Synthesis and biological activity of new 2-amino-8-chloro-5,5-dioxo[1,2,4]triazolo[2,3-b][1,4,2]benzodithiazines.

Two series of 1-(6-chloro-1,1-dioxo-1,4,2-benzodithiazin-3-yl)-4-arylsemicarbazides 6-17 and 2-arylamino-8-chloro-5,5-dioxo[1,2,4]triazolo[2,3-b][1,4,2]benzodithiazines 18-26 were prepared in order to evaluate their biological activity. Compounds 6 and 18-26 were tested for their in vitro cytotoxic potency against 12 human cancer cell lines. The compounds 6 and 19 were inactive, whereas triazolobenzodithiazines 18, 20-26 possess tumor growth inhibitory properties. The prominent methyl 8-chloro-2-(4-chlorophenylamino)-5,5-dioxo[1,2,4]triazolo[2,3-b][1,4,2]benzodithiazine-7-carboxylate (21) exhibited potency higher or comparable to cisplatin. Moreover, compounds 6, 9, 19 and 23-25 with structure similar to other chemotherapeutic agents were tested for their antibacterial activity and exhibited MIC and MBC against Staphylococcus aureus (3.9-31.5 microg ml).