Synthesis of ETP derivatives

A method for converting a ring bridging trisulfide compound to a ring bridging disulfide compound, comprising combining the ring bridging trisulfide compound with a non-nucleophilic base, thereby affording the corresponding ring bridging disulfide compound, wherein the ring bridging trisulfide compound is of formula (Ia):

• and the ring bridging disulfide compound is of formula (Ib):
• wherein:
• R1 is hydrogen, halogen, —N3, —CF3, —CCl3, —CBr3, —CI3, —CN, —CHO, —OR33A, —NR34AR35A, —COOR33A, —CONR34AR35A, —NO2, —SR36A, —SOn1R34A, —SOn1OR34A, —SOn1NR34AR35A, —NHNR34AR35A, —ONR34AR35A, —NHC(O)NHNR34AR35A, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl,
• R2 is hydrogen, halogen, —N3, —CF3, —CCl3, —CBr3, —CI3, —CN, —CHO, —OR33B, —NR34BR35B, —COOR33B, —CONR34BR35B, —NO2, —SR36B, —SOn2R34B, —SOn2OR34B, —SOn2NR34BR35B, —NHNR34BR35B, —ONR34BR35B, —NHC(O)NHNR34BR35B, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl;
• R3 is hydrogen, halogen, —N3, —CF3, —CCl3, —CBr3, —CI3, —CN, —CHO, —OR33C, —NR34CR35C, —NR34CR35C, —COOR33C, —CONR34CR35C, —NO2, —SR36C, —SOn3R34C, —SOn3OR34C, —SOn3NR34CR35C, —NHNR34CR35C, —ONR34CR35C, —NHC(O)NHNR34CR35C, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl;
• R4 is hydrogen, halogen, —N3, —CF3, —CCl3, —CBr3, —CI3, —CN, —CHO, —OR33D, —NR34R35D, —COOR33D, —CONR34DR35D, —NO2, —SR36D, —SOn4R34D, —SOn4OR34D, —SOn4NR34DR35D, —NHNR34DR35D, —ONR34DR35D, —NHC(O)NHNR34DR35D, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl;
• R5 is hydrogen, halogen, —N3, —CF3, —CCl3, —CBr3, —CI3, —CN, —CHO, —OR33E, —NR34ER35E, —COOR33E, —CONR34ER35E, —NO2, —SR36E, —SOn5R34E, —SOn5OR34E, —SOn5NR34ER35E, NHNR34ER35E, —ONR34ER35E, —NHC(O)NHNR34ER35E substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl;
• R6 is hydrogen, halogen, —N3, —CF3, —CCl3, —CBr3, —CI3, —CN, —CHO, —OR33F, —NR34FR35F, —COOR33F, —CONR34FR35F, —NO2, —SR36F, —SOn6R34F, —SOn6OR34F, —SOn6NR34FR35F, NHNR34FR35F, —ONR34FR35F, —NHC(O)NHNR34FR35F, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl;
• R16 is hydrogen, halogen, —N3, —CF3, —CCl3, —CBr3, —CI3, —CN, —CHO, —OR33G, —NR34GR35G, —COOR33G, —CONR34GR35G, —NO2, —SR36G, —SOn7R34G, —SOn7OR34G, —SOn7NR34GR35G, NHNR34GR35G, —ONR34GR35G, —NHC(O)NHNR34GR35G, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl;
• R18 is hydrogen, halogen, —N3, —CF3, —CCl3, —CBr3, —CI3, —CN, —CHO, —OR33H, —NR34HR35H, —COOR33H, —CONR34HR35H, —NO2, —SR36H, —SOn8R34H, —SOn8OR34H, —SOn8NR34HR35H, —NHNR34HR35H, —ONR34HR35H, —NHC(O)NHNR34HR35H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl;
• R33A, R34A, R35A, R36A, R33B, R34B, R35B, R36B, R33C, R34C, R35C, R36C, R33D, R34D, R35D, R36D, R33E, R34E, R35E, R36E, R33F, R34F, R35F, R36F, R33G, R34G, R35G, R36G, R33H, R34H, R35H, and R36H are independently hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl;
• and
• n1, n2, n3, n4, n5, n6, n7, and n8 are independently 1 or 2.