Heterocyclic Janus Kinase 3 inhibitors

1. A compound represented by formula (Ia):

wherein

R 1 is hydrogen, or lower alkyl or aryl, each of which may be substituted with one or more substituent(s);

X is a bond, NH or O;

R 4 is cycloalkyl, heterocycloalkyl, lower alkyl, aryl, or heteroaryl, each of which may be substituted with one or more substituent(s);

M is —(CH 2 ) n —, wherein n is an integer of 0 to 4;

R 5 is hydrogen or lower alkyl;

R 6 is hydrogen or lower alkyl which may be substituted with one or more substituent(s);

Y is N or CR 7 , wherein —R 7 is hydrogen, nitro, cyano, amino, acyl or lower alkyl optionally substituted with one substituent selected from the group consisting of heterocycloalkyl and heteroaryl, each of which may be substituted,

or a pharmaceutically acceptable salt thereof.

2. A compound or salt thereof according to claim 1 , wherein

—R 4 is selected from the group consisting of

(1) cycloalkyl optionally substituted with one or more substituent(s) selected from the group consisting of hydroxy, halogen, cyano, protected carboxy, arylalkyloxy, alkyloxy, acyl, carboxamide, aryl, heteroaryl, lower alkyl and lower alkenyl; wherein lower alkyl, lower alkenyl, protected carboxy and carboxamide are optionally substituted with one or more substituent(s);

(2) heterocycloalkyl optionally substituted with one or more substituent(s) selected from the group consisting of lower alkyl, aryl, heteroaryl, cycloalkyl, alkylcarbonyl, alkenylcarbonyl, arylcarbonyl, heteroaryl carbonyl, cycloalkylcarbonyl, heterocycloalkylcarbonyl, alkylsulfonyl, arylsulfonyl, heteroarylsulfonyl, protected carboxy, carbamoyl and sulfamoyl; each of which are optionally substituted with one or more substituent(s); and

(3) lower alkyl optionally substituted with one or more substituent(s) selected from the group consisting of hydroxy, cyano, aryl, heteroaryl, cycloalkyl, heterocycloalkyl, alkyloxy, alkylthio and carboxy, each of which are optionally substituted with one or more substituent(s); and

—R 6 is hydrogen or lower alkyl which may be substituted with one or more cyano, cycloheteroalkyl, aryl, heteroaryl, alkyloxy, heterocycloalkoxy, aryloxy, arylcarbonyl or heteroarylcarbonyl, each of which may be substituted with one or more substituents.

3. A compound or salt thereof according to claim 2 , wherein

—R 4 is selected from the group consisting of

(1) cyclo(lower)alkyl optionally substituted with one or more substituent(s) selected from the group consisting of hydroxy, halogen, cyano, esterified carboxy, arylalkyloxy, alkyloxy, acyl, carboxamide, phenyl and lower alkyl; wherein lower alkyl, alkenyl, esterified carboxy and carboxamide are optionally substituted with one or more substituent(s); and

(2) heterocyclo(lower)alkyl optionally substituted with one or more substituent(s) selected from the group consisting of

(2-1) lower alkyl optionally substituted with one substituent selected from the group consisting of hydroxy, cyano, esterified carboxy, carbamoyl, aryl and heteroaryl;

(2-2) heteroarylcarbonyl, arylcarbonyl, cycloalkylcarbonyl, heterocycloalkylcarbonyl or alkylcarbonyl; each of which may be substituted with one or more substituent(s);

(2-3) heteroarylsulfonyl, arylsulfonyl or alkylsulfonyl; each of which may be substituted with one or more substituent(s) selected from the group consisting of halogen, lower alkyl, cyano and lower alkyloxy;

(2-4) cycloalkyl, heterocycloalkyl, heteroaryl or aryl; each of which may be substituted with one or more substituent(s); and

(2-5) lower alkanoyl, carbamoyl, sulfamoyl, alkylthio, or carboxy; each of which may be substituted one or more substituent(s) selected from the group consisting of lower alkyl, lower alkyl having cyano or alkyloxy, and cycloalkyl.

4. A compound or salt thereof according to claim 3 , wherein

—R 4 is selected from the group consisting of

(1) cyclo(lower)alkyl optionally substituted with one or more substituent(s) selected from the group consisting of hydroxy, halogen, cyano and lower alkyl; and

(2) piperidinyl optionally substituted with one or more substituent(s) selected from the group consisting of

(2-1) methyl optionally substituted with one hydroxy;

(2-2) lower alkanoyl, cyclopropylcarbonyl, thiazolylcarbonyl, thiophenylcarbonyl, pyrrolidinylcarbonyl, piperidinylcarbonyl or azetidinylcarbonyl;

each of which may be substituted with one or more substituent(s) selected from the group consisting of halogen, hydroxy and cyano;

(2-3) lower alkyl sulfonyl;

(2-4) thiazolyl, thienyl, pyridinyl or pyridazinyl; each of which may be substituted with cyano, halogen, nitro, unsubstituted amino and trifluoromethyl; and

(2-5) carbamoyl or sulfamoyl, each of which may be substituted with one or two lower alkyl groups optionally substituted with cyano.

5. A compound which is selected from the group consisting of

(1)1-[(1S,2R)-2-Methylcyclohexyl]-3,6-dihydroimidazo-[4,5-d]pyrrolo[2,3-b]pyridin-2(1H)-one;

(2) 1-[(1S,2R)-2-Ethylcyclohexyl]-3,6-dihydroimidazo[4,5-d]-pyrrolo[2,3-b]pyridin-2(1H)-one hydrochloride;

(3) rel- 1-{(3R,4R)-1-[(5-Chloro-2-thienyl)carbonyl]-4-methyl-3-piperidinyl}-3,6-dihydroimidazo[4,5-d]pyrrolo[2,3-b]-pyridin-2(1H)-one;

(4) rel-1-{[(3R,4R)-4-Methyl-3-(2-oxo-3,6-dihydroimidazo-[4,5-d]pyrrolo[2,3-b]pyridin-1(2H)-yl)-1-piperidinyl]-carbonyl}cyclopropanecarbonitrile;

(5) rel -3-[(3R,4R)-4-Methyl-3-(2-oxo-3,6-dihydroimidazo[4,5-d]-pyrrolo[2,3-b]pyridin-1(2H)-yl)-1-piperidinyl]-3-oxopropanenitrile;

(6) rel -2-[(3R,4R)-4-Methyl-3-(2-oxo-3,6-dihydroimidazo-[4,5-d]pyrrolo[2,3-b]pyridin-1(2H)-yl)-1-piperidinyl]-thiazole-5-carbonitrile;

(7) rel -6-[(3R,4R)-4-Methyl-3-(2-oxo-3,6-dihydroimidazo[4,5-d]-pyrrolo[2,3-b]pyridin-1(2H)-yl)-1-piperidinyl]-3-pyridazinecarbonitrile;

(8) 6-[(3R,4R)-4-Methyl-3-(2-oxo-3,6-dihydroimidazo[4,5-d]-pyrrolo[2,3-b]pyridin-1(2H)-yl)-1-piperidinyl]-nicotinonitrile;

(9) rel-1-{(3R,4R)-1-[(3,3-Difluoro-1-pyrrolidinyl)carbonyl]-4-methyl-3-piperidinyl}-3,6-dihydroimidazo[4,5-d]pyrrolo-[2,3-b]pyridin-2(1H)-one;

(10) rel-1{[(3R,4R)-4-Methyl-3-(2-oxo-3,6-dihydroimidazo-[4,5-d]pyrrolo[2,3-b]pyridin-1(2H)-yl)-1-piperidinyl]-carbonyl }-3-azetidinecarbonitrile;

(11) rel-(3R,4R)—N-(Cyanomethyl)—N,4-dimethyl-3-(2-oxo-3,6-dihydroimidazo[4,5-d]pyrrolo[2,3 -b]pyridin-1(2H)-yl)-1-piperidinecarboxamide;

(12) rel-6-[(3R,4R)-4-Methyl-3-(2-oxo-3,6-dihydroimidazo-[4,5-d]pyrrolo[2,3-b]pyridin-1(2H)-yl)-1-piperidinyl]-nicotinonitrile;

(13) 8-Bromo-1-[(1S,2R)-2-methylcyclohexyl]-3,6-dihydroimidazo[4,5-d]pyrrolo[2,3-b]pyridin-2(1H)-one;

(14) rel-(3R,4R)—N,N,4-Trimethyl-3-(2-oxo-3,6-dihydroimidazo[4,5-d]pyrrolo[2,3-b]pyridin-1(2H)-yl)-piperidine- 1-carboxamide; and

(15) rel-(3R,4R)—N,N,4-trimethyl-3-(2-oxo-3,6-dihydroimidazo [4,5-d]pyrrolo[2,3-b]pyridin-1(2H)-yl)piperidine-1-sulfonamide,

or a pharmaceutically acceptable salt thereof.

6. A pharmaceutical composition which comprises, a compound according to claim 1 and a pharmaceutically acceptable and substantially non-toxic carrier or excipient.