Pyrazolopyrimidine compounds as adenosine receptor antagonists

1. A compound of formula (I), or pharmaceutically acceptable ester, amide, carbamate, solvate or salt thereof, including a salt of such an ester, amide or carbamate,

wherein R 1 is an optionally substituted phenyl, or an optionally substituted 5- or 6-membered aromatic heterocycle comprising 1, 2 or 3 heteroatoms independently selected from the group consisting of N, S and O, wherein said phenyl is optionally substituted with 1, 2 or 3 substituents, each substituent being independently selected from the group consisting of halogen, OH, C 1-8 alkyl, C 1-8 aklyl substituted with 1, 2 or 3 halogens or OH groups, OC 1-8 alkyl, and OC 1-8 alkyl substituted with 1, 2 or 3 halogens or OH groups, and wherein said 5- or 6-membered aromatic heterocycle is optionally substituted with 1, 2 or 3 substituents, each substituent being independently selected from the group consisting of halogen, OH, C 1-8 alkyl, C 1-8 alkyl substituted with 1, 2 or 3 halogens or OH groups, OC 1-8 alkyl, and OC 1-8 alkyl substituted with 1, 2 or 3 halogens or OH groups; and

R 2 is an optionally substituted 5- or 6-membered aromatic heterocycle comprising 2 or 3 heteroatoms independently selected from the group consisting of N, S and O, wherein said 5- or 6-membered aromatic heterocycle is optionally substituted with 1, 2 or 3 substituents, each substituent being independently selected from the group consisting of C 1-3 alkyl and C 1-3 alkyl substituted with 1, 2 or 3 halogens;

with the proviso that the compound is not selected from the group consisting of

2. A compound as claimed in claim 1 , wherein R 1 is an optionally substituted phenyl, or an optionally substituted 5- or 6-membered aromatic heterocycle comprising 1, 2 or 3 heteroatoms independently selected from the group consisting of N, S and O, wherein said phenyl is optionally substituted with 1, 2 or 3 substituents, each substituent being independently selected from the group consisting of fluorine, meta-chlorine, para-chorine, OH, C 1-8 alkyl, C 1-8 alkyl substituted with 1, 2 or 3 halogens or OH groups, OC 1-8 alkyl, and OC 1-8 alkyl substituted with 1, 2 or 3 halogens or OH groups, and wherein said 5- or 6-membered aromatic heterocycle is optionally substituted with 1, 2 or 3 substituents, each substituent being independently selected from the group consisting of halogen, OH, C 1-8 alkyl, C 1-8 alkyl substituted with 1, 2 or 3 halogens or OH groups, OC 1-8 alkyl, and OC 1-8 alkyl substituted with 1, 2 or 3 halogens or OH groups.

3. A compound as claimed in claim 1 , wherein R 1 is an optionally substituted phenyl, or an optionally substituted 5- or 6-membered aromatic heterocycle comprising 1 or 2 heteroatoms independently selected from the group consisting of N and S.

4. A compound as claimed in claim 1 , wherein when R 1 is a substituted phenyl, said phenyl is substituted with 1, 2 or 3 substituents, each substituent being independently selected from the group consisting of halogen, C 1-8 alkyl, C 1-8 alkyl substituted with 1, 2 or 3 halogens or OH groups, OC 1-8 alkyl, and OC 1-8 alkyl substituted with 1, 2 or 3 halogens.

5. A compound as claimed in claim 1 , wherein when R 1 is a substituted phenyl, said phenyl is substituted with 1 or 2 substituents, each substituent being independently selected from the group consisting of C 1-4 alkyl, C 1-4 alkyl substituted with 1, 2 or 3 halogens or OH groups, OC 1-4 alkyl, and OC 1-4 alkyl substituted with 1, 2 or 3 halogens or OH groups.

6. A compound as claimed in claim 1 , wherein when R 1 is a substituted phenyl, said phenyl is substituted with 1 or 2 substituents, each substituent being independently selected from the group consisting of halogen, C 1-4 alkyl, C 1-4 alkyl substituted with 1, 2 or 3 halogens or OH groups, and OCC 1-8 alkyl.

7. A compound as claimed in claim 1 , wherein R 1 is a substituted phenyl.

8. A compound as claimed claim 1 , wherein R 2 is an optionally substituted 5- or 6-membered aromatic heterocycle comprising 2 or 3 heteroatoms independently selected from the group consisting of N, S and O, wherein at least one of the heteroatoms is N.

9. A compound as claimed in claim 1 , wherein R 2 is an optionally substituted 5- or 6-membered aromatic heterocycle selected from the group consisting of imidazolyl (1,3-diazolyl), pyrazolyl (1,2-diazolyl), 1,3-oxazolyl, isoxazolyl (1,2-oxazolyl), thiazolyl (1,3-thiazolyl), thiazol-2-yl (1,3-thiazol-2-yl), isothiazolyl (1,2-thiazolyl), 2H-1,2,3-triazolyl, 1H-1,2,4-triazolyl, 4H-1,2,4-triazolyl, furazanyl (1,2,5-oxadiazolyl), 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, pyridazinyl (1,2-diazinyl), pyrimidinyl (1,3-diazinyl), pyrazinyl (1,4-diazinyl), 1,2,3-triazinyl, 1,2,4-triazinyl, and 1,3,5-triazinyl.

10. A compound as claimed in claim 1 , wherein R 2 is an optionally substituted 5- or 6-membered aromatic heterocycle, and wherein said 5- or 6-membered aromatic heterocycle is optionally substituted with 1 or 2 substituents, each substituent being independently selected from the group consisting of C 1-3 alkyl and C 1-3 alkyl substituted with 1, 2 or 3 fluorines.

11. A compound as claimed in claim 1 , wherein the compound is selected from the group consisting of

2-[(3-methylphenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-methoxyphenyl)methyl]-6-(pyrazin-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

3-{[4-amino-6-(pyrazin-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-2-yl]methyl}phenol;

2-[(3-methoxyphenyl)methyl]-6-(1,3-oxazol-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-methoxyphenyl)methyl]-6-(4-methyl-1,3-thiazol-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-methoxyphenyl)methyl]-6-(3-methyl-1,2-oxazol-5-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-methoxyphenyl)methyl]-6-(4-methyl-1,2,3-thiadiazol-5-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-methoxyphenyl)methyl]-6-(1,3-thiazol-1-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-methoxyphenyl)methyl]-6-(1,3-thiazol-4-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-methoxyphenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-methoxyphenyl)methyl]-6-(1,3-oxazol-5-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(4-methyl phenyl)methyl]-6-(pyrazin-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(4-methylphenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(4-methylphenyl)methyl]-6-(1,3-thiazol-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(4-methoxyphenyl)methyl]-(4pyrazin-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

6-(1,2-thiazol-3-yl)-2-{[3-(trifluoromethoxy)phenyl]methyl}-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

6-(1,2-thiazol-3-yl)-2-{[4-(trifluoromethyl)phenyl]methyl}-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-methoxy-4-methylphenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-fluoro-4-methylphenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(2,5-dichlorophenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3,4-dimethylphenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(pyridin-2-yl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(6-methylpyridin-3-yl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-{[4-methyl-3-(trifluoromethyl)phenyl]methyl}-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(2-methoxy-4-methylphenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-methylphenyl)methyl]-6-(1,3-oxazol-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-methylphenyl)methyl]-64pyrazin-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

64pyrazin-2-yl)-2-{[3-(trifluoromethyl)phenyl]methyl}-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-fluorophenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-fluorophenylmethyl]-64pyrazin-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(2-methylphenyl)methyl]-64pyrazin-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(2-methylphenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

6-(1,3-thiazol-2-yl)-2-[(1,3-thiazol-2-yl)methyl]-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(1,3-thiazol-2-yl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-chlorophenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3-chlorophenyl)methyl]-6-(pyrazin-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(2-methoxyphenyl)methyl]-6-(pyrazin-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(2-methoxyphenyl)methyl]-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(2-methoxyphenyl)methyl]-6-(1,3-oxazol-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(2-methoxyphenyl)methyl]-6-(1,3-oxazol-5-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

2-[(3,4-dimethoxyphenyl)methyl]-6-(pyrazin-2-yl)-2H-pyrazolo[3,4-d]pyrimidin-4-amine;

3-{[4-amino-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-2-yl]methyl}phenol;

2-{[4-amino-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-2-yl]methyl}-5-meth phenol;

2-{[4-amino-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-2-yl]methyl}phenol;

5-{[4-amino-6-(1,2-thiazol-3-yl)-2H-pyrazolo[3,4-d]pyrimidin-2-yl]methyl}-2-methyl phenol; and

[3-[(4-amino-6-(1,2-thiazol-3-yl)-pyrazolo[3,4-d]pyrimidin-2-yl)methyl]phenyl]methanol;

or pharmaceutically acceptable ester, amide, carbamate, solvate or salt thereof, including a salt of such an ester, amide or carbamate.

12. A pharmaceutical composition which comprises a compound claimed in claim 1 , together with a pharmaceutically suitable carrier, and optionally also comprises a further therapeutic agent.

13. A diagnostic agent for the diagnosis of a disease or disorder associated with the adenosine 2a receptor, comprising the compound of claim 1 in labelled form.

14. A method for the treatment of a disease or disorder associated with the adenosine 2a receptor in a mammal, which comprises administering to the mammal a therapeutically effective amount of a compound as claimed in claim 1 .

15. The method as claimed in claim 14 , wherein the disease or disorder associated with the adenosine 2a receptor is a disease or disorder selected from the group consisting of cancer, neurodegenerative diseases, retinal degenerative diseases, insomnia, pain, psychiatric diseases, ischemia, infarction, acute inflammatory diseases, chronic inflammatory diseases, spinal cord injury, and epilepsy.

16. The method as claimed in claim 14 , wherein the disease or disorder associated with the adenosine 2a receptor is cancer, and wherein the cancer is selected from the group consisting of lymphoma, sarcoma, bladder cancer, bone cancer, brain tumor, cervical cancer, renal cell cancer, colorectal cancer, esophageal cancer, gastric cancer, head and neck cancer, kidney cancer, myeloma, thyroid cancer, leukaemia, breast cancer, ovarian cancer, pancreatic cancer, liver cancer, lung cancer, glioblastoma multiforme, glioma, melanoma, prostate cancer, glioblastoma, squamous cell carcinoma, multiple myeloma, skin cancer, testicular cancer, neuroblastoma and metastatic cancer.

17. A method for identifying ligands for the adenosine 2a receptor, wherein a compound of claim 1 in labelled form is the reference compound.

18. A method for the treatment or prophylaxis of a disease or disorder associated with the adenosine 2a receptor in a mammal, which comprises administering to the mammal a therapeutically effective amount of the pharmaceutical composition of claim 12 .

19. The method of claim 18 , wherein the disease or disorder associated with the adenosine 2a receptor is a disease or disorder selected from the group consisting of cancer, neurodegenerative diseases, retinal degenerative diseases, insomnia, pain, psychiatric diseases, ischemia, infarction, acute inflammatory diseases, chronic inflammatory diseases, spinal cord injury, and epilepsy.

20. The method of claim 18 , wherein the disease or disorder associated with the adenosine 2a receptor is cancer, and wherein the cancer is selected from the group consisting of lymphoma, sarcoma, bladder cancer, bone cancer, brain tumor, cervical cancer, renal cell cancer, colorectal cancer, esophageal cancer, gastric cancer, head and neck cancer, kidney cancer, myeloma, thyroid cancer, leukaemia, breast cancer, ovarian cancer, pancreatic cancer, liver cancer, lung cancer, glioblastoma multiforme, glioma, melanoma, prostate cancer, glioblastoma, squamous cell carcinoma, multiple myeloma, skin cancer, testicular cancer, neuroblastoma and metastatic cancer.

21. The method as claimed in claim 16 , wherein the cancer is renal cell cancer or lung cancer.

22. The method as claimed in claim 16 , wherein the therapeutically effective amount of the compound is administered as an oral dosage.

23. The method as claimed in claim 16 , wherein the compound is administered simultaneously, sequentially, or separately with one or more further therapeutic agent(s).

24. The method as claimed in claim 23 , wherein the further therapeutic agent is a checkpoint inhibitor.

25. The method of claim 18 , wherein the cancer is renal cell cancer or lung cancer.

26. The method as claimed in claim 18 , wherein the therapeutically effective amount of the pharmaceutical composition is administered as an oral dosage.

27. The method as claimed in claim 18 , wherein the pharmaceutical composition is administered simultaneously, sequentially or separately with one or more further therapeutic agent(s).

28. The method as claimed in claim 27 , wherein the further therapeutic agent is a checkpoint inhibitor.