Compounds and uses thereof

1. A compound having the structure of Formula I:

wherein

B is

optionally substituted C 2 -C 9 heteroaryl, or C 2 -C 9 heterocyclyl;

R is

wherein R 1 is optionally substituted C 1 -C 3 alkyl or optionally substituted C 3 -C 6 cycloalkyl;

each R 3 and R 5 is, independently, selected from the group consisting of H, optionally substituted C 1 -C 6 alkyl, or optionally substituted C 1 -C 6 heteroalkyl;

R 4 is hydrogen, or optionally substituted C 1 -C 6 heteroalkyl; and

R 6 is optionally substituted C 6 -C 10 aryl or optionally substituted C 2 -C 9 heteroaryl

or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1 , wherein the compound has the structure

wherein R 1 is optionally substituted C 1 -C 3 alkyl,

or a pharmaceutically acceptable salt thereof.

3. A compound having the structure of any one of compounds

and pharmaceutically acceptable salts thereof.

4. A pharmaceutical composition comprising the compound of claim 1 and a pharmaceutically acceptable excipient.

5. The compound of claim 1 , wherein both R 3 and R 5 are H.

6. The compound of claim 1 , wherein R 4 is H,