Patent ID: 8410130

Claim:
A compound of formula I, II, III, or IV: and pharmaceutically acceptable salts and mixtures thereof, wherein: R 1 is chosen from hydrogen, a C 1 -C 5 linear or branched alkyl group, an aryl, and a benzyl, which may be unsubstituted or substituted; R 2 , R 3 , R 4 and R 5 are independently chosen from hydrogen, C 1 -C 6 alkyl, OR a , halo, cyano, nitro, NH 2 , NHR b , and N(R b ) 2 , wherein R a is chosen from hydrogen and C 1 -C 10 alkyl, and R b is chosen from hydrogen and C 1 -C 10 alkyl; and R 6 is chosen from a saturated or unsaturated, linear or branched, C 1 -C 5 alkyl group, an unsubstituted or substituted phenyl group, and an unsubstitued or substituted benzyl group, and further wherein: when the C 1 -C 5 linear or branched alkyl group is substituted, one or more substituents are independently chosen from halogen, hydroxy, alkoxy, lower alkyl, lower alkenyl, and lower alkynyl; and when the aryl, the benzyl, or the phenyl group is substituted, one or more substituents are independently chosen from C 1 -C 6 alkyl, OR a , halo, cyano, nitro, NH 2 , wherein R a is as defined above.