C17, C20, and C21 substituted neuroactive steroids and their methods of use

A compound of Formula (1-A):

• or a pharmaceutically acceptable salt thereof, wherein:
• a) the compound of Formula (1-A) is a compound of Formula (1-A-1)
• wherein each instance of RY4 is independently alkyl, cyano, or halo;
• and e is 0, 1, 2, 3, 4, or 5;
• or
• b) the compound of Formula (1-A) is a compound of Formula (1-A-3)
• wherein RY1 is hydrogen, —CH3, —CH2CH3, —CH(CH3)2, or cycloalkyl;
• RY2 is alkyl, cycloalkyl, heterocycyl, aryl, or heteroaryl;
• and b is 0, 1, 2, or 3;
• or
• c) the compound of Formula (1-A) is a compound of Formula (1-A-5)
• wherein each occurrence of RY3 is aryl or heteroaryl;
• two RY3 groups are joined together to form a 6-10 membered ring;
• c is 0, 1, 2, or 3;
• and d is 0, 1, 2, or 3,
• and wherein
• R3 is —CH3, —CF3, —CH2OCH3, —CH2OCH2CH3;
• each of RX and RY is independently hydrogen, aryl, or alkyl;
• or RX and RY are joined together to form a 3-10 membered heterocyclic ring;
• R19 is hydrogen or alkyl;
• R5 is absent or hydrogen;
• a is 0;
• and
• represents a single or double bond, wherein when one is a double bond, the other is a single bond and R5 is absent.