Highly efficient antitumor agents of heterocycles containing sulfur atom: linear and angular thiazonaphthalimides against human lung cancer cell in vitro

A novel series of aminothiazonaphthalimides, A(1-2) and B(1-2), has been regioselectively synthesized. The linear compounds B(1-2) were evaluated to be far more active than their angular isomers A(1-2) in antitumor evaluation. The linear compounds C-F, derived from compound B(1), all showed highly efficient antitumor activities against A549 and P388 cell lines. Also, cytotoxicities of these four analogues against two tumor cells were highly dependent on the length of the side chains. The compound A(1) or B(1), with two methylene units in the side chain, was more cytotoxic than its corresponding homologue A(2) or B(2), with one more methylene unit.