[ A series of new benzoylquinoxaline derivatives (7-26) was synthesized and evaluated for antitumor activity against a panel of 60 human cell lines at the NO of Bethesda. Among the compounds which have passed the preliminary screening, compound 23 exhibited the best profile and growth inhibition activity at 100-10 mu M. The compounds were then tested towards a folate-dependent enzymes bio-library including Thymidylate synthases enzymes and human Dihydrofolate reductase at 10 mu M. The most of compounds exhibited a moderate inhibitory activity towards all or some of the enzymes tested with detectable inhibition constants (K-i) values in the range of 0.6-70 mu M. Compounds 21, 23, 24 showed K-i in the range of 10-38 mu M against both hDHFR and hTS.