Synthesis of Some New Substituted Pyridilimides From 2-Carboxy Nicotinic Acid By Reaction With Amines, and Evaluation of Their Antibacterial Activity

In this paper, we synthesized some new substituted pyridilimides in three different ways. Firstly, by the reaction of 2-carboxy nicotinic acid with some amino acids to form 2-substituted (5,7-dioxo-5,7-dihydro-6H-pyrrolo [3,4-b] pyridine-6-yl) acetic acid (1–2). In the next step, the resultant compounds were treated with phenylene diamine to form substituted 6-((1H-benzo[d]imidazol-2-yl) methyl)-5H-pyrrolo [3,4-b] pyridine-5,7(6H)-dione (3-4). Secondly, 2-carboxy nicotinic acid, which was converted to anhydride (5), reacted with acetic anhydride and acetic acid. In the next step, two moles of (5) were used to react with some aliphatic or aromatic diamine to give substituted bis 5H-pyrrolo [3,4-b] pyridine-5,7(6H)-dione (6–11). Finally, (5) was treated with urea to form imide (12). The next step, imide (12) was treated with formaldehyde to give 6-(hydroxymethyl)-5H-pyrrolo [3,4-b] pyridine-5,7(6H)-dione (13). The next step was to react (13) with substituted aniline to form substituted 6-((phenylamino)methyl)-5H-pyrrolo [3,4-b] pyridine-5,7 (6H)-dione (14-17). The resulting compounds were proven by their physical properties and by IR, 1H-NMR, and CHN. The antibacterial assessment of many compounds produced to fight two pathogenic bacterial strains was carried out, and the outcomes were contrasted with two well-known antibiotics. Compounds (1, 8, 17) showed a high inhibition zone (20, 16, 19) mm respectively. Docking was carried out using CB-Dock2 against the shikimate kinase enzyme, where compound (8) had the highest docking score of -8.6 Kcal/mol. This result encourages the synthesis of more substituted pyrrolopyridin compounds as a future work.