Trimethylbenzoquinone (Compound 5) is a methylated benzoquinone. Trimethylbenzoquinone exhibits moderate cytotoxicity against K562 cells, with its IC50 being 0.75 μM. Trimethylbenzoquinone is completely unable to cause inter-strand DNA cross-linking and cannot alkylate DNA guanines. Trimethylbenzoquinone can be used to study the relationship between the nitrogen heterocyclic group and DNA cross-linking[1].