PROTEOLYSIS TARGETING CHIMERA (PROTAC) COMPOSITIONS USING UBIQUITIN CONJUGATING ENZYME LIGANDS

1 . A compound comprising an E2 binding moiety, a target protein binding moiety, and a linker (L) which covalently attaches the E2 binding moiety to the target protein binding moiety.

2 . The compound of claim 1 , wherein the E2 binding moiety is selected from one that binds an E2 enzyme selected from UBE2A, UBE2B, UBE2C, UBE2D1, UBE2D2, UBE2D3, UBE2D4, UBE2E1, UBE2E2, UBE2E3, UBE2G1, UBE2G2, UBE2H, UBE2J1, UBE2J2, UBE2K, UBE2L3, UBE2N, UBE2NL, UBE2O, UBE2Q1, UBE2Q2, UBE2QL, UBE2R1, UBE2R2, UBE2S, UBE2T, UBE2U, UBE2V1, UBE2V2, UBE2W, and BIRC6.

3 . The compound of claim 1 , wherein the E2 binding moiety is one that binds UBE2K.

4 . The compound of claim 1 , wherein the E2 binding moiety is a compound of the Formula I:

wherein

Z 1 and Z 2 are each independently N or CH:

R 1 is (C 1 -C 6 )alkyl, halo(C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, halo(C 1 -C 6 )alkoxy, or —NR c R d , wherein two available hydrogen atoms on said halo(C 1 -C 6 )alkyl and halo(C 1 -C 6 )alkoxy may be taken together to which the carbon atoms they are attached to form a 3- to 6-membered cycloalkyl optionally substituted with 1 to 3 groups selected from halo, (C i -C W )alkyl, halo(C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, and halo(C 1 -C 6 )alkoxy;

R 2 is CN, halo, OH, (C 1 -C 6 )alkyl, halo(C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, or halo(C 1 -C 6 )alkoxy; or R 1 and R 2 , when on adjacent carbon atoms, are taken together with the carbon atoms to which they are attached to form a 5- or 6-membered oxygen containing heterocyclyl optionally substituted with 1 to 3 groups selected from halo, (C 1 -C 6 )alkyl, and halo(C 1 -C 5 )alkyl;

R 3 is hydrogen, (C 1 -C 6 )alkyl, or halo(C 1 -C 5 )alkyl;

Y is CH 2 , —CHR a , —CR a R b , S, or SO;

p is 0 or 1,

R a and R b are each independently halo, (C 1 -C 6 )alkyl, or halo(C 1 -C 6 )alkyl; or R a and Rh together with the carbon atom they are bound for a 3- to 6-membered cycloalkyl or a 3- to 6-membered heterocyclyl, each of which are optionally substituted with 1 to 3 groups selected from halo, (C 1 -C 6 )alkyl, halo(C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, halo(C 1 -C 5 )alkoxy, (C 1 -C 6 )alkylOH, (C 1 -C 6 )alkyl(C 1 -C 6 )alkyl, and OH;

R c and R d are each independently hydrogen (C 1 -C 5 )alkyl, halo(C 1 -C 6 )alkyl, (C 1 -C 6 )alkyl(C 1 -C 6 )alkyl, halo(C 1 -C 6 )alkyl(C 1 -C 5 )alkyl, (C 1 -C 6 )alkyl-O-halo(C 1 -C 5 )alkyl, halo(C 1 -C 6 )alkyl-O-halo(C 1 -C 6 )alkyl, or (C 1 -C 6 )alkylOH, or R c and R d together with the nitrogen atom they are bound form a 4- to 7-membered heterocyclyl optionally substituted with 1 to 3 groups selected from halo, (C 1 -C 6 )alkyl, halo(C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, halo(C 1 -C 6 )alkoxy, and oxo;

Z is a tricyclic fused ring having the formula:

ring A is aromatic;

the wavy bond on ring A denotes the point of attachment to Y:

the wavy bond next to W denotes the point of attachment to Linker (L);

X, X 1 , and X 2 are each, as valency permits, independently selected from —CR 7 , N, O, and S;

the dotted line in ring B represents a single or double bond;

W is NH, —N(C 1 -C 6 )alkyl), O, or S;

R 5 is selected from hydrogen, (C 1 -C 5 )alkyl, halo(C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, halo(C 1 -C 6 )alkoxy, —S(C 1 -C 6 )alkyl, —SH, OH, (C 3 -C 7 )cycloalkyl, (C 4 -C 7 )heterocyclyl, and —NR e R f , wherein said (C 3 -C 6 )cycloalkyl and (C 4 -C 7 )heterocyclyl are each optionally substituted with 1 to 3 groups selected from halo, (C 1 -C 6 )alkyl, halo(C 1 -C 6 )alkyl, (C 1 -C 6 )alkoxy, halo(C 1 -C 6 )alkoxy, and oxo;

R 6 is hydrogen or (C 1 -C 6 )alkyl when the dotted line in ring B is a single bond, or R 6 is absent when the dotted line in ring B is a double bond;

d, d 1 , d 2 and d 3 are each independently selected from CR 8 and N:

R e and R f are each independently hydrogen, (C 1 -C 4 )alkyl, (C 1 -C 4 )alkylNHC(C 1 -C 6 )alkyl, (C 1 -C 4 )alkylNHC(C 1 -C 4 )alkylN, (C 1 -C 4 )alkylO(C 1 -C 4 )alkyl;

R 7 is hydrogen or (C 1 -C 6 )alkyl; and

R 8 is halogen, hydrogen, (C 1 -C 6 )alkyl, halo(C 1 -C 6 )alkyl, CN or OH.

5 . The compound of claim 4 , wherein the E2 binding moiety is a compound of the Formula 1:

6 . The compound of claim 5 , wherein

W is S;

R 3 is hydrogen;

Z 1 and Z 2 are each CH:

Y is CH 2 ;

R 1 is C 1 -C 6 )alkyl, halo C 1 -C 6 )alkyl halo C 1 -C 6 ) alkoxy, C 1 -C 6 )alkoxy, or —NR e R d and R c and R d together with the nitrogen atom they are bound form a 5- to 6-membered heterocyclyl optionally substituted with 1 to 3 halo:

X is N:

X 1 is CH or N:

X 2 is CH, N, S, or O;

d is N or —CR 8

d 2 is N or —CR 8 :

d 1 is —CR 8 ; and

d 3 is —CR 8 .

7 - 21 . (canceled)

22 . The compound of claim 6 , wherein Z is selected from

23 . The compound of claim 6 , wherein Z is selected from

24 . The compound of claim 23 , wherein

R 8 is hydrogen or halo;

R 5 is hydrogen; and

R 6 is selected from hydrogen and (C 1 -C 6 )alkyl.

25 - 28 . (canceled)

29 . The compound of claim 1 , wherein the E2 binding moiety is a compound of the Formula III:

wherein

d, d 1 , d 2 and d 3 are each CR 8 ;

p is 0; and

Z is S.

30 . (canceled)

31 . (canceled)

32 . The compound of claim 1 , wherein the E2 binding moiety is of the structure:

33 . The compound of claim 1 , wherein the target protein binding moiety is one that binds a protein selected from STAT3, BCL2, WRN and BRD4.

34 . (canceled)

35 . The compound of claim 1 , wherein the target protein binding moiety is of the structure:

wherein the wavy bond denotes the point of attachment to Linker (L).

35 . The compound of claim 1 , wherein linker (L) comprises an optionally substituted straight or branched alkyl group which is optionally interrupted by one or more heteroatoms selected from 0, N, and S.

36 . (canceled)

37 . The compound of claim 1 , wherein Linker (L) is of the following structure:

wherein the asterisk (*) denotes the point of attachment to the E2 binding moiety; e is an integer from 0 to 4; and j is an integer from 0 to 6.

38 - 40 . (canceled)

41 . The compound of claim 1 , wherein the compound is of the structural formula:

or a pharmaceutically acceptable salt thereof.

42 . A pharmaceutical composition comprising the compound of claim 1 , or a pharmaceutically acceptable salt thereof; and a pharmaceutically acceptable carrier.

43 . A method of treating a disease responsive to degradation of a target protein comprising administering to the subject an effective amount of a compound of claim 1 .

44 . The method of claim 43 , wherein the target protein is selected from STAT3, BCL2, WRN, and BRD4.

45 . The method of claim 43 , wherein the disease is selected from a cancer, an inflammatory disease, sepsis, an autoimmune disease, and a viral infection.