Trp-Dap]-NH 2 ; or a pharmaceutically acceptable salt thereof is administered.

15. A method of treating a disease or medical condition in a subject in need of such treatment, comprising administering to said subject a compound according to claim 2 , wherein said disease or condition is selected from the group consisting of:

a metabolic disease or medical condition accompanied by weight gain, obesity, feeding disorders and Prader-Willi Syndrome;

diabetes, diabetalogical related conditions and complications of diabetes such as retinopathy.

16. The method according to claim 15 , wherein cyclo[Hydantoin(C(O)-(Glu-D-Ala))-His-D-Phe-Arg-Trp-Dap]-NH 2 ; or a pharmaceutically acceptable salt thereof is administered.

17. The method according to claim 15 , wherein obesity is treated.

18. The method according to claim 15 , wherein body weight is decreased.

19. The method according to claim 15 , wherein diabetes is treated.

20. The method according to claim 16 , wherein diabetes is treated.

21. The method according to claim 15 , wherein complications of diabetes are treated.

22. The method according to claim 16 , wherein complications of diabetes are treated.

23. A method of modulating ovarian weight, placental development, prolactin secretion, FSH secretion, intrauterine fetal growth, parturition, spermatogenesis, thyroxin release, aldosterone synthesis and release, body temperature, blood pressure, heart rate, vascular tone, brain blood flow, blood glucose levels, sebum secretion, pheromone secretion, motivation, learning and behavior, pain perception, neuroprotection, nerve growth, bone metabolism, bone formation and bone development in a subject, comprising administering to said subject a compound according to claim 1 .

24. The method according to claim 23 , wherein cyclo[Hydantoin(C(O)-(Glu-D-Ala))-His-D-Phe-Arg-Trp-Dap]-NH 2 , or a pharmaceutically acceptable salt thereof, is administered.

25. A method of inhibiting alcohol consumption, reducing alcohol consumption, treating alcoholism, or treating alcohol abuse in a subject, comprising administering to said subject a therapeutically effective amount of a compound according to claim 1 , or a pharmaceutically acceptable salt thereof.

26. The method according to claim 25 , wherein cyclo[Hydantoin(C(O)-(Glu-D-Ala))-His-D-Phe-Arg-Trp-Dap]-NH 2 , or a pharmaceutically acceptable salt thereof, is administered.