Compositions useful for treating disorders related to kit

1. A compound of Formula II:

or a pharmaceutically acceptable salt thereof, wherein:

Ring A is selected from monocyclic or bicyclic aryl, monocyclic or bicyclic heteroaryl, cycloalkyl, and heterocyclyl;

Z is selected from C 1 -C 6 alkyl, cycloalkyl, monocyclic or bicyclic aryl, monocyclic or bicyclic aralkyl, monocyclic or bicyclic heteroaryl, monocyclic or bicyclic heterocyclyl, and monocyclic or bicyclic heterocyclylalkyl, wherein each of C 1 -C 6 alkyl, cycloalkyl, monocyclic or bicyclic aryl, monocyclic or bicyclic aralkyl, monocyclic or bicyclic heteroaryl, monocyclic or bicyclic heterocyclyl, and monocyclic or bicyclic heterocyclylalkyl is independently substituted with 0-5 occurrences of R C ;

L is selected from a bond, —(C(R 2 )(R 2 )) m —, —(C 2 -C 6 alkynylene)-, —(C 2 -C 6 alkenylene)-, —(C 1 -C 6 haloalkylene)-, —(C 1 -C 6 heteroalkylene)-, —(C 1 -C 6 hydroxyalkylene)-, —C(O)—, —O—, —S—, —S(O), —S(O) 2 —, —N(R 2 )—, —O—(C 1 -C 6 alkylene)-, —(C 1 -C 6 alkylene)-O—, —N(R 2 )—C(O)—, —C(O)—N(R 2 )—, —(C 1 -C 6 alkylene)-N(R 2 )—, —N(R 2 )—(C 1 -C 6 alkylene)-, —N(R 2 )—C(O)—(C 1 -C 6 alkylene)-, —C(O)—N(R 2 )—(C 1 -C 6 alkylene)-, —N(R 2 )—S(O) 2 —, —S(O) 2 —N(R 2 )—, —N(R 2 )—S(O) 2 —(C 1 -C 6 alkylene)-, and —S(O) 2 —N(R 2 )—(C 1 -C 6 alkylene)-;

each R A and R B is independently selected from C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl, C 3 -C 6 heterocyclyl, halo, C 1 -C 6 haloalkyl, C 1 -C 6 hydroxyalkyl, C 1 -C 6 heteroalkyl, monocyclic or bicyclic aralkyl, —N(R 2 )(R 2 ), cyano, and —OR 2 ;

each R C is independently selected from C 1 -C 6 alkyl, C 2 -C 6 alkynyl, halo, C 1 -C 6 heteroalkyl, C 1 -C 6 haloalkyl, C 1 -C 6 haloalkoxy, C 1 -C 6 hydroxyalkyl, cycloalkyl, monocyclic or bicyclic aryl, monocyclic or bicyclic aryloxy, monocyclic or bicyclic aralkyl, monocyclic or bicyclic heterocyclyl, monocyclic or bicyclic heterocyclylalkyl, nitro, cyano, —C(O)R 2 , —OC(O)R 2 , —C(O)OR 2 , —SR 2 , —S(O) 2 R 2 , —S(O) 2 —N(R 2 )(R 2 ), —(C 1 -C 6 alkylene)-S(O) 2 —N(R 2 )(R 2 ), —N(R 2 )(R 2 ), —C(O)—N(R 2 )(R 2 ), —N(R 2 )(R 2 )—C(O)R 2 , —(C 1 -C 6 alkylene)-N(R 2 )—C(O)R 2 , —NR 2 S(O) 2 R 2 , —P(O)(R 2 )(R 2 ), and —OR 2 , wherein each of C 1 -C 6 heteroalkyl, C 1 -C 6 haloalkyl, C 1 -C 6 haloalkoxy, C 1 -C 6 alkyl, C 2 -C 6 alkynyl, cycloalkyl, monocyclic or bicyclic aryl, monocyclic or bicyclic aryloxy, monocyclic or bicyclic aralkyl, monocyclic or bicyclic heterocyclyl, and monocyclic or bicyclic heterocyclylalkyl is independently substituted with 0-5 occurrences of R a ; or 2 R C together with the carbon atom(s) to which they are attached form a cycloalkyl or heterocyclyl ring substituted with 0-5 occurrences of R a ;

each R 2 is independently selected from hydrogen, hydroxyl, halo, thiol, C 1 -C 6 thioalkyl, —NR″R″, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 1 -C 6 haloalkyl, C 1 -C 6 hydroxyalkyl, cycloalkyl, cycloalkylalkyl, heterocyclyl, and heterocyclylalkyl, wherein each of C 1 -C 6 alkyl, cycloalkyl, and heterocyclyl is independently substituted with 0-5 occurrences of R b , or 2 R 2 together with the atoms to which they are attached form a cycloalkyl or heterocyclyl ring;

each R a and R b is independently selected from hydrogen, halo, cyano, hydroxyl, C 1 -C 6 alkoxyl, —C(O)R′, C(O)OR′, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 heteroalkyl, C 1 -C 6 hydroxyalkyl, —NR′R′, and cycloalkyl, wherein cycloalkyl is substituted with 0-5 occurrences of R′;

each R′ is hydrogen, hydroxyl, or C 1 -C 6 alkyl;

each R″ is hydrogen, C 1 -C 6 alkyl, —C(O)—C 1 -C 6 alkyl, —C(O)—NR′R′; or —C(S)—NR′R′; and

m, p, and q are each independently 0, 1, 2, 3, or 4.

2. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein the compound is a compound of Formula III:

3. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein L is —(C(R 2 )(R 2 )) m —.

4. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein A is monocyclic or bicyclic aryl.

5. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein Z is monocyclic or bicyclic aryl.

6. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein Z is monocyclic or bicyclic heteroaryl.

7. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein Z is monocyclic heteroaryl.

8. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein Z is selected from pyrazolyl, isoxazolyl, thiophenyl, thiazolyl, and pyridyl.

9. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein Z is phenyl.

10. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein Z is monocyclic or bicyclic heterocyclyl.

11. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein R A is fluoro and q is 1.

12. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound of claim 1 or a pharmaceutically acceptable salt thereof.

13. A method of treating mastocytosis, the method comprising administering to a patient in need thereof a therapeutically effective amount of a compound of claim 1 or a pharmaceutically acceptable salt thereof.

14. A method of treating gastrointestinal stromal tumor, the method comprising administering to a patient in need thereof a therapeutically effective amount of a compound of claim 1 or a pharmaceutically acceptable salt thereof.

15. A method of treating acute myeloid leukemia, the method comprising administering to a patient in need thereof a therapeutically effective amount of a compound of claim 1 or a pharmaceutically acceptable salt thereof.

16. The method of claim 13 , wherein the mastocytosis is selected from cutaneous mastocytosis (CM) and systemic mastocytosis (SM).

17. The method of claim 16 , wherein the systemic mastocytosis is selected from indolent systemic mastocytosis (ISM), smoldering systemic mastocytosis (SSM), aggressive systemic mastocytosis (ASM), SM with associated hematologic non-mast cell lineage disease (SM-AHNMD), and mast cell leukemia (MCL).

18. The compound of claim 2 or a pharmaceutically acceptable salt thereof, wherein L is —(C(R 2 )(R 2 )) m —.

19. The compound of claim 2 or a pharmaceutically acceptable salt thereof, wherein Z is monocyclic or bicyclic heteroaryl.

20. The compound of claim 2 or a pharmaceutically acceptable salt thereof, wherein R A is fluoro and q is 1.