Patent ID: 8735441

Claim:
A compound having a structure of formula (I) or a pharmaceutically acceptable salt thereof, wherein B is absent; L is C═O; Q is absent or is selected from O, NH, and N—C 1-6 alkyl; X is O; R 1 is selected from H, —C 1-6 alkyl-B, C 1-6 hydroxyalkyl, C 1-6 alkoxyalkyl, aryl, and C 1-6 aralkyl; R 2 and R 3 are each independently selected from aryl, C 1-6 aralkyl, heteroaryl, and C 1-6 heteroaralkyl; R 4 is N(R 5 )L-Q-R 6 ; R 5 is selected from hydrogen, OH, C 1-6 aralkyl, and C 1-6 alkyl; R 6 is selected from hydrogen and substituted or unsubstituted C 1-6 alkyl, wherein each substituent is selected from the group consisting of: a halogen, a hydroxyl, a carbonyl, a thiocarbonyl, an alkoxyl, a phosphoryl, a phosphate, a phosphonate, a phosphinate, an amino, an amido, an amidine, an imine, a cyano, a nitro, an azido, a sulfhydryl, an alkylthio, a sulfate, a sulfonate, a sulfamoyl, a sulfonamido, and a sulfonyl; R 7 and R 8 are independently selected from hydrogen, C 1-6 alkyl, and C 1-6 aralkyl; and R 15 is C 1-6 alkyl.