Synthesis of New Dihydropyrimidine-2-Thione Derivatives and Their Antibacterial Screening

In this work, we reported the synthesis of new dihydropyrimidine-2-thione derivatives 5a-h. The reaction intermediates of these derivatives are chalcones or 1,3-diarylprop-2-en-1-one derivatives 3a-h, synthesized from acetophenone and various aldehydes which have not yet been used for the synthesis of dihydropyrimidine-2-thiones. All sixteen (16) compounds synthesized were characterized by 1H and 13C NMR. The three (3) bacterial strains tested on the synthesized compounds were Staphylococcus aureus, Klebsiella aerogenes formerly called Enterobacter aerogenes and Pseudomonas aeruginosa. Antibacterial activity was evaluated using the agar diffusion method with a sterile disc impregnated by the compound tested at three concentrations C1 (12.5 mg/mL), C2 (6.25 mg/mL) and C3 (3.12 mg/mL). The antibiotics used as references were cefoxitin, fusidic acid, ceftazidime, imipenem and pefloxacin. Compounds 3g, 3h, 5b, 5d and 5f revealed antibacterial activity only against the Staphylococcus aureus strain.