A series of pyridines, pyrimidinones, oxazinones and their derivatives were synthesized as antimicrobial agents using citrazinic acid (2,6-dihydroxyisonicotinic acid) as a starting material. α,β-Unsaturated ketones 3a–c were condensed with cyanothio-acetamide in the presence of ammonium acetate to give 2-cyanopyridinethiones 4a–c, which were reacted with ethyl chloroacetate to yield the corresponding cyano esters 5a–c. The esters 5a–c were cyclized by action of sodium methoxide to aminoesters 6a–c, which were aminolyzed with ammonia to corresponding aminoamide derivatives 7a-c. Also, the esters 6a–c were hydrolyzed with NaOH to the corresponding sodium salt 8a–c, which were treated with acetic anhydride to afford 2-methyloxazinones 9a–c. The latter compounds were treated with ammonium acetate to afford 2-methylpyrimidinones 10a–c, followed by methylation with methyl iodide to yield 2,3-dimethyl-pyrimidinones 11a–c. The antimicrobial screening showed that many of these compounds have good antibacterial and antifungal activities comparable to streptomycin and fusidic acid used as reference drugs.

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A series of novel coumarin derivatives carrying 1,2,4-triazole or 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole moieties were prepared and evaluated in vitro as anticancer in the human colon cancer (HCT116) cell line. The derivatives 4c and 8c exhibited marked anticancer activity with IC50 values 4.363 and 2.656 µM, respectively. The molecular docking studies suggested possible interaction with tyrosine kinases (CDK2).