Histone deacetylases inhibitors (HDACIs) and methods for treating cancer in a subject in need thereof are disclosed. The HDACIs comprise a compound of Formula X.
or a pharmaceutically acceptable salt thereof. In one embodiment of the invention, R1 is ethyl; R2 is 2-phenylethyl; R3 is hydrogen; R4 is fluoro; R5 is (2E)-3-N-hydroxyamino-3-oxo-propenyl; and R6 is hydrogen, or a salt thereof. In another embodiment of the invention, R1 is ethyl; R2 is 2-phenylethyl; R3 is hydrogen; R4 is (2E)-3-N-hydroxyamino-3-oxo-propenyl; R5 is chloro or fluoro; and R6 is hydrogen.
Histone deacetylases inhibitors (HDACIs) and compositions comprising the same are disclosed. Methods of treating diseases and conditions wherein inhibition of HDAC provides a benefit are also disclosed.