A compound according to claim 12, wherein R3 is H or methyl, R4 is OH or NH2, and R2 is a substituent independently selected from H, hydroxy], C-,-C6 alkoxy, Ct-C6 haloalkyi, NRnR-12 wherein Rn and R 2 are independently selected from H and C C6 alkyl, and R9 is H or C C10 alkyl. 14.