Thiobase compounds for photodynamic therapy

A method of treating cancer or a cancer-associated disorder in a subject in need thereof, the method comprising:

• administering to a subject in need of treatment a therapeutically effective amount of compound having the formula:
• or pharmaceutically acceptable salts thereof;
• wherein R1 is H, OH, ribose, deoxyribose, amino acid residue(s), fatty acid residue(s), ORa, where Ra comprises at least one of a straight chain, branched or cyclic alkyl, CO-alkyl, CO-aryl, CO-alkoxyalkyl, arylsulfonyl, or aralkylsulfonyl, or a mono, di, or triphosphate thereof,
• R2 and R3 are independently the same or different and are each selected from the group consisting of a H, F, Cl, Br, I, a lower alkyl group, (CH2)n1OR′ (wherein n1=1, 2, or 3), CF3, CH2—CH2X, O—CH2—CH2X, CH2—CH2—CH2X, O—CH2—CH2X (wherein X═F, Cl, Br, or I), CN, (C═O)—R′, N(R′)2, NO2, (C═O)N(R′)2, O(CO)R′, OR′, SR′, COOR′ (wherein R′ is H or a lower alkyl group), or a substituted or unsubstituted aryl, heteroaryl, cycloalkyl, or heterocyclyl, and wherein R2 and R3 if present may be linked to form a cyclic or polycyclic ring, wherein the ring is a substituted or unsubstituted aryl, heteroaryl, cycloalkyl, or a heterocyclyl;
• and
• exposing the administered compound to electromagnetic radiation effective to treat the cancer or cancer-associated disorder.