6,7,8,9-tetrahydro-5H-pyrido[2,3-d]azepine dopamine D3 ligands

A compound of Formula I

• wherein
• R1 is selected from the group consisting of hydrogen, C1-C6alkyl, C3-C7cycloalkyl and C3-C7cycloalkylC1-C3alkyl;
• wherein the C1-C6alkyl, C3-C7cycloalkyl and C3-C7cycloalkylC1-C3alkyl are each optionally substituted with one to three independently selected halo, hydroxy or C1-C3alkoxy;
• R2 is independently selected at each occurrence from the group consisting of halo, hydroxy and C1-C3alkyl;
• a is 0, 1, 2, 3 or 4;
• R3 is selected from the group consisting of hydrogen, hydroxy, C1-C6alkyl and C1-C6alkoxy, wherein the C1-C6alkyl and C1-C6alkoxy are each optionally substituted with 1 to 3 fluoro;
• R4 is hydrogen or C1-C6alkyl optionally substituted with one to three substituents independently selected from the group consisting of fluoro, C1-C3alkoxy and hydroxy;
• A is selected from the group consisting of C6-C10aryl and 5- to 10-membered heteroaryl;
• wherein the C6-C10aryl and 5- to 10-membered heteroaryl are optionally substituted with 1 to 3 R6;
• R5 is selected from the group consisting of halo, C1-C6alkyl, C1-C6alkoxy, C1-C6alkoxyC1-C6alkyl, C3-C7cycloalkyl, C3-C7cycloalkylC1-C6alkyl, C3-C7cycloalkoxy, phenoxy, 4- to 10-membered heterocycloalkyl and 4- to 10-membered heterocycloalkoxy;
• wherein the C1-C6alkyl, C1-C6alkoxy and C1-C6alkoxyC1-C6alkyl are optionally substituted with one to four independently selected halo or hydroxy;
• and wherein the C3-C7cycloalkyl, C3-C7cycloalkylC1-C6alkyl, C3-C7cycloalkoxy, phenoxy, 4- to 10-membered heterocycloalkyl and 4- to 10-membered heterocycloalkoxy are optionally substituted with one to four R7;
• or R4 and R5 taken together are a C1-C3alkylene;
• R6 is selected from the group consisting of halo, cyano, C1-C6alkyl optionally substituted with one to three fluoro, C1-C6alkoxy optionally substituted with one to three fluoro, and C1-C6alkoxyC1-C6alkyl;
• or R4 and R6 taken together are a C1-C3alkylene;
• or R5 and R6 when attached to adjacent carbons and taken together with the adjacent carbons to which they are attached form a fused 5- to 7-membered cycloalkyl ring or a 5- to 7-membered heterocycloalkyl ring, each of which is optionally substituted with one to four R8;
• R7 at each occurrence is independently selected from the group consisting of halo, hydroxy, C1-C3alkyl optionally substituted with one to three fluoro or C1-C3alkoxy, and C1-C3alkoxy optionally substituted with one to three fluoro;
• and
• R8 at each occurrence is independently selected from halo, hydroxy, C1-C3alkyl optionally substituted with one to three fluoro, and C1-C3alkoxy optionally substituted with one to three fluoro;
• or a pharmaceutically acceptable salt thereof.