Antimicrobial and antiquorum-sensing studies. Part 2: synthesis, antimicrobial, antiquorum-sensing and cytotoxic activities of new series of fused [1,3,4]thiadiazole and [1,3]benzothiazole derivatives

• Published in: Medicinal chemistry research Vol. 23; no. 1; pp. 287 - 299
• Main Authors: El-Gohary, N. S., Shaaban, M. I.
• Format: Journal Article
• Language: English
• Published: New York Springer US 2014
• Subjects: Biochemistry; Biomedical and Life Sciences; Biomedicine; Cell Biology; Original Research; Pharmacology/Toxicology; Pyrimidobenzothiazoles; Thiadiazolopyrimidines; Antimicrobial activity; Thiadiazoloquinazolines; Antiquorum-sensing activity; Cytotoxic activity
• ISSN: 1054-2523; 1554-8120
• DOI: 10.1007/s00044-013-0637-x

New series of [1,3,4]thiadiazolo[3,2- a ]pyrimidines, [1,3,4]thiadiazolo[2,3- b ]quinazolines, and pyrimido[2,1- b ][1,3]benzothiazoles have been synthesized and characterized by analytical and spectrometrical methods (IR, MS, 1 H, and 13 C NMR). Sixteen of the synthesized compounds; namely, 3a , b , 5a – f , 8a , b , 10 , 11a – c , and 13a , b were screened for antibacterial activity against Escherichia coli , Staphylococcus aureus , and Bacillus cereus . They were found to be either moderately active, slightly active or inactive against the selected microorganisms. The antifungal activity of these compounds were also tested against Candida albicans , Aspergillus fumigatus 293, and Aspergillus flavus 3375. Compound 11a showed potent antifungal activity against the three selected fungi; the rest of the tested compounds displayed either weaker activity or were completely inactive. The same compounds were examined for antiquorum-sensing activity against Chromobacterium violaceum ATCC 12472, where compounds 3a , 10 , 11a , and 13a , b exhibited promising activity. The in vitro cytotoxic activity of these compounds was also studied by brine shrimp lethality bioassay, and results indicated that compounds 3a , 11a , and 13a have the highest cytotoxic activity.