3-alkyl bicyclic [4,5,0] hydroxamic acids as HDAC inhibitors

1. A compound of Formula I:

or a pharmaceutically acceptable salt thereof, wherein:

X 1 is O;

X 2 and X 4 are each CR 1 R 2 ;

X 3 is CR 1′ R 2′ ;

Y 1 and Y 4 are not bonded to —C(O)NHOH and are each CR 1 ;

Y 2 and Y 3 are each CR 1 when not bonded to C(O)NHOH and Y 2 and Y 3 are C when bonded to —C(O)NHOH;

L is selected from a group consisting of a bond, —(CR 1 R 2 ) n —, —C(O)O—, —C(O)NR 3 —, —S(O) 2 —, —S(O) 2 NR 3 —, —S(O)—, and —S(O)NR 3 —, wherein L is bound to the ring nitrogen through the carbonyl or sulfonyl group;

R is independently selected from the group consisting of —H, —C 1 -C 6 alkyl, —C 2 -C 6 alkenyl, —C 4 -C 8 cycloalkenyl, —C 2 -C 6 alkynyl, —C 3 -C 8 cycloalkyl, —C 5 -C 12 spirocyclyl, heterocyclyl, spiroheterocyclyl, aryl, and heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, and O, wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, spirocyclyl, heterocyclyl, spiroheterocyclyl, aryl, or heteroaryl is optionally substituted with one or more substituents selected from the group consisting of —OH, halogen, oxo, —NO 2 , —CN, —R 2 , —OR 3 , —NHR 3 , —NR 3 R 4 , —S(O) 2 NR 3 R 4 , —S(O) 2 R 1 , —C(O)R 1 , —CO 2 R 1 , —NR 3 S(O) 2 R 1 , —S(O)R 1 , —S(O)NR 3 R 4 , —NR 3 S(O)R 1 , heterocyclyl, aryl, and heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, and O;

each R 1 and R 2 are independently, and at each occurrence, selected from the group consisting of —H, —R 3 , —R 4 , —C 1 -C 6 alkyl, —C 2 -C 6 alkenyl, —C 4 -C 8 cycloalkenyl, —C 2 -C 6 alkynyl, —C 3 -C 8 cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, and O, —OH, halogen, —NO 2 , —CN, —NHC 1 -C 6 alkyl, —N(C 1 -C 6 alkyl) 2 , —S(O) 2 N(C 1 -C 6 alkyl) 2 , —N(C 1 -C 6 alkyl)S(O) 2 R 5 , —S(O) 2 (C 1 -C 6 alkyl), —(C 1 -C 6 alkyl)S(O) 2 R 5 , —C(O)C 1 -C 6 alkyl, —CO 2 C 1 -C 6 alkyl, —N(C 1 -C 6 alkyl)S(O) 2 C 1 -C 6 alkyl, and —(CHR 5 ) n —NR 3 R 4 , wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl is optionally substituted with one or more substituents selected from the group consisting of —OH, halogen, —NO 2 , oxo, —CN, —R 5 , —OR 3 , —NHR 3 , —NR 3 R 4 , —S(O) 2 N(R 3 ) 2 [H], —S(O) 2 R 5 , —C(O)R 5 , —CO 2 R 5 , —NR 3 S(O) 2 R 5 , —S(O)R 5 , —S(O)NR 3 R 4 , —NR 3 S(O)R 5 , heterocyclyl, aryl, and heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, and O;

R 1′ and R 2′ combine with the carbon atom to which they are both attached to form a spirocycle, spiroheterocycle, or a spirocycloalkenyl;

R 3 and R 4 are independently, at each occurrence, selected from the group consisting of —H, —C 1 -C 6 alkyl, —C 2 -C 6 alkenyl, —C 4 -C 8 cycloalkenyl, —C 2 -C 6 alkynyl, —C 3 -C 8 cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, and O, —S(O) 2 N(C 1 -C 6 alkyl) 2 , —S(O) 2 (C 1 -C 6 alkyl), —(C 1 -C 6 alkyl)S(O) 2 R 5 , —C(O)C 1 -C 6 alkyl, —CO 2 C 1 -C 6 alkyl, or —(CHR 5 ) n N(C 1 -C 6 alkyl) 2 , wherein each alkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl is optionally substituted with one or more substituents selected from the group consisting of —OH, halogen, —NO 2 , oxo, —CN, —R 5 , —O(C 1 -C 6 alkyl), —NH(C 1 -C 6 alkyl), —N(C 1 -C 6 alkyl) 2 , —S(O) 2 N(C 1 -C 6 alkyl) 2 , —S(O) 2 NH(C 1 -C 6 alkyl), —C(O)C 1 -C 6 alkyl, —CO 2 C 1 -C 6 alkyl, —N(C 1 -C 6 alkyl)S(O) 2 C 1 -C 6 alkyl, —S(O)R 5 , —S(O)N(C 1 -C 6 alkyl) 2 , —N(C 1 -C 6 alkyl)S(O)R 5 , heterocyclyl, aryl, and heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, and O;

or R 3 and R can combine with the nitrogen atom to which they are attached to form a heterocycle, wherein each heterocycle is optionally substituted by —R 1 , —R 2 , —R 4 , —OR 4 , or —NR 4 R 5 ;

R 5 is independently, and at each occurrence, selected from the group consisting of —H, —C 1 -C 6 alkyl, —C 2 -C 6 alkenyl, —C 4 -C 8 cycloalkenyl, —C 2 -C 6 alkynyl, —C 3 -C 8 cycloalkyl, heterocyclyl, aryl, heteroaryl containing 1-5 heteroatoms selected from the group consisting of N, S, P, and O, —OH, halogen, —NO 2 , —CN, —NHC 1 -C 6 alkyl, —N(C 1 -C 6 alkyl) 2 , —S(O) 2 NH(C 1 -C 6 alkyl), —S(O) 2 N(C 1 -C 6 alkyl) 2 , —S(O) 2 C 1 -C 6 alkyl, —C(O)C 1 -C 6 alkyl, —CO 2 C 1 -C 6 alkyl, —N(C 1 -C 6 alkyl)SO 2 C 1 -C 6 alkyl, —S(O)(C 1 -C 6 alkyl), —S(O)N(C 1 -C 6 alkyl) 2 , —N(C 1 -C 6 alkyl)S(O)(C 1 -C 6 alkyl), and —(CH 2 ) n N(C 1 -C 6 alkyl) 2 ; and

n is independently, and at each occurrence, an integer from 0 to 6.

2. The compound of claim 1 , wherein the compound is of the Formula IA:

or a pharmaceutically acceptable salt thereof.

3. The compound of claim 2 , wherein the compound is of Formula IA-1a:

or a pharmaceutically acceptable salt thereof.

4. The compound of claim 2 , wherein the compound is of Formula IA-1d:

or a pharmaceutically acceptable salt thereof.

5. The compound of claim 2 , wherein the compound is of Formula IA-1f:

or a pharmaceutically acceptable salt thereof.

6. The compound of claim 1 , wherein the compound is of the Formula IB

or a pharmaceutically acceptable salt thereof.

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

N-hydroxy-4-methyl-4,5-dihydro-2H-spiro[benzo[f][1,4]oxazepine-3,1′-cyclopropane]-8-carboxamide;

N-hydroxy-4-phenyl-4,5-dihydro-2H-spiro[benzo[f][1,4]oxazepine-3,1′-cyclopropane]-8-carboxamide; and

N-hydroxy-4-(4-methoxybenzyl)-4,5-dihydro-2H-spiro[benzo[f][1,4]oxazepine-3,1′-cyclopropane]-8-carboxamide.

8. The compound of claim 1 , wherein R 1′ and R 2′ combine to form a spirocycle, wherein the carbon atom to which R 1′ and R 2′ are attached is part of a cyclopropyl ring.

9. The compound of claim 8 , wherein L is —C(O)NR 3 —.

10. The compound of claim 9 , wherein R 3 and R combine with the nitrogen atom to which they are attached to form an optionally substituted heterocycle.

11. The compound of claim 8 , wherein L is a bond.

12. The compound of claim 11 , wherein R is —C 1 -C 6 alkyl substituted with an optionally substituted group selected from the group consisting of aryl, heteroaryl, or —C 3 -C 8 cycloalkyl.

13. The compound of claim 8 , wherein L is —(CR 1 R 2 ) n —.

14. The compound of claim 13 , wherein n is 1.

15. The compound of claim 14 , wherein R is optionally substituted aryl.

16. A pharmaceutical composition comprising a compound of claim 1 , and a pharmaceutically acceptable carrier.