Bis-imidazolium and benzimidazolium based gemini-type ionic liquids structure: synthesis and antibacterial evaluation

Abstract

Based on bis-imidazolium and benzimidazolium, new sets of geminal dicationic ionic liquids containing sulphonamide moiety were successfully synthesized with good yields. Their structures were confirmed by 1 H-NMR, 13 C-NMR, FT-IR, and mass spectroscopy. Selected physicochemical properties of these ILs including; thermal stability by TGA and miscibility in some common organic solvents and water were also determined. Most of the prepared dicationic ILs displayed significant level of antibacterial activities against ten selected bacterial strains of Gram-positive and Gram-negative using micro-broth dilution assay. ͞ calcd. for C 29 H 42 N 5 O 6 S 3+ : 588.2856, found: 588.2919; m/z, [NTF 2 ] ͞ calcd. for C 2 F 6 NO 4 S 2 − : 279.9173, found: 279.9145. N,N-bis[(3-allyl-benzimidazol-1-iumyl)ethyl]-4-methylbenzenesulphonamide-bis(trifluorometh- ylsulphonyl)amide (8a)This compound was prepared analogously to 7d using N, N-bis[(3-allyl-benzimidazol-1-iumyl) ethyl]-4-methylbenzenesulphonamide bromide 6a (0.7 g, 1.0 mmole) and Lithium bis-(trifluoromethanesulphonyl)imide LiNTf 2 (0.72 g, 2.5 mmol) to provide a clear viscous hygroscopic liquid at room temperature in 90% yield (1 g). Ten standard strains of Gram positive and negative bacteria were used to evaluate the antibacterial activities of the synthesized ILs compounds; 5a-f and 6a-f. Based on CLSI guidelines 85 , the activities were assessed in terms of minimum inhibitory concentrations (MICs) using microbroth dilution assays. The MIC's values are given in mg/mL and defined as a lowest concentration that inhibits the bacterial strains growth. Gram positive bacteria included: Streptococcus pyogenes ATCC19615, Staphylococcus aureus ATCC 29213, Bacillus subtilis ATCC6051, Rodococcus Ruber ATCC27863, Enterococcus faecalis ATCC 29212, Staphylococcus epidermidis ATCC12228, while Gram negative bacteria included: Escherichia coli ATCC10538, Salmonella typhimurium ATCC14028, Pseudomonas aeruginosa ATCC15442, Acinetobacter calcoaceticus ATCC 23055. These standards strains were obtained from the collection Distilled water was used as negative control to dissolve all the tested ILs in concentrations range of 0.05-0.5 mg/mL, while, commercial antibiotics amoxicillin and kanamycin were used as a positive control in the same range of concentrations. A loopful of bacterial cells from the nutrient agar plates ofThe incorporated benzenesulfonamide moiety and the active side substituents into diimidazolium and benzimidazolium cations enhanced both antibacterial activity and miscibility for the synthesized gimini type ILs.

Synthesis of Imidazolium Oligomers with Planar and Stereo Cores and Their Antimicrobial Applications

“…All planar and stereo compounds werefound to exhibit antimicrobial activity against the tested microbes. [11] and another series of di-imidazolium salts reported by Al-Mohammed et al [12] are about 25-50 mgmL À1 , which are highert han the MIC values for A 2 PC 1-3 .T his implies that the planaro ligomers are more activet han di-imidazolium salts. [14,18] The MIC values against E. coli for [p-C 8 im]-basedd i-imidazolium salts reported by Cancemie tal.…”

“…[14,18] The MIC values against E. coli for [p-C 8 im]-basedd i-imidazolium salts reported by Cancemie tal. [11] and another series of di-imidazolium salts reported by Al-Mohammed et al [12] are about 25-50 mgmL À1 , which are highert han the MIC values for A 2 PC 1-3 .T his implies that the planaro ligomers are more activet han di-imidazolium salts. The MIC values of A 3 PC 1 and A 3 PC 3 against P. aeruginosa are lower than those of A 2 PC 1 and A 2 PC 2 ,r espectively.T he ortho-xylylene linker is probably more suitable for the formation of amphiphilic topography,w hich facilitates binding of the polymers to the lipid membrane, leading to membrane rupture and eventually cell death.…”

“…[9] Dimeric imidazolium compounds have shown high antimicrobial activity and low toxicity toward mammalian cells. [10][11][12] There are relatively few studies on imidazolium oligomers with five to fifteen imidazolium units in their chain structures. [13] In fact, imidazolium oligomers have potentialf or various applications, as they have defined molecular weights and versatile molecular structures.…”

Synthesis and Antibacterial Evaluation of Bis‐thiazolium, Bis‐imidazolium, and Bis‐triazolium Derivatives

“…[7,8] Furthermore, one general drawback of this class of compounds comesf rom the low selectivity toward eukaryotic cells. Some bis-imidazolium compounds were already preparedb yo thers [15,16] and showed interesting, yet moderate, antibacterial activity.W ee nvisioned replacing somea lkyl moietiesw ith aromatic groupst od etermine their influence on both antibacterial activity and toxicity versuse ukaryotic cells. [9,10] In addition, other recente fforts led to the designo fp owerful molecules that show very low toxicity toward mammalian cells.…”

“…Moreover,w ei ntended to extend this study to relatedf ive-membered heterocycles such as imidazole derivatives. Some bis-imidazolium compounds were already preparedb yo thers [15,16] and showed interesting, yet moderate, antibacterial activity.W ee nvisioned replacing somea lkyl moietiesw ith aromatic groupst od etermine their influence on both antibacterial activity and toxicity versuse ukaryotic cells. Finally,1 ,2,4-triazole analogues were also prepared, as in the context of antifungal therapy,t hey have led to more active compounds, [17] andi nterestinga ntibacteriala ctivities have recently been reported.…”