Utility of anthranilic acid and diethylacetylenedicarboxylate for the synthesis of nitrogenous organo/organometallic compounds as urease inhibitors.

Fumarate diester 3 was synthesized upon reacting anthranilic acid with diethylacetylenedicarboxylate. Compound 3 was reacted with different nucleophiles in mild reaction conditions. Selected reaction routes that afforded products 6, 9, 10, 11, and 12 were explained. The estimated mechanism for the reaction of 3 with ethylenediamine to afford 9 was proved by X-ray single-crystal and retro-synthetic reaction. Acetyl anthranilic acid was utilized with zinc and copper to afford the organometallic compounds 14a and 14b, respectively. Three single crystals were afforded for 3, 9 and the organocopper complex 14b. Target compounds were screened for their inhibitory potential against urease enzyme. Most compounds were more potent than thiourea as standard inhibitor, considering that oxopiperazine 9 exhibited double the activity: IC50 = 8.16 ± 0.65 µM (thiourea IC50 = 20.04 ± 0.33 µM). Docking studies were in agreement with the in vitro enzyme assay.