DNA-PK inhibitors

A compound represented by the following formula:

• or a pharmaceutically acceptable salt thereof, wherein
• Ring A is an aromatic ring system selected from
• Ring B is a ring system selected from
• wherein Ring B is optionally substituted with one or more substituents selected from the group consisting of —F, —OH, and C1-4alkyl optionally substituted with one or more substituents selected from the group consisting of —F, —Cl, —OH, and —OC1-2alkyl;
• Ring C is a C4-6 cycloalkyl, 5-6-membered heteroaryl, or phenyl group, wherein Ring C is optionally further substituted with one or more substituents selected from the group consisting of halogen, C1-2 alkyl, —OH, and —OC1-2alkyl;
• X is —NH—, —O—, —OC1-4 alkyl-, —S—, or —CH2—;
• each of R1 and R2 is, independently, hydrogen, —C(O)NHR4, —C(O)OR4, —NHC(O)R4,
• —NHC(O)OR4, —NHC(O)NHR4, —NHS(O)2R4, —NHR4, —C1-4 alkyl-NHR4, —OR4, or R7 wherein R1 and R2 cannot simultaneously be hydrogen;
• each R3 independently is hydrogen, —C1-4alkyl,
• halogen, —OC1-2alkyl, —C(O)OH, —C(O)OC1-2alkyl, —CN, —C(O)NHC1-2alkyl, —C(O)NH2, C3-4 cycloalkyl, or —NRR′, wherein each of said R3 alkyl and cycloalkyl independently is optionally substituted with one or more substituents selected from the group consisting of —F, —Cl, —OH and —OC1-2alkyl;
• each R4 independently is hydrogen, C1-4alkyl, C2-4alkenyl, C2-4alkynyl, C3-10 cycloalkyl, 6-10 membered aryl, 5-10-membered heteroaryl, or 4-10-membered heterocyclyl, wherein each of said R4 groups is optionally and independently substituted with one or more substituents selected from the group consisting of —Br, —Cl, —F, C1-4alkyl, CN, NO2, C2-4alkenyl, C2-4alkynyl, C3-6cycloalkyl, C0-4 alkyl-C3-5 cycloalkyl, C0-4 alkyl-O—C1-4 alkyl, C0-4 alkyl-O—C0-4 alkyl-C3-5 cycloalkyl, C(O)OC1-4 alkyl, C(O)OC0-4 alkyl-C3-5 cycloalkyl, C0-4 alkyl-C(O)NH2, C(O)NHC1-4 alkyl, C(O)N(C1-4 alkyl)2, C(O)NH(Co1-4 alkyl-C3-5 cycloalkyl), CH2OR5, C0-4 alkyl-C(O)R5, C0-4 alkyl-C(O)N(R5)2, C0-4 alkyl-C(O)OR5, C0-4 alkyl-NHC(O)R5, C0-4 alkyl-N(R5)2, 5-6 membered heterocyclyl, —O(C1-4 alkyl)OR5, —OR5, and oxo, and wherein each of said optional R4 substituents is optionally and independently substituted with one or more substituents selected from the group consisting of —F, —Cl, C1-4alkyl, —OH, —OC1-4alkyl, —SC1-4alkyl, —C(O)C1-4 alkyl, —C(O)OC1-4 alkyl, and —C(O)OC0-4 alkyl-C3-5 cycloalkyl;
• and
• each R5 independently is hydrogen, C1-4alkyl, phenyl, 5-6-membered heteroaryl, or 4-7-membered heterocyclyl, wherein each R5 is optionally and independently substituted with one or more substituents selected from the group consisting of —F, —Cl, C1-2alkyl, —CH2OH,
• —CN, —OH, —OC1-2alkyl, 5-6-membered heteroaryl, and 4-7 membered heterocyclyl, or two R5 groups together with the intervening nitrogen atom optionally form a morpholine ring, azetidine ring, pyrrolidine ring, piperidine ring, or piperazine ring;
• and
• R6 is hydrogen or C1-4alkyl optionally substituted with one or more substituents selected from the group consisting of —F, —Cl, —CH2OH, —CN, —OH, and —OC1-2alkyl;
• R7 is 6-10-membered aryl, 5-10-membered heteroaryl, or 4-7-membered heterocyclyl, each of which is optionally and independently substituted with one or more substituents selected from the group consisting of —F, —Cl,
• C1-2alkyl, —CH2OH, —CN, and —OR;
• and
• each of R and R′ independently is hydrogen or C1-4alkyl, or R and R′ together with the nitrogen atom to which they are attached optionally form a morpholine ring, azetidine ring, pyrrolidine ring, piperidine ring, or piperazine ring.