Heterocyclic and heteroaryl compounds for treating huntington's disease

A compound of Formula (Ip1):

• or a form thereof, wherein:
• Ra is, in each instance, independently selected from hydrogen, cyano, halogen, hydroxy, C1-6alkyl, deutero-C1-4alkyl, halo-C1-6alkyl, C1-6alkoxy, halo-C1-6alkoxy, C1-6alkoxy-C1-6alkyl, amino, C1-6alkyl-amino, (C1-6alkyl)2-amino, amino-C1-6alkyl, and hydroxy-C1-6alkyl;
• Rb is selected from hydrogen and C1-6alkyl;
• R1 is selected from C3-10cycloalkyl and heterocyclyl,
• wherein heterocyclyl is a saturated or partially unsaturated 3-7 membered monocyclic, 6-10 membered bicyclic or 13-16 membered polycyclic ring system having 1, 2, or 3 heteroatom ring members independently selected from N, O, or S, and
• wherein, each instance of C3-10cycloalkyl and heterocyclyl is optionally substituted with one, two or three R3 substituents and optionally, with one additional R4 substituent, or,
• wherein, alternatively, each instance of C3-10cycloalkyl and heterocyclyl is optionally substituted with one, two, three, or four R3 substituents;
• R2 is selected from phenyl, heterocyclyl, and heteroaryl,
• wherein heterocyclyl is a saturated or partially unsaturated 3-7 membered monocyclic, 6-10 membered bicyclic or 13-16 membered polycyclic ring system having 1, 2, or 3 heteroatom ring members independently selected from N, O, or S,
• wherein heteroaryl is a 3-7 membered monocyclic or 6-10 membered bicyclic ring system having 1, 2, 3, or 4 heteroatom ring members independently selected from N, O, or S, and
• R3 is, in each instance, independently selected from cyano, halogen, hydroxy, C1-6alkyl, deutero-C1-4alkyl, halo-C1-6alkyl, C1-6alkoxy, halo-C1-6alkoxy, C1-6alkoxy-C1-6alkyl, amino, C1-6alkyl-amino, (C1-6alkyl)2-amino, amino-C1-6alkyl, and hydroxy-C1-6alkyl;
• R4 is selected from C3-10cycloalkyl, phenyl, heteroaryl, and heterocyclyl,
• wherein heterocyclyl is a saturated or partially unsaturated 3-7 membered monocyclic, 6-10 membered bicyclic or 13-16 membered polycyclic ring system having 1, 2, or 3 heteroatom ring members independently selected from N, O, or S,
• wherein heteroaryl is a 3-7 membered monocyclic or 6-10 membered bicyclic ring system having 1, 2, 3, or 4 heteroatom ring members independently selected from N, O, or S, and
• wherein, each instance of C3-10cycloalkyl, phenyl, heterocyclyl, and heteroaryl is optionally substituted with one, two, or three R7 substituents;
• R5 is, in each instance, independently selected from halogen, hydroxy, cyano, nitro, C1-6alkyl, deutero-C1-4alkyl, halo-C1-6alkyl, C1-6alkoxy, halo-C1-6alkoxy, oxime, amino, C1-6alkyl-amino, (C1-6alkyl)2-amino, and C1-6alkyl-thio;
• R6 is selected from phenyl and heteroaryl,
• wherein heteroaryl is a 3-7 membered monocyclic or 6-10 membered bicyclic ring system having 1, 2, 3, or 4 heteroatom ring members independently selected from N, O, or S, and
• wherein, each instance of phenyl and heteroaryl is optionally substituted with one, two, three or four R8 substituents;
• R7 is, in each instance, independently selected from cyano, halogen, hydroxy, C1-6alkyl, deutero-C1-4alkyl, halo-C1-6alkyl, C1-6alkoxy, halo-C1-6alkoxy, C1-6alkoxy-C1-6alkyl, amino, C1-6alkyl-amino, (C1-6alkyl)2-amino, amino-C1-6alkyl, and C3-10cycloalkyl;
• and
• R8 is, in each instance, independently selected from cyano, halogen, hydroxy, C1-6alkyl, deutero-C1-4alkyl, halo-C1-6alkyl, C1-6alkoxy, halo-C1-6alkoxy, C1-6alkoxy-C1-6alkyl, amino, C1-6alkyl-amino, (C1-6alkyl)2-amino, amino-C1-6alkyl, and C3-10cycloalkyl;
• wherein a form of the compound is selected from the group consisting of salt, hydrate, solvate, racemate, enantiomer, diastereomer, stereoisomer, and tautomer form thereof.