New Shciff Bases from 6, 6′-dimethyl-2, 2′-bipyridyl. synthesis, characterization, antibacterial and anticancer studies
Eight novel Schiff Bases, from 6, 6?-diformyl-2, 2?-bipyridyl (1a, 43%) with O, N, S and F containing amines: Thiosemicarbazide (2a, 70%), 4-Ethyl-3-thiosemicabazide (2b, 75%), 4, 4-Dimethyl-3-thiosemicarbazide (2c, 75%), S-benzyldithiocarbazide, SBDTC (2d, 80%), (Trifluromethyl) phenylhydrazine (2e, 80%), 4-Phenyl-3-thiosemcarbazide (2f, 80%), Thiocarbazide (2g, 70%), 2-Aminothiophenol (2h, 65%), have been synthesized. The conventional method of synthesis of the Schiff bases involves refluxing the reaction mixture containing the diformyl and amines for 1 hour. The solid products that had formed filtered off using suction filtration. In few reactions, 2 - 3 drops of conc. sulfuric acid used to obtain high yield. The structures of all eight novel synthesized compounds have fully been characterized by spectroscopic (IR, NMR, MS) data. These eight novel Schiff bases, one intermediates along with seventeen compounds from our external collaborator (University of Brunei Darussalam) used for antibacterial study. Disc diffusion technique used to carry out bacterial screening tests of the synthesized compounds. In order to determine the minimum inhibitory concentrations (MIC) of these compounds, least concentration 100?g/mL used for tube dilution method. Due to lack of reagents, further studies could not carry out to find the MIC (except few) for each of the compounds that showed activities higher than standard tetracycline. All the compounds showed antibacterial activity at the tested dose against seven humans and eighteen plant pathogenic bacteria: both gram positive and gram-negative strain. However, activity of a number of compounds was considerably less when compared to the reference standard drug tetracycline. But, compounds IJ-16, IJ-19, IZ-4, Zm-15 and Zm-13 showed very high activity against some human pathogenic bacteria and compounds Zm-15, IZ-4, 2a, 2b, 2d, 2f, HS-5, HS-4 and 2g showed activity against plant pathogenic bacteria, even much higher active than standard tetracycline. Growth analysis of cancer cell line A549 after 24-hour exposure to compound 2h showed significant inhibition. Compounds 2a, 2b and 2g did not show any significant inhibition against cancer cell line A549. In all case, calculated probability (p<0.005) was obtained using two way Anova.
"New Shciff Bases from 6, 6′-dimethyl-2, 2′-bipyridyl. synthesis, characterization, antibacterial and anticancer studies"
ETD Collection for Tennessee State University.