Potassium channel modulators

1. A compound of formula (I-a)

or a pharmaceutically acceptable salt thereof, wherein

R 1 is —(CR 1a R 1b ) n -G 1a

R 1a , at each occurrence, is independently hydrogen, alkyl, halogen, or haloalkyl;

R 1b , at each occurrence, is independently hydrogen, alkyl, halogen, haloalkyl, OR y , N(R y ) 2 , S(R y ), C(O)OR y , C(O)R y , C(O)N(R y ) 2 , —(C 1 -C 6 alkylenyl)OR y , —(C 1 -C 6 alkylenyl)N(R y ) 2 , —(C 1 -C 6 alkylenyl)S(R y ), —(C 1 -C 6 alkylenyl)C(O)OR y , —(C 1 -C 6 alkylenyl)C(O)R y , or —(C 1 -C 6 alkylenyl)C(O)N(R y ) 2 ;

R y , at each occurrence, is independently hydrogen, alkyl, or haloalkyl;

G 1a , at each occurrence, is independently aryl, heteroaryl, heterocycle, cycloalkenyl, or cycloalkyl; each of which is independently unsubstituted or substituted with 1, 2, 3, 4, or 5 substituents as represented by R 101 ;

R 2 is —OR 2ac , —SR 2bc , —S(O)R 2bc , —S(O) 2 R 2bc , —S(O) 2 N(R 2d )(R 2e ), —C(O)R 2cc , —C(O)OR 2cc , —C(O)N(R 2d )(R 2e ), N(R 2d )(R 2e ), —C(R 2d )═NOR 2dc , G 2a , —(CR 2a R 2b ) p -G 2a , —(CR 2a R 2b ) p —OR 2ac , —(CR 2a R 2b ) p —SR 2bc , —(CR 2a R 2b ) p —S(O)R 2bc , —(CR 2a R 2b ) p —C(O)R 2cc , —(CR 2a R 2b ) p —C(O)OR 2cc , —(CR 2a R 2b ) p —C(O)N(R 2d )(R 2e ), —(CR 2a R 2b ) p —N(R 2d )(R 2e ), or —(CR 2a R 2b ) p —S(O) 2 N(R 2d )(R 2e ), —(CR 2a R 2b ) p —S(O) 2 R 2bc ;

R 2a and R 2b , at each occurrence, are each independently hydrogen, alkyl, haloalkyl, —C(O)OR 2aa , G 2b , or —(C 1 -C 6 alkylenyl)-G 2b ;

R 2aa , at each occurrence, is independently hydrogen, alkyl, haloalkyl, G 2b , or —(C 1 -C 6 alkylenyl)-G 2b ;

R 2ac , R 2bc , R 2cc , R 2dc , and R 2d , at each occurrence, are each independently hydrogen, alkyl, haloalkyl, G 2c , or —(C 1 -C 6 alkylenyl)-G 2c ;

R 2e , at each occurrence, is independently hydrogen, alkyl, haloalkyl, -alkylenyl-alkoxy, -alkylenyl-haloalkoxy, —C(O)R 2f , —C(O)OR 2f , S(O) 2 R 2f , —C(O)NR 2f R 2g , —C(O)—(C 1 -C 6 alkylenyl)NR 2fg R 2g , or -alkylenyl-CN;

R 2f , at each occurrence, is independently hydrogen, alkyl, haloalkyl, G 2d , or —(C 1 -C 6 alkylenyl)-G 2d ;

R 2fg , at each occurrence, is independently hydrogen, alkyl, haloalkyl, —C(O)OR 2h , G 2d , or —(C 1 -C 6 alkylenyl)-G 2d ;

R 2g and R 2h , at each occurrence, are each independently hydrogen, alkyl, or haloalkyl,

G 2a , at each occurrence, is independently heteroaryl or heterocycle; each of which is optionally substituted with 1, 2, 3, 4, or 5 R 102 groups;

G 2b , G 2c , and G 2d , at each occurrence, are each independently aryl, heteroaryl, heterocycle, cycloalkyl, or cycloalkenyl; each of which is optionally substituted with 1, 2, 3, 4, or 5 R 103 groups;

T, R 101 , R 102 , and R 103 , at each occurrence, are each independently G a , alkyl, alkenyl, alkynyl, halogen, haloalkyl, oxo, —CN, —NO 2 , —OR a , —OC(O)R a , —OC(O)NR a R b , —NR a R b , —SR a , —S(O)R a , —S(O) 2 R a , —S(O) 2 NR a R b , —C(O)R a , —C(O)OR a , —C(O)NR a R b , —N(R a )C(O)OR b , —N(R a )C(O)NR a R b , —N(R a )S(O) 2 NR a R b , —(CR za R zb ) m —CN, —(CR za R zb ) m —NO 2 , —(CR za R zb ) m —OR a , —(CR za R zb ) m —OC(O)R a , —(CR za R zb ) m —OC(O)NR a R b , —(CR za R zb ) m —SR a , —(CR za R zb ) m —S(O)R a , —(CR za R zb ) m —S(O) 2 R a , —(CR za R zb ) m —S(O) 2 NR a R b , —(CR za R zb ) m —C(O)R a , —(CR za R zb ) m —C(O)OR a , —(CR za R zb ) m —C(O)NR a R b , —(CR za R zb ) m —NR a R b , —(CR za R zb ) m —N(R a )C(O)OR b , —(CR za R zb ) m —N(R a )C(O)NR a R b , —(CR za R zb ) m —N(R a )S(O) 2 NR a R b , or —(CR za R zb ) m -G a ;

R a and R b , at each occurrence, are each independently hydrogen, alkyl, haloalkyl, G a , or —(C 1 -C 6 alkylenyl)-G a ;

G a , at each occurrence, is independently aryl, heteroaryl, heterocycle, cycloalkyl or cycloalkenyl, each of which is independently unsubstituted or substituted with 1, 2, 3, 4, or 5 substituents independently selected from the group consisting of alkyl, alkenyl, alkynyl, halogen, haloalkyl, oxo, —CN, —NO 2 , —OR a′ , —OC(O)R a′ , —OC(O)NR a′ R b′ , —NR a′ R b′ , —SR a′ , —S(O)R a′ , —S(O) 2 R a′ , —S(O) 2 NR a′ R b′ , —C(O)R a′ , —C(O)OR a′ , —C(O)NR a′ R b′ , —N(R a′ )C(O)OR b′ , —N(R a′ )C(O)NR a′ R b′ , —N(R a′ )S(O) 2 NR a′ R b′ , —(C 1 -C 6 alkylenyl)-CN, —(C 1 -C 6 alkylenyl)-NO 2 , —(C 1 -C 6 alkylenyl)-OR a′ , —(C 1 -C 6 alkylenyl)-OC(O)R a′ , —(C 1 -C 6 alkylenyl)-OC(O)NR a′ R b′ , —(C 1 -C 6 alkylenyl)-SR a′ , —(C 1 -C 6 alkylenyl)-S(O)R a′ , —(C 1 -C 6 alkylenyl)-S(O) 2 R a′ , —(C 1 -C 6 alkylenyl)-S(O) 2 NR a′ R b′ , —(C 1 -C 6 alkylenyl)-C(O)R a′ , —(C 1 -C 6 alkylenyl)-C(O)OR a′ , —(C 1 -C 6 alkylenyl)-C(O)NR a′ R b′ , —(C 1 -C 6 alkylenyl)-NR a′ R b′ , —(C 1 -C 6 alkylenyl)-N(R a′ )C(O)OR b′ , —(C 1 -C 6 alkylenyl)-N(R a′ )C(O)NR a′ R b′ , and —(C 1 -C 6 alkylenyl)-N(R a′ )S(O) 2 NR a′ R b′ ;

R za , R zb , R a′ , and R b′ , at each occurrence, are each independently hydrogen, alkyl, halogen, or haloalkyl;

m, n, and p, at each occurrence, are each independently 1, 2, 3, or 4; and

q is 0, 1, 2, 3, or 4;

wherein heteroaryl at each occurrence is independently monocyclic heteroaryl or bicyclic heteroaryl; and

wherein heterocycle at each occurrence is independently monocyclic heterocycle, bicyclic heterocycle, or spirocyclic heterocycle.

2. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, wherein R 2 is —OR 2ac , —SR 2bc , —S(O)R 2bc , —S(O) 2 R 2bc , —C(O)R 2cc , —C(O)OR 2cc , —C(O)N(R 2d )(R 2e ), N(R 2d )(R 2e ), —C(R 2d )═NOR 2dc , G 2a , —(CR 2a R 2b ) p -G 2a , —(CR 2a R 2b ) p —OR 2ac , —(CR 2a R 2b ) p —C(O)OR 2cc , —(CR 2a R 2b ) p —C(O)N(R 2d )(R 2e ), or —(CR 2a R 2b ) p —N(R 2d )(R 2e ).

3. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, wherein

R 2 is —S(O) 2 R 2bc .

4. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, wherein

R 2 is G 2a or —(CR 2a R 2b ) p -G 2a .

5. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, wherein

G 1a is aryl, cycloalkyl, cycloalkenyl, or heterocycle, each of which is optionally substituted as set forth in claim 1 .

6. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, wherein

G 1a is aryl or cycloalkyl, each of which is optionally substituted as set forth in claim 1 .

7. The compound according to claim 1 or a pharmaceutically acceptable salt, solvate, or salt of a solvate thereof, wherein

G 1a is optionally substituted aryl.

8. The compound according to claim 6 or a pharmaceutically acceptable salt thereof, wherein R 2 is —OR 2ac , —SR 2bc , —S(O)R 2bc , —S(O) 2 R 2bc , —C(O)R 2cc , —C(O)OR 2cc , —C(O)N(R 2d )(R 2e ), N(R 2d )(R 2e ), —C(R 2d )═NOR 2dc , G 2a , —(CR 2a R 2b ) p -G 2a ,—(CR 2a R 2b ) p —OR 2ac , —(CR 2a R 2b ) p —C(O)OR 2cc , —(CR 2a R 2b ) p —C(O)N(R 2d )(R 2e ), or —(CR 2a R 2b ) p —N(R 2d )(R 2e ).

9. The compound according to claim 6 or a pharmaceutically acceptable salt thereof, wherein R 2 is —SR 2bc , —S(O)R 2bc , or S(O) 2 R 2bc .

10. The compound according to claim 6 or a pharmaceutically acceptable salt thereof, wherein R 2 is —S(O) 2 R 2bc .

11. The compound according to claim 10 or a pharmaceutically acceptable salt thereof, wherein G 1a is optionally substituted phenyl or optionally substituted naphthyl.

12. The compound according to claim 6 or a pharmaceutically acceptable salt thereof, wherein R 2 is G 2a or —(CR 2a R 2b ) p -G 2a .

13. The compound according to claim 6 or a pharmaceutically acceptable salt thereof, wherein R 2 is G 2a .

14. The compound according to claim 6 or a pharmaceutically acceptable salt thereof, wherein R 2 is G 2a and G 2a is optionally substituted heterocycle.

15. The compound according to claim 14 or a pharmaceutically acceptable salt thereof, wherein G 1a is optionally substituted phenyl or optionally substituted naphthyl.

16. The compound according to claim 6 or a pharmaceutically acceptable salt thereof, wherein R 2 is G 2a and G 2a is optionally substituted heteroaryl.

17. The compound according to claim 16 or a pharmaceutically acceptable salt thereof, wherein G 1a is optionally substituted phenyl or optionally substituted naphthyl.

18. The compound according to claim 6 or a pharmaceutically acceptable salt thereof, wherein R 2 is —C(O)R 2cc or —(CR 2a R 2b ) p —C(O)R 2cc .

19. The compound according to claim 6 or a pharmaceutically acceptable salt thereof, wherein R 2 is N(R 2d )(R 2e ) or —(CR 2a R 2b ) p —N(R 2d )(R 2e ).

20. The compound of formula (I) according to claim 1 or a pharmaceutically acceptable salt thereof, wherein the compound is selected from the group consisting of

2-(3,5-difluorophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(6-chloropyridin-3-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[4-(6-chloropyridin-3-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(3,6-dihydro-2H-pyran-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(3,5-difluorophenyl)-N-[4-(3,6-dihydro-2H-pyran-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[1-oxo-4-(pyridin-3-yl)phthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[1-oxo-4-(pyridin-3-yl)phthalazin-2(1H)-yl]acetamide;

2-(3,5-difluorophenyl)-N-[1-oxo-4-(thiophen-2-yl)phthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[1-oxo-4-(thiophen-2-yl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[1-oxo-4-(thiophen-2-yl)phthalazin-2(1H)-yl]acetamide;

2-[(1S,2S,4S)-bicyclo[2.2.1]hept-5-en-2-yl]-N-[1-oxo-4-(thiophen-2-yl)phthalazin-2(1H)-yl]acetamide;

2-(3,5-difluorophenyl)-N-[4-(3-methylthiophen-2-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[4-(3-methylthiophen-2-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(3-methylthiophen-2-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-[(1S,2S,4S)-bicyclo[2.2.1]hept-5-en-2-yl]-N-[4-(3-methylthiophen-2-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(3,5-difluorophenyl)-N-[1-oxo-4-(pyridin-2-yl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[1-oxo-4-(pyridin-2-yl)phthalazin-2(1H)-yl]acetamide;

2-(3,5-difluorophenyl)-N-[1-oxo-4-(pyrrolidin-1-yl)phthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[1-oxo-4-(pyrrolidin-1-yl)phthalazin-2(1H)-yl]acetamide;

2-(3,5-difluorophenyl)-N-[1-oxo-4-(piperidin-1-yl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[1-oxo-4-(pyrrolidin-1-yl)phthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[1-oxo-4-(piperidin-1-yl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[1-oxo-4-(piperidin-1-yl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(6-methoxypyridin-3-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

N-[4-(6-chloropyridin-3-yl)-1-oxophthalazin-2(1H)-yl]-3-methyl-3-phenylbutanamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[1-oxo-4-(tetrahydro-2H-pyran-4-yl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(2-chloropyridin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{4-[(6-chloropyridin-3-yl)methyl]-1-oxophthalazin-2(1H)-yl}acetamide;

N-{4-[(6-chloropyridin-3-yl)methyl]-1-oxophthalazin-2(1H)-yl}-2-(3,5-difluorophenyl)acetamide;

2-(4-chlorophenyl)-N-{4-[(6-chloropyridin-3-yl)methyl]-1-oxophthalazin-2(1H)-yl}acetamide;

3-methyl-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-3-phenylbutanamide;

(±)-N-[4-(benzylamino)-1-oxophthalazin-2(1H)-yl]-2-[(exo)-bicyclo[2.2.1]hept-2-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{4-[(3-chlorophenyl)amino]-1-oxophthalazin-2(1H)-yl}acetamide;

N-{4-[benzyl(methyl)amino]-1-oxophthalazin-2(1H)-yl}-2-(4-chlorophenyl)acetamide;

(±)-N-{4-[benzyl(methyl)amino]-1-oxophthalazin-2(1H)-yl}-2-[(exo)-bicyclo[2.2.1]hept-2-yl]acetamide;

2-(3,5-difluorophenyl)-N-(1-oxo-4-phenoxyphthalazin-2(1H)-yl)acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-(1-oxo-4-phenoxyphthalazin-2(1H)-yl)acetamide;

(±)-N-(4-benzoyl-1-oxophthalazin-2(1H)-yl)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]acetamide;

tert-butyl [(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

N-[4-(aminomethyl)-1-oxophthalazin-2(1H)-yl]-2-(4-chlorophenyl)acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{1-oxo-4-[6-(trifluoromethyl)pyridin-3-yl]phthalazin-2(1H)-yl}acetamide;

(±)-tert-butyl [(3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(2-cyanopyridin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(2-hydroxypyridin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{4-[6-(dimethylamino)pyridin-3-yl]-1-oxophthalazin-2(1H)-yl}acetamide;

N-[4-(2-chloropyridin-4-yl)-1-oxophthalazin-2(1H)-yl]-3-methyl-3-phenylbutanamide;

2-(4-chlorophenyl)-N-[4-(2-chloropyridin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(2-methylpyridin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-ethyl 3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-4-oxo-3,4-dihydrophthalazine-1-carboxylate;

N-{4-[benzyl(methyl)amino]-1-oxophthalazin-2(1H)-yl}-3-methyl-3-phenylbutanamide;

N-{4-[benzyl(methyl)amino]-1-oxophthalazin-2(1H)-yl}-2-(3,5-difluorophenyl)acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(6-fluoropyridin-3-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-4-oxo-3,4-dihydrophthalazine-1-carboxylic acid;

(±)-3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-N,N-dimethyl-4-oxo-3,4-dihydrophthalazine-1-carboxamide;

2-(3,5-difluorophenyl)-N-[1-oxo-4-(phenylsulfanyl)phthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[1-oxo-4-(phenylsulfanyl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[1-oxo-4-(phenylsulfanyl)phthalazin-2(1H)-yl]acetamide;

2-(3,5-difluorophenyl)-N-[4-(2,6-dimethylmorpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

N-[4-(2,6-dimethylmorpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-3-methyl-3-phenylbutanamide;

2-(4-chlorophenyl)-N-[4-(2,6-dimethylmorpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

ethyl 3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazine-1-carboxylate;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(2,6-dimethylmorpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazine-1-carboxylic acid;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(tetrahydrofuran-3-yl)acetamide;

N-[4-(2-chloropyridin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(tetrahydrofuran-3-yl)acetamide;

2-(3,5-difluorophenyl)-N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]acetamide;

N-[4-(2-chloropyridin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(1-hydroxycyclohexyl)acetamide;

(±)-4-(3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)pyridine-2-carboxamide;

N-[4-(2-chloropyridin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(tetrahydrofuran-2-yl)acetamide;

(±)-methyl 4-(3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)pyridine-2-carboxylate;

(±)-4-(3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)pyridine-2-carboxylic acid;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{1-oxo-4-[2-(trifluoromethyl)pyridin-4-yl]phthalazin-2(1H)-yl}acetamide;

2-(4-chlorophenyl)-N-{1-oxo-4-[2-(trifluoromethyl)pyridin-4-yl]phthalazin-2(1H)-yl}acetamide;

2-(4-chlorophenyl)-N-[4-({[(4-methylphenyl)sulfonyl]amino}methyl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[1-oxo-4-({[(trifluoromethyl)sulfonyl]amino}methyl)phthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[4-{[(methylsulfonyl)amino]methyl}-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-{4-[cis-2,6-dimethylmorpholin-4-yl]-1-oxophthalazin-2(1H)-yl}acetamide;

2-(4-chlorophenyl)-N-[1-oxo-4-(phenylsulfinyl)phthalazin-2(1H)-yl]acetamide;

2-(3,5-difluorophenyl)-N-[1-oxo-4-(phenylsulfinyl)phthalazin-2(1H)-yl]acetamide;

N-[4-{[(tert-butylcarbamoyl)amino]methyl}-1-oxophthalazin-2(1H)-yl]-2-(4-chlorophenyl)acetamide;

ethyl [(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

2-(4-chlorophenyl)-N-[1-oxo-4-{[(phenylacetyl)amino]methyl}phthalazin-2(1H)-yl]acetamide;

N-[(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]-2,2-dimethylpropanamide;

2-(3,5-difluorophenyl)-N-{4-[(cis)-2,6-dimethylmorpholin-4-yl]-1-oxophthalazin-2(1H)-yl}acetamide;

N-{4-[(cis)-2,6-dimethylmorpholin-4-yl]-1-oxophthalazin-2(1H)-yl}-3-methyl-3-phenylbutanamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{4-[(cis)-2,6-dimethylmorpholin-4-yl]-1-oxophthalazin-2(1H)-yl}acetamide;

2-(4-chlorophenyl)-N-[1-oxo-4-(thiomorpholin-4-yl)phthalazin-2(1H)-yl]acetamide;

2-(3,5-difluorophenyl)-N-[1-oxo-4-(thiomorpholin-4-yl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[1-oxo-4-(thiomorpholin-4-yl)phthalazin-2(1H)-yl]acetamide;

(±)-tert-butyl 3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-4-oxo-3,4-dihydrophthalazine-1-carboxylate;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(morpholin-4-ylcarbonyl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-benzyl [(3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-4-oxo-3,4-dihydrophthalazin -1-yl)methyl]carbamate;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[1-oxo-4-(pyridin-4-ylmethyl)phthalazin-2(1H)-yl]acetamide;

(±)-tert-butyl 4-[(3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)carbonyl]piperazine-1-carboxylate;

(±)-3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-N-tert-butyl-4-oxo-3,4-dihydrophthalazine-1-carboxamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{4-[(1-oxidopyridin-4-yl)methyl]-1-oxophthalazin-2(1H)-yl}acetamide;

N-[4-(4-benzylpiperazin-1-yl)-1-oxophthalazin-2(1H)-yl]-2-(4-chlorophenyl)acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{4-[hydroxy(phenyl)methyl]-1-oxophthalazin-2(1H)-yl}acetamide;

tert-butyl {4-[(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)sulfanyl]phenyl}carbamate;

N-{4-[(6-chloro-1-oxidopyridin-3-yl)methyl]-1-oxophthalazin-2(1H)-yl}-2-(4-chlorophenyl)acetamide;

N-{4-[(4-aminophenyl)sulfanyl]-1-oxophthalazin-2(1H)-yl}-2-(4-chlorophenyl)acetamide;

tert-butyl {4-[(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)sulfonyl]phenyl}carbamate;

2-(4-chlorophenyl)-N-[4-(4-methylpiperazin-1-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

(±)-3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-N-(4-chlorophenyl)-4-oxo-3,4-dihydrophthalazine-1-carboxamide;

ethyl 2-(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)propanoate;

2-(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)propanoic acid;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-phenylacetamide;

N-tert-butyl-2-(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)propanamide;

2-(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)-N-(2,2-dimethylpropyl)propanamide;

(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)acetic acid;

N-{4-[(4-aminophenyl)sulfonyl]-1-oxophthalazin-2(1H)-yl}-2-(4-chlorophenyl)acetamide;

ethyl (3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)acetate;

ethyl {[(4-chlorophenyl)acetyl]amino}(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)acetate;

tert-butyl {[4-oxo-3-({[4-(trifluoromethyl)phenyl]acetyl}amino)-3,4-dihydrophthalazin-1-yl]methyl}carbamate;

tert-butyl {[3-({[(1S,2S,5S)-6,6-dimethylbicyclo[3.1.1]hept-2-yl]acetyl}amino)-4-oxo-3,4-dihydrophthalazin-1-yl]methyl}carbamate;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{4-[(Z)-(hydroxyimino)(phenyl)methyl]-1-oxophthalazin-2(1H)-yl}acetamide;

2-(4-chlorophenyl)-N-[4-(2-hydroxyethyl)-1-oxophthalazin-2(1H)-yl]acetamide;

N-{4-[2-(tert-butylamino)-2-oxoethyl]-1-oxophthalazin-2(1H)-yl}-2-(4-chlorophenyl)acetamide;

2-(4-chlorophenyl)-N-[4-{2-[(2,2-dimethylpropyl)amino]-2-oxoethyl}-1-oxophthalazin-2(1H)-yl]acetamide;

tert-butyl [(3-{[(4,4-difluorocyclohexyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

tert-butyl [(3-{[(4-fluorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

tert-butyl ({3-[(cyclohexylacetyl)amino]-4-oxo-3,4-dihydrophthalazin-1-yl}methyl)carbamate;

2-(4-chlorophenyl)-N-(1-oxo-4-phenoxyphthalazin-2(1H)-yl)acetamide;

cyclohexyl [(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

2,2,2-trifluoroethyl [(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

2-[4-(methylsulfonyl)phenyl]-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(3-phenoxyphenyl)acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-[4-(trifluoromethoxy)phenyl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(1,2-benzoxazol-3-yl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-cyclopentyl-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-cyclohexyl-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(2-methylphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(3-methylphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-methylphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(2-nitrophenyl)acetamide;

2-(3-hydroxyphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-hydroxyphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(2-methoxyphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(3-methoxyphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-methoxyphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(2-fluorophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(3-fluorophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-fluorophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(2-chlorophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(3-chlorophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(2-bromophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(3-bromophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-bromophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(3-nitrophenyl)acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(4-nitrophenyl)acetamide;

2-(biphenyl-4-yl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-[4-(dimethylamino)phenyl]-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-[3-(trifluoromethyl)phenyl]acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-[4-(trifluoromethyl)phenyl]acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-[3-(trifluoromethoxy)phenyl]acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(4-phenoxyphenyl)acetamide;

2-[4-(benzyloxy)phenyl]-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(naphthalen-1-yl)acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(naphthalen-2-yl)acetamide;

2-(2,5-dimethylphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]-2-(2,4,6-trimethylphenyl)acetamide;

2-(2,3-dimethoxyphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(2,4-dimethoxyphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(2,5-dimethoxyphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(3,4-dimethoxyphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(3,5-dimethoxyphenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(1,3-benzodioxol-5-yl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(2,3-difluorophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(2,5-difluorophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(3,4-dichlorophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(2,6-dichlorophenyl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

tert-butyl [(3-{[(exo)-bicyclo[2.2.1]hept-2-ylacetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)(phenyl)methyl]carbamate;

(1R,2S,5R)-5-methyl-2-(propan-2-yl)cyclohexyl [(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

2-[4-(methylsulfonyl)phenyl]-N-[1-oxo-4-(phenylsulfanyl)phthalazin-2(1H)-yl]acetamide;

2-methylbutan-2-yl [(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

methyl [(2S)-1-{[(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]amino}-3-methyl-1-oxobutan-2-yl]carbamate;

2,2-dimethylpropyl [(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

2-methylpropyl [(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

(1S,2R,5S)-5-methyl-2-(propan-2-yl)cyclohexyl [(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

cyclopentyl [(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

benzyl [(3-{[(4-chlorophenyl)acetyl]amino}-4-oxo-3,4-dihydrophthalazin-1-yl)methyl]carbamate;

2-[4-(methylsulfonyl)phenyl]-N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(1,1-dioxidothiomorpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[1-oxo-4-(pyridin-4-ylsulfanyl)phthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-{4-[(4-methylphenyl)sulfonyl]-1-oxophthalazin-2(1H)-yl}acetamide;

2-(4-fluorophenyl)-N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]acetamide;

3-methyl-N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]-3-phenylbutanamide;

N-{4-[(4-bromophenyl)sulfanyl]-1-oxophthalazin-2(1H)-yl}-2-(4-chlorophenyl)acetamide;

2-(4-chlorophenyl)-N-{4-[(1-oxidopyridin-4-yl)sulfonyl]-1-oxophthalazin-2(1H)-yl}acetamide;

N-{4-[(4-bromophenyl)sulfanyl]-1-oxophthalazin-2(1H)-yl}-2-(3,5-difluorophenyl)acetamide;

N-[4-(tert-butylsulfanyl)-1-oxophthalazin-2(1H)-yl]-2-(4-chlorophenyl)acetamide;

N-{4-[(4-bromophenyl)sulfonyl]-1-oxophthalazin-2(1H)-yl}-2-(4-chlorophenyl)acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{4-[(4-bromophenyl)sulfanyl]-1-oxophthalazin-2(1H)-yl}acetamide;

N-[4-(tert-butylsulfonyl)-1-oxophthalazin-2(1H)-yl]-2-(4-chlorophenyl)acetamide;

N-{4-[(4-bromophenyl)sulfonyl]-1-oxophthalazin-2(1H)-yl}-2-(3,5-difluorophenyl)acetamide;

2-(4-chlorophenyl)-N-[1-oxo-4-(pyridin-4-ylsulfonyl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{4-[(4-bromophenyl)sulfonyl]-1-oxophthalazin-2(1H)-yl}acetamide;

2-(3-methoxyphenyl)-N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]acetamide;

2-(4-bromophenyl)-N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]acetamide;

2-(3-methylphenyl)-N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]acetamide;

N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]-2-[3-(trifluoromethyl)phenyl]acetamide;

2-(3-chlorophenyl)-N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]acetamide;

2-(hexahydro-2,5-methanopentalen-3a(1H)-yl)-N-[4-(morpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(hexahydro-2,5-methanopentalen-3a(1H)-yl)-N-{1-oxo-4-[6-(trifluoromethyl)pyridin-3-yl]phthalazin-2(1H)-yl}acetamide;

N-[4-(benzylsulfanyl)-1-oxophthalazin-2(1H)-yl]-2-(3,5-difluorophenyl)acetamide;

N-[4-(benzylsulfanyl)-1-oxophthalazin-2(1H)-yl]-2-(4-chlorophenyl)acetamide;

(±)-N-[4-(benzylsulfanyl)-1-oxophthalazin-2(1H)-yl]-2-[(exo)-bicyclo[2.2.1]hept-2-yl]acetamide;

N-[4-(benzylsulfonyl)-1-oxophthalazin-2(1H)-yl]-2-(3,5-difluorophenyl)acetamide;

N-[4-(benzylsulfonyl)-1-oxophthalazin-2(1H)-yl]-2-(4-chlorophenyl)acetamide;

(±)-N-[4-(benzylsulfonyl)-1-oxophthalazin-2(1H)-yl]-2-[(exo)-bicyclo[2.2.1]hept-2-yl]acetamide;

2-(hexahydro-2,5-methanopentalen-3a(1H)-yl)-N-[1-oxo-4-(phenylsulfonyl)phthalazin-2(1H)-yl]acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-{4-[(4-cyanophenyl)sulfonyl]-1-oxophthalazin-2(1H)-yl}acetamide;

(±)-2-[(exo)-bicyclo[2.2.1]hept-2-yl]-N-[4-(2-ethylmorpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-[4-(2-ethylmorpholin-4-yl)-1-oxophthalazin-2(1H)-yl]acetamide;

2-(4-chlorophenyl)-N-{4-[(4-cyanophenyl)sulfonyl]-1-oxophthalazin-2(1H)-yl}acetamide;

N-{4-[(4-cyanophenyl)sulfonyl]-1-oxophthalazin-2(1H)-yl}-2-(3,5-difluorophenyl)acetamide;

N-{4-[(4-cyanophenyl)sulfonyl]-1-oxophthalazin-2(1H)-yl}-2-(4-fluorophenyl)acetamide; and

N-{4-[(4-cyanophenyl)sulfonyl]-1-oxophthalazin-2(1H)-yl}-3-methyl-3-phenylbutanamide.

21. A pharmaceutical composition comprising a therapeutically effective amount of a compound of formula (I) according to claim 1 or a pharmaceutically acceptable salt thereof, in combination with a pharmaceutically acceptable carrier.

22. A method for treating pain in a subject in need of such treatment comprising administering to the subject a therapeutically effective amount of a compound of formula (I) according to claim 1 , or a pharmaceutically acceptable salt thereof, alone or in combination with a pharmaceutically acceptable carrier.