Novel ergolines and methods of treating mood disorders

A compound of Formula (I):

• or a pharmaceutically acceptable salt thereof,
• wherein
• R1 is C1-C6 alkyl or 3-7 membered carbocyclyl, wherein R1 is optionally substituted with one or more halogen or C1-C6 alkyl;
• R2 is hydrogen or C1-C6 alkyl, wherein R2 is optionally substituted with one or more halogen or C1-C6 alkyl;
• or
• wherein R1 and R2 can be taken together with the atom on which they are attached to form an optionally substituted 3-7 membered heterocyclyl comprising 1-3 heteroatoms selected from the group consisting of N, O, and S, wherein the heterocyclyl is optionally substituted with one or more fluoro or C1-C6 alkyl;
• R3 is selected from the group consisting of C2-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, —CH2-(cyclopropyl), and 3-7 membered cycloalkyl,
• wherein R3 may be substituted with one or more substituents each independently selected from the group consisting of fluoro, hydroxyl, and —OMe;
• or
• R3 is selected from the group consisting of —(C1-C2 alkyl)-phenyl and —(C1-C2 alkyl)-(6-membered heteroaryl),
• wherein C1-C2 alkyl is optionally substituted with one or more fluoro, hydroxyl, and —OMe, and wherein phenyl and 6-membered heteroaryl are optionally substituted with one or more substituents each independently selected from the group consisting of halogen, hydroxyl, —OC(O)(C1-C8 alkyl), —CN, —NO2, —NH2, —C(O)NH2, C1-C4 alkyl, C3-C5 cycloalkyl, and C1-C4 alkoxy;
• R4 is hydrogen or —C(O)(C1-C8 alkyl);
• R5 is hydrogen or halogen;
• R6 is hydrogen or deuterium;
• wherein when R1 and R2 are both ethyl, and R4 and R5 are both hydrogen, R3 is not unsubstituted linear C2-C6 alkyl, isopropyl, —CH2CH═CH2, —CH2CH2F, or —CH2CH2Ph;
• wherein when R1 and R2 are both ethyl, R4 is —C(O)(C2 alkyl), and R5 is hydrogen, R3 is not unsubstituted ethyl;
• wherein when R1 is ethyl and R2 is H, R3 is not unsubstituted ethyl, unsubstituted n-propyl, or —CH2CH═CH2.