A compound of Formula I or a pharmaceutically acceptable salt thereof, wherein: R 1, R 2, R 3, R 5, R 6, R 9, R 10, R 11 and R 12 are independently chosen from hydrogen, hydroxy, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted heteroaryloxy, optionally substituted heterocycloalkyloxy, optionally substituted aminocarbonyloxy, optionally substituted acyloxy, optionally substituted alkoxycarbonyloxy, and optionally substituted amino; or R 1 and R 2, or R 5 and R 6, or R 9 and R 10, or R 11 and R 12 mutually independently, together in each case denote an oxo group (=O); R 4 is hydroxy, or R 4 and R 5 may optionally be joined together with any intervening atoms to form an optionally substituted heterocycloalkyl ring; R 7 is -OCOCH 3; R 8 is chosen from hydrogen, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, and optionally substituted alkynyl; R 13 is chosen from hydrogen, optionally substituted alkyl, and formyl; Z is NR 15 R 16; wherein R 15 and R 16 are joined together with any intervening atoms to form an optionally substituted heterocycloalkyl ring; W 1 is chosen from the following moieties: wherein Y is chosen from O and NR 18; R 17 is chosen from cyano, halo, hydroxy, azido, nitro, carboxy, sulfinyl, sulfanyl, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted heteroaryloxy, optionally substituted heterocycloalkyloxy, optionally substituted alkoxycarbonyl, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted aryloxy, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocycloalkyl, optionally substituted amino, optionally substituted acyl, optionally substituted alkoxycarbonyl, optionally substituted aminocarbonyl, optionally substituted aminosulfonyl, optionally substituted carbaminodoyl, and optionally substituted alkynyl; R 18 is chosen from hydrogen, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, and optionally substituted heteroaryl; W 2 is chosen from hydrogen, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, and optionally substituted alkynyl; m is selected from 0, 1, 2, and 3; n is selected from 0 and 1, and the dotted line represents a single bond or a double bond. R 1, R 2, R 3, R 5, R 6, R 9, R 10, R 11 and R 12 are independently chosen from hydrogen, hydroxy, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted heteroaryloxy, optionally substituted heterocycloalkyloxy, optionally substituted aminocarbonyloxy, optionally substituted acyloxy, optionally substituted alkoxycarbonyloxy, and optionally substituted amino; or R 1 and R 2, or R 5 and R 6, or R 9 and R 10, or R 11 and R 12 mutually independently, together in each case denote an oxo group (=O); R 4 is hydroxy, or R 4 and R 5 may optionally be joined together with any intervening atoms to form an optionally substituted heterocycloalkyl ring; R 7 is -OCOCH 3; R 8 is chosen from hydrogen, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, and optionally substituted alkynyl; R 13 is chosen from hydrogen, optionally substituted alkyl, and formyl; Z is NR 15 R 16; wherein R 15 and R 16 are joined together with any intervening atoms to form an optionally substituted heterocycloalkyl ring; W 1 is chosen from the following moieties: wherein Y is chosen from O and NR 18; R 17 is chosen from cyano, halo, hydroxy, azido, nitro, carboxy, sulfinyl, sulfanyl, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted heteroaryloxy, optionally substituted heterocycloalkyloxy, optionally substituted alkoxycarbonyl, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted aryloxy, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocycloalkyl, optionally substituted amino, optionally substituted acyl, optionally substituted alkoxycarbonyl, optionally substituted aminocarbonyl, optionally substituted aminosulfonyl, optionally substituted carbaminodoyl, and optionally substituted alkynyl; R 18 is chosen from hydrogen, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted aryl, and optionally substituted heteroaryl; W 2 is chosen from hydrogen, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, and optionally substituted alkynyl; m is selected from 0, 1, 2, and 3; n is selected from 0 and 1, and the dotted line represents a single bond or a double bond.