Synthesis, Molecular Docking and Biological Evaluation of Some New Benzotriazines

Methyl 2-(4-oxobenzotriazin-3(4H)-yl) alkanoates4a-c proved to be important intermediates for the preparation of some biologically interesting compounds containing the benzotriazinone ring system. Esters 4a-c were prepared by direct diazotization of methyl anthranilate followed by addition of amino acid esters hydrochloride in a one-pot strategy. An equivocal synthesis of methyl 2-(4-oxobenzotriazin-3(4H)-yl) acetate 4a was achieved by alkylation of benzotriazin-4(3H)one with methyl chloroacetate on the basis of chemoselective reaction of heterocyclic amide with electrophiles. A series of N-alkyl-2-(4-oxobenzotriazin-3(4H)-yl) alkanamides7-8(a-h) and methyl 2-(2-(4-oxobenzotriazin-3(4H)-yl)alkanamido)alkanoates (dipeptides) 9-10(a-d) were prepared via azide coupling from 4a-b. Esters 4a-b were converted into the corresponding hydrazides followed by condensation with aldehydes; 4-methoxybenzaldehyde, 4-dimethylamino benzaldehyde and arabinose to afford the corresponding hydrazone derivatives11-13. All the synthesized compounds were subjected to the molecular docking using MOE 2008-10 software as agonist for; E. coli Fab-H receptor and Vitamin D receptor for antibacterial and anticancer evaluation, respectively. The most pronounced strong binding affinity towards the target E. coli Fab-H receptor were compounds 7a, 11a, 11b,10a,10cand 12b. On the other hand, the most pronounced strong binding affinity towards the target Vitamin D receptor were compounds 3, 9c, 11a and 10d. The in vitro antibacterial activity of highest binding affinity docked compounds were tested against E. coli, Staphylococcus aureus and Salmonella spp. All the tested compounds gave effective positive results against E. coli with inhibitory zone of about 1.1 cm, while were inactive against Staphylococcus aureus and Salmonella spp. The in vitro cytotoxic activity of the highest binding affinity docked compounds were tested against human liver carcinoma cell line (HepG2) cancer cell lines. Many compounds showed potent cytotoxic activity with low IC₅₀ values, especially for 3(6.525µM) and 11a (10.97 µM), while for standard drug doxorubicin (5.8 µM).