Patent ID: 7799776

Claim:
A compound of formula VI or a pharmaceutically acceptable salt thereof, wherein, X 1 and X 2 are independently selected from: H, R, OH, OR, F, Cl, Br, I, NH 2 , NHR, NR 2 , CN, SH, SR, SO 3 H, SO 3 R, SO 2 R, OSO 3 R, and NO 2 in which R is an optionally substituted saturated or unsaturated linear, branched, or cyclic alkyl group or optionally substituted aryl group, wherein optional substituents are optionally selected from the groups consisting of aryl, ether, amino, hydroxy, ester, thioether, thiol, nitrile, nitro, amide, carbonyl, carboxyl, carboxylate, and halide groups; R 15 and R 16 are individual substituents independently selected from: H, OH, OR, and a linear, branched, or cyclic, saturated or unsaturated alkyl group in which one or more carbon atoms of the alkyl group are optionally and independently substituted or are replaced by an oxygen (O) or sulfur (S) atom or a secondary amino (NR) group, where R is as defined above; or R 15 and R 16 are fused and form a substituted or unsubstituted, aromatic or non-aromatic, mono-, bi-, or tri-cyclic ring system containing C, O, N or S atoms; excluding a compound having the structure: