Patent ID: 7655640

Claim:
A method of inhibiting topoisomerase I mediated DNA cleavage in a mammal, comprising: administering to the mammal a pharmaceutically effective amount of a compound having the following formula or a pharmaceutically acceptable salt thereof: wherein R 1 and R 2 are independently the same or different and are hydrogen, an alkyl group, an aminoalkyl group, an alkylaminoalkyl group, a C 1 -C 3 perphaloalkyl group, hydroxyalkyl group an alkenyl group, an alkynyl group, an alkoxyl group, an aryloxy group, a carbamoyloxy group, a halogen, a hydroxyl group, a nitro group, a cyano group, an azido groups a formyl group, a hydrazino group, —C(O)R f , wherein R f is an alkyl group, a haloalkyl group, an alkoxyl group, an amino group or a hydroxyl group, an amino group, an alkylamino group, a dialkylamino group, —SR c , wherein R c is hydrogen, —C(O)R f , an alkyl group, or an aryl group, —OC(O)R d or —OC(O)OR d , wherein R d is an alkyl group; or R 1 and R 2 together form a group of the formula —O(CH 2 ) n O— wherein n represents the integer 1 or 2; R 3 is H, F, a halogen atom, a nitro group, an amino group, a hydroxyl group, or a cyano group; or R 2 and R 3 together form a group of the formula —O(CH 2 ) n O— wherein n represents the integer 1 or 2; R 4 is H, F, a C 1-3 alkyl group a C 2-3 alkenyl group, a C 2-3 alkynyl group, or a C 1-3 alkoxyl group; R 5 is a C 1-10 alkyl group, or a propargyl group; and R 6 , R 7 and R 8 are independently a C 1-10 alkyl group, a C 2-10 alkenyl group, a C 2-10 alkynyl group, an aryl group or a —(CH 2 ) N R 9 group, wherein N is an integer within the range of 1 through 10 and R 9 is a hydroxyl group, alkoxy group, an amino group, an alkylamino group, a dialkylamino group, a halogen atom, a cyano group or a nitro group; provided that at least one of R 1 , R 2 , R 3 and R 4 is not H, a halogen, an alkyl group, an amino group or a nitro group.