Five-member thio-heterocyclic fused naphthalimides with aminoalkyl side chains: intercalation and photocleavage to DNA.

Novel five-member thio-heterocyclic fused naphthalimides with aminoalkyl side chains were designed, synthesized and evaluated. These compounds have high Scatchard binding constants. They could damage DNA (supercoiled pBR322) from form I (closed) to II (nicked) at a concentration as low as 10 microM and from form I to form III at a concentration of 50 microM. The results implied that the influence of intercalating ability of chromophores on photocleaving ability of photocleavers depended on the mechanism of photocleavage.