Heterocyclic compounds as ERK inhibitors

1. A compound of Formula I

or a pharmaceutically acceptable salt thereof, wherein:

R is selected from the group consisting of: H, alkyl and hydroxylalkyl;

R 1 is selected from the group consisting of heterocyclyl, heterocycloalkenyl, aryl and heteroaryl, wherein when said heterocyclyl, heterocycloalkenyl, aryl or heteroaryl has two substituents on adjacent ring atoms, said substituents together with the ring atoms to which they are attached, optionally form a five- or six-membered heterocyclyl, aryl or heteroaryl;

R 2 is H or alkyl;

R 3′ is selected from the group consisting of:

each R 3 independently is selected from the group consisting of —C(═O)—O-alkyl, halo, haloalkyl, —OSi(alkyl) 3 , —C(═O)—OH, —C(O)NR B R C —C(O)NH-alkyl-NR D R E , —C(O)NH-alkyl-O-alkyl-aryl, —C(O)R F , —C(O)NH—NHR G , —C(O)NH—Oalkyl, —C(O)NH—O-alkyl-cycloalkyl, alkyl, hydroxyl, alkoxy, alkenyl, cycloalkyl, cycloalkenyl, alkynyl, heterocyclyl, heterocyclenyl, aryl, and heteroaryl; or wherein two R 3 groups together with the carbon atom to which both R 3 groups are attached form —C(═O)—;

R B and R C are each independently selected from the group consisting of: H, alkyl, cycloalkyl, cycloalkylalkyl-, heteroaryl, aryl, heterocycloalkyl, benzyl, and alkoxy, wherein said alkyl, cycloalkyl, cycloalkylalkyl-, heteroaryl, aryl, heterocycloalkyl, benzyl, and alkoxy groups are optionally substituted with 1 to 3 substitutents independently selected from the group consisting of: —OH, alkyl, alkoxy, hydroxyalkyl-, halo, and —C(O)Oalkyl;

R D and R E are each independently selected from the group consisting of: H, alkyl, and —C(O)Oalkyl;

R F is a heterocycloalkyl optionally substituted with 1-3 substitutents independently selected from the group consisting of: —OH, halo, —C(O)Oalkyl, —C(O)NH-alkyl, —C(O)alkyl, alkyl, —C(O)Ocycloalkyl, —O—Si(alkyl) 2 (wherein each alkyl is independently selected), and —C(O)Oheterocycloalkyl;

R G is selected from the group consisting of: H, alkyl, and —C(═S)—NH-alkyl;

each m independently is 0, 1, 2 or 3;

n independently is 1;

Each R 4 is independently selected from the group consisting of: H, alkyl, cycloalkyl, aryl, heteroaryl, —SO 2 -aryl, —C(O)—O-alkyl, —C(O)—O-alkylaryl, and —(CR 5 R 6 ) p R 7 , wherein p is 1 or 2; wherein when said R 4 cycloalkyl has two substituents on adjacent carbon atoms, said substituents together with the carbon atoms to which they are attached, optionally form a five- or six-membered ring selected from the group consisting of heterocyclyl, aryl and heteroaryl;

R 4′ is selected from the group consisting of H and alkyl;

R a is alkyl;

R 5 and R 6 independently are selected from the group consisting of H, D, halo, —OH, —C(O)NR H R 2 , —C(O)—O-alkyl, and alkyl; or wherein one —CR 5 R 6 — is —C(═O)—;

R H is selected from the group consisting of H and alkyl; and

R 7 is selected from the group consisting of H, —O-alkyl-aryl, aryl and heteroaryl, wherein when said aryl or heteroaryl has two substituents on adjacent carbon atoms, said substituents together with the carbon atoms to which they are attached, optionally form a five- or six-membered ring selected from the group consisting of cycloalkylheterocyclyl, aryl or heteroaryl.

2. The compound of claim 1 , wherein R is H.

3. The compound of claim 1 , wherein R 1 is selected from the group consisting of:

(a) heteroaryl, wherein said heteroaryl optionally with said five- or six-membered heterocyclyl, aryl or heteroaryl is selected from the group consisting of imidazo[1,2-a]pyridinyl, pyridyl, pyrazolyl, [1,2,4]triazolo[1,5-a]pyridinyl, and [1,2,4]triazolo[4,3-]pyridinyl, each of which is independently unsubstituted or substituted with at least one substituent independently selected from the group consisting of alkyl, cycloalkyl, haloalkyl, alkoxy and halo;

(b) aryl, wherein when said aryl has two substituents on adjacent carbon atoms, said substituents together with the carbon atoms to which they are attached, optionally form a five- or six-membered ring selected from the group consisting of heterocyclyl, aryl and heteroaryl; wherein said aryl optionally with said five- or six-membered heterocyclyl, aryl and heteroaryl is independently unsubstituted or substituted with at least one substitutent selected from the group consisting of alkyl, alkoxy, hydroxy, —NH—C(═O)-alkyl, —S(═O) 2 —N(alkyl) 2 , —C(═O)-alkyl, cyano, —S(═O) 2 -alkyl, —NH 2 , and —OC(═O)alkyl,

(c) aryl, optionally with said five- or six-membered heterocyclyl, aryl and heteroaryl selected from the group consisting of phenyl, benzo[c][1,2,5]thiadiazolyl, benzo[c][1,2,5]oxadiazolyl, 2H-indazolyl, benzotetrahydrofuranyl, benzothiophenyl, benzopyrrolyl, benzopyrazolyl, benzothiazolyl, benzofuranyl, and benzoxazolyl, each of which independently is unsubstituted or substituted with at least one substitutent selected from the group consisting of alkyl, alkoxy, hydroxy, —NH—C(═O)-alkyl, —S(═O) 2 —N(alkyl) 2 , —C(═O)-alkyl, cyano, —S(═O) 2 -alkyl, —NH 2 , and —OC(═O)alkyl; and

(d) heterocyclyl, wherein said heterocyclyl optionally with said five- or six-membered heterocyclyl, aryl and heteroaryl is selected from the group consisting of:

wherein the second structure is unsubstituted or substituted with a cycloalkyl group.

4. The compound of claim 1 wherein R 1 is selected from the group consisting of: phenyl, pyridyl, methylpyridyl, methylindazolyl, methylbenzothiazolyl, pyridazinyl, dihydropyran, dioxidodihydrothiopyran, dioxidotetrahydrothiopyran, imidazolyl, teterahydropyran, benzofuranyl, indazolyl, pyridazinyl, indazolyl, imidazopyridly, benzooxazolyl, benzothiadiazolyl, benzooxadiazolyl, benzothiazolyl, pyridine-one, triazolopyridinyl, dihydrobenzoimidazolyl, benzohydrofuranyl; and wherein said R 1 is optionally substituted with 1 or more substitutents independently selected from the group consisting of: ═O, —OH, alkyl, cycloalkyl, haloalkyl, alkoxy, halo, —NH—C(═O)-alkyl, —S(═O) 2 —N(alkyl) 2 , —C(═O)-alkyl, cyano, —S(═O) 2 -alkyl, —NH 2 , and —OC(═O)alkyl.

5. The compound of claim 1 , wherein said R 2 is alkyl, which is unsubstituted or substituted with at least one aryl.

6. The compound of claim 1 , wherein R 3′ is

wherein n is 1.

7. The compound of claim 6 , wherein:

(a) n is 1; or

(b) n is 1 and m is 0, 1 or 2; or

(c) n is 1, m is 1 or 2, and R 3 is selected from the group consisting of halo, haloalkyl, —OSi(alkyl) 3 , hydroxyl, alkyl, cycloalkyl, alkoxy, aryl, —C(═O)OH, —C(═O)—O-alkyl, —C(═O)N(alkyl) 3 , —C(═O)NH-alkyl; or wherein two R 3 groups together with the carbon atom to which both R 3 groups are attached form —C(═O)—.

8. The compound of claim 1 wherein:

(1) R 3 is selected from the group consisting of

(a) —C(O)NR B R C , wherein R B and R C are each independently selected from the group consisting of (1) H, (2) C 1 -C 6 alkyl, (3) C 3 -C 6 cycloalkyl, (4) C 3 -C 6 cycloalkyl-C 1 -C 6 alkyl-, (5) 5-6 membered heteroaryl comprising 1 to 3 heteroatoms selected from the group consisting of N, O, and S, (6) C 6 -C 10 aryl, (7) benzyl, (8) C 1 -C 2 alkoxy; wherein each of said R B and R C is optionally substituted with 1 to 3 substitutents independently selected from the group consisting of: —OH, C 1 -C 4 alkyl, —C 1 -C 4 alkoxy, -hydroxy(C 1 -C 3 )alkyl-, halo, —C(O)OC 1 -C 4 alkyl, and the optional substitution of R B is independent of the optional substitution of R C ;

(b) —C(O)NH-alkyl-NR D R E , and R D and R E are independently selected from the group consisting of: H, C 1 -C 4 alkyl and —C(O)OC 1 -C 4 alkyl;

(c) —C(O)—NH—C 1 -C 2 alkyl-O—C 1 -C 2 alkyl-phenyl,

(d) —C(O)R F wherein R F is selected from the group consisting of pyrrolidinyl, piperidinyl, piperazinyl, azetidinyl, morpholinyl, and isoxazolidinyl, and said R F group is optionally substituted with 1-3 substituents independently selected from the group consisting of: —OH, halo, —C(O)OC 1 -C 4 alkyl, —C(O)NH—C 1 -C 4 alkyl, —C(O)C 1 -C 4 alkyl, —C(O)OC 3 -C 6 cycloalkyl, —O—Si(C 1 -C 4 alkyl) 2 wherein each alkyl is independently selected, and —C(O)Oheterocycloalkyl wherein said heterocycloalkyl moiety is a 5 to 6 membered ring comprising 1 to 3 heteroatoms selected from the group consisting of O, N and S;

(e) —C(O)—NH—NHR G wherein R G is selected from the group consisting of: H, C 1 -C 4 alkyl, and —C(═S)—NH—C 1 -C 4 alkyl;

(f) —C(O)NH—O—C 1 -C 4 alkyl;

(g) —C(═O)—N(alkyl) 2 , wherein each alkyl group is independently selected;

(h) —C(═O)—NHalkyl;

(i) phenyl;

(j) —C(O)NH—O—C 1 -C 2 alkyl-C 3 -C 5 cycloalkyl;

(2) R 3′ is

(3) m is 1; and

(4) n is 1.

9. The compound of claim 6 wherein R 4 is selected from the group consisting of:

(a) H;

(b) cycloalkyl, wherein when said R 4 cycloalkyl has two substituents on adjacent carbon atoms, said substituents together with the carbon atoms to which they are attached, optionally form a six-membered aryl; and

(c) —(CR 5 R 6 ) 1-2 R 7 , wherein each of R 5 and R 6 independently is H or alkyl, or wherein one —CR 5 R 6 — together is —C(═O)— and R 7 is selected from the group consisting of H, cycloalkyl, heterocyclyl, —O-alkyl-aryl, aryl and heteroaryl, wherein when each of said R 7 cycloalkyl, heterocyclyl, aryl and heteroaryl has two substituents on adjacent carbon atoms, said substituents together with the carbon atoms to which they are attached, optionally form a five- or six-membered cycloalkyl, heterocyclyl, aryl or heteroaryl.

10. The compound of claim 1 wherein R 4 is selected from the group consisting of: phenyl, quinolinyl, —SO 2 -phenyl, —CH 2 -phenyl, di-F-phenyl, F-phenyl, —CH 2 -thienyl, —(CH 2 ) 2 -phenyl, —CH 2 -(D 3 CO—, F-phenyl), —CH(C(O)NH 2 )(F-phenyl), —CH(C(O)NHCH 3 )(F-phenyl), —CH(C(O)NH 2 )(di-F-phenyl), —CH(C(O)NHCH 3 )(di-F-phenyl), —CH(C(O)N(CH 3 ) 2 )(di-F-phenyl), —CH(C(O)N(CH 3 ) 2 )(F-phenyl), and —CH(C(O)OCH 3 )(di-F-phenyl).

11. The compound of claim 1 , wherein R 3′ is selected from the group consisting of:

wherein m is 0, and R 4 is —CR 5 R 6 R 7 ;

wherein m is 0, and R 4 is —CR 5 R 6 R 7 ;

wherein n is 1, m is 0, and R 4 is —CR 5 R 6 R 7 ;

and

wherein R 4′ is H, and R a is alkyl which is unsubstituted or substituted with an aryl substituent.

12. The compound of claim 1 selected from the group consisting of:

or a pharmaceutically acceptable salt, solvate or ester thereof.

13. A pharmaceutical composition comprising at least one compound of claim 1 , or a pharmaceutically acceptable salt, solvate or ester thereof, and a pharmaceutically acceptable carrier.

14. A compound of claim 1 , or a pharmaceutically acceptable salt, thereof, for use in inhibiting ERK.

15. A compound selected from the group consisting of