Bicyclic heteroaryl cycloalkyldiamine derivatives

1. A compound of the formula (I) or a pharmaceutically acceptable salt thereof,

wherein

X1 is CR1;

X2 is CH;

Y is CH 2 or O;

A is bicyclic hetereoaryl having from 8 to 10 ring atoms, wherein 1-3 of said ring atoms are heteroatoms selected from N, O and S and wherein said heteroaryl may be unsubstituted of substituted at a carbon atom by a R2 or at a nitrogen atom by a R3;

R1 is H, Hal or C 1-4 alkyl;

R2 is H, C 1-4 alkyl, C 3-5 cycloalkyl, CN or Hal; and

R3 is H or alkyl.

2. A compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein

X1 is CH;

X2 is CH;

Y is CH 2 ;

A is bicyclic hetereoaryl having from 8 to 10 ring atoms, wherein 1-2 of said ring atoms are heteroatoms selected from N, O and S and wherein said heteroaryl may be unsubstituted of substituted at a carbon atom by a R2 and at a nitrogen atom by a R3;

R2 is H, C 1-4 alkyl, C 3-5 cycloalkyl, CN or Hal; and

R3 is H or alkyl.

3. A compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein

X1 is CH;

X2 is CH;

Y is CH 2 ;

A is an unsubstituted or substituted indole moiety, wherein the substituent is R2 and is attached to a carbon atom of the indole moiety; wherein

R2 is C 1-4 alkyl.

4. A compound of claim 1 , which is a compound of formula (II) or a pharmaceutically acceptable salt thereof, wherein

Y is CH 2 or 0; and

R2 is H, C 1-4 alkyl or Hal.

5. A compound of claim 4 , or a pharmaceutically acceptable salt thereof, wherein

Y is CH 2 ; and

R2 is H, or C 1-4 alkyl or Hal.

6. A compound of claim 1 , or a pharmaceutically acceptable salt thereof, which is selected from:

7-((1R,2S)-2-Amino-cyclohexylamino)-8-fluoro-5-(5-fluoro-3-methyl-1H-indol-7-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-8-fluoro-5-(quinolin-5-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(3-methyl-1H-indol-7-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(1-methyl-1H-indol-4-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(2-methyl-2H-indazol-4-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(5-fluoro-3-methyl-1H-indol-7-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(quinolin-6-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(benzofuran-4-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(benzo[b]thiophen-4-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(2-methyl-quinolin-5-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(1H-indol-4-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(1H-indazol-4-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(quinolin-3-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(1H-indol-7-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(8-methyl-quinolin-5-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-[7-((1R,2S)-2-Amino-cyclohexylamino)-4-oxo-3,4-dihydro-pyrido[3,4-d]pyridazin-5-ylamino]-1H-indole-3-carbonitrile,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(7-methyl-1H-indol-4-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(quinolin-5-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(2-methyl-1H-indol-4-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(quinoxalin-6-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(quinolin-7-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((1R,2S)-2-Amino-cyclohexylamino)-5-(quinolin-8-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((3R,4R)-3-Amino-tetrahydro-pyran-4-ylamino)-5-(3-methyl-1H-indol-7-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((3R,4R)-3-Amino-tetrahydro-pyran-4-ylamino)-5-(benzo[b]thiophen-4-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one,

7-((3R,4R)-3-Amino-tetrahydro-pyran-4-ylamino)-5-(5-fluoro-3-methyl-1H-indol-7-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one, and

7-((3R,4R)-3-Amino-tetrahydro-pyran-4-ylamino)-5-(1H-indol-7-ylamino)-3H-pyrido[3,4-d]pyridazin-4-one.

7. A pharmaceutical composition comprising a therapeutically effective amount of a compound according to claim 1 or a pharmaceutically acceptable salt thereof and one or more pharmaceutically acceptable carriers.

8. A combination comprising a therapeutically effective amount of a compound according to claim 1 or a pharmaceutically acceptable salt thereof and one or more therapeutically active co-agents.

9. A method of modulating SYK activity in a subject, wherein the method comprises administering to the subject a therapeutically effective amount of the compound according to claim 1 .