Therapeutic compounds and compositions, and methods of use thereof

1. A compound of Formula (I)

or a pharmaceutically acceptable salt or stereoisomer thereof, wherein:

R 1 is hydrogen or CH 3 ;

R 2 is halogen, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 3 -C 6 cycloalkyl, or —OR a , wherein R 2 is optionally substituted by one or more groups independently selected from the group consisting of halogen, C 1 -C 3 alkyl, cyano, hydroxy and oxo;

R a is C 1 -C 6 alkyl, -phenyl-COR b R c , -phenyl-(3-6-membered heterocyclyl), or 3-11-membered heterocyclyl, wherein R a is optionally substituted by one or more groups independently selected from the group consisting of halogen, C 1 -C 3 alkyl, cyano, hydroxy and oxo;

R b and R c are each independently hydrogen or CH 3 ;

R 3 is hydrogen or NH 2 ;

R 4 is hydrogen or CH 3 ; and

R 5 is hydrogen or NH 2 .

2. The compound of claim 1 or a pharmaceutically acceptable salt or stereoisomer thereof, wherein R 1 is hydrogen.

3. The compound of claim 1 or a pharmaceutically acceptable salt or stereoisomer thereof, wherein R 1 is CH 3 .

4. The compound of claim 1 or a pharmaceutically acceptable salt or stereoisomer thereof, wherein R 3 is hydrogen.

5. The compound of claim 1 or a pharmaceutically acceptable salt or stereoisomer thereof, wherein R 4 and R 5 are each hydrogen.

6. The compound of claim 1 or a pharmaceutically acceptable salt or stereoisomer thereof, wherein R 1 , R 3 , R 4 and R 5 are each hydrogen.

7. The compound of claim 1 or a pharmaceutically acceptable salt or stereoisomer thereof, wherein R2 is C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 3 -C 6 cycloalkyl, or —OR a , wherein R 2 is optionally substituted by one or more groups independently selected from the group consisting of halogen, C 1 -C 3 alkyl, cyano, hydroxy and oxo.

8. The compound of claim 1 or a pharmaceutically acceptable salt or stereoisomer thereof, wherein R 2 is selected from the group consisting of halogen, C 1 -C 6 haloalkyl and C 1 -C 6 haloalkoxy.

9. The compound of claim 1 or a pharmaceutically acceptable salt or stereoisomer thereof, wherein R 2 is selected from the group consisting of

10. A compound selected from the group consisting of 1-18 below:

or a pharmaceutically acceptable salt or stereoisomer thereof.

11. A compound which is:

or a pharmaceutically acceptable salt thereof.

12. A compound which is:

or a pharmaceutically acceptable salt thereof.

13. A compound which is:

or a pharmaceutically acceptable salt thereof.

14. A compound which is:

or a pharmaceutically acceptable salt or stereoisomer thereof.

15. A compound which is:

or a pharmaceutically acceptable salt thereof.

16. A compound which is:

or a pharmaceutically acceptable salt or stereoisomer thereof.

17. A compound which is:

or a pharmaceutically acceptable salt thereof.

18. A compound which is:

or a pharmaceutically acceptable salt thereof.

19. A compound which is:

or a pharmaceutically acceptable salt or stereoisomer thereof.

20. A compound which is:

or a pharmaceutically acceptable salt or stereoisomer thereof.

21. A compound which is:

or a pharmaceutically acceptable salt thereof.

22. A compound which is:

or a pharmaceutically acceptable salt thereof.

23. A compound which is:

or a pharmaceutically acceptable salt thereof.

24. A compound which is:

or a pharmaceutically acceptable salt thereof.

25. A compound which is:

or a pharmaceutically acceptable salt thereof.

26. A compound which is:

or a pharmaceutically acceptable salt thereof.

27. A pharmaceutical composition comprising a compound of claim 1 or a pharmaceutically acceptable salt or stereoisomer thereof, and a pharmaceutically acceptable carrier, diluent or excipient.

28. A method of treating or lessening the severity of a disease or condition responsive to the inhibition of a Janus kinase activity in a patient, wherein the disease or condition is asthma, comprising administering to the patient a therapeutically effective amount of a compound of claim 1 or a stereoisomer or pharmaceutically acceptable salt thereof.

29. The method of claim 28 , wherein the Janus kinase is JAK1.