Steroids and protein-conjugates thereof

A compound of Formula (A):

• or a pharmaceutically acceptable salt, solvate, or stereoisomer thereof, wherein:
• R1 and R2 together form
• wherein R4 is linear or branched alkyl, aryl, arylalkyl, or an N-containing heterocycloalkyl,
• wherein the alkyl, aryl, arylalkyl, and N-containing heterocycloalkyl are, independently in each instance, optionally substituted with —NRcRd,
• wherein Rc and Rd are, independently in each instance, —H, alkyl, or optionally substituted aryl;
• R3 is —NRaRb,
• wherein Ra and Rb are, independently in each instance, —H, alkyl, or optionally substituted aryl;
• R5 is, independently in each instance, —OH, halo, alkyl, or arylalkyl;
• and
• n is an integer from 0-19.