Synthesis, Characterization and Antibacterial Evaluation of 2, 3Dihydroquinazolin-4 (1H)-Ones and Some New Bis 2, 3- Dihydroquinazolin-4 (1H)-Ones Using Pre-made Pyrazole Carbaldehyde Derivatives

2, 3-Dihydroquinazolinones are of popular compounds with the diversification of biological and pharmacological activities. Among many discovered methods, there are efficient and convenient methods used for the synthesis of 2, 3-dihydroquinazoline-4 (1H)-one and some new bis 2, 3- dihydroquinazoline-4 (1H)-one derivatives which are reported in this study. The mentioned methods include the two-component condensation of one molecule of anthranilamide and one molecule of pyrazole carbaldehyde using montmorillonite-K10 as a catalyst for the preparation of 2, 3 dihydroquinazoline-4 (1H)-ones. Also, one-pot pseudo-five-component reaction (5MCRs) of two molecules of isatoic anhydride, two molecules of pyrazole carbaldehydes and one molecule of ethan-1, 2-diamine in the presence of the r catalyst (montmorillonite-K10) for the synthesis of bis 2, 3-dihydroquinazoline-4 (1H)-ones. Despite the short times of reactions, high yields of products were obtained, which were validated using FT-IR, ¹HNMR, ¹³CNMR, and elemental analysis. Moreover, the compounds were screened for their antimicrobial activities against two-gram-positive bacterial strains: Staphylococcus aureus and Micrococcus Luteus; and against two-gram-negative bacterial strains, as well: Escherichia coli and Pseudomonas aeruginosa, which all were utilized for antibacterial investigations. The results showed moderate or significant antibacterial activities.