Original Articles: 2015 Vol: 7 Issue: 7
Synthesis of some benzothiazole derivatives evaluated as antimicrobials and antibiofilms
Several new benzothiazole hybrids with other heterocyclic structures were synthesized in an attempt for exploring a new class of antibacterial, antifungal and antibiofilm agents. These derivatives include 2-(5-cyano-1,6-dihydro-6-oxo-4-arylpyrimidin-2-ylthio)-N-(6-substituted benzo [d] thiazol-2-yl)acetamide 4a-n, 2-imino-3-(6-substituted benzo[d]thiazol-2-yl)-5-(4-(un) substituted arylidenyl)thiazolidin-4-one 6a-n and 3-(6-Substitutedbenzo[d]thiazol-2-yl)-2-((N,N-disubstituted amino methyl)imino) thiazolidin-4-one 7a-f. The target compounds were synthesized starting from 6-substitutedbenzo[d]thiazol-2-amine 1a, 1b and their structures were elucidated on the basis of elemental analyses and spectral data. These compounds were screened for their antibacterial activity against gram-positive bacteria (B. subtilis, S. lutea and S. aureus), gram-negative bacteria (E. coli ATCC 25922, E. coli ATCC 5087, P. aeruginosa and P. vulgaris) and antifungal activity against C. albicans through the sensitivity test using cup plate method. Minimum inhibitory concentration was measured for the only active compounds using agar dilution method. It was shown that the two classes incorporating the 2-imino-thiazolidin-4-one structure showed more antibacterial and antifungal activities and more pronounced MIC values than the class incorporating the dihydropyrimidinone. Additionally, the antibiofilm activity of the most active compounds 6a, 6b, 6h, 6i, 6k, 6l, 7c, 7d, 7e and 7f as antifungals comparing to fluconazole were screened against 2 pathogenic Candida isolates CA1 and CA2 using the fluconazole as the model system. Biofilm growth was monitored semiquantitatively by colorimetric assay using the crystal violet as indicator.