Synthesis, Surface-Active Properties, and Antimicrobial Activities of New Double-Chain Gemini Surfactants

Abstract

A novel series of neutral and cationic dimeric surfactants were prepared involving ketalization reaction, Williamson etherification, and regioselective oxirane ring opening with primary and tertiary alkyl amines. The critical micelle concentration (CMC), effectiveness of surface tension reduction (g CMC ), surface excess concentration (G), and area per molecule at the interface (A) were determined and values indicate that the cationic series is characterized by good surface-active and self-aggregation properties. For the first time, we reported the antimicrobial activities against representative bacteria and fungi for dimeric compounds. The antimicrobial activity was found to be dependent on the target microorganism (Grampositive bacteria > fungi > Gram-negative bacteria), as well as both the neutral or ionic nature (cationic > neutral) and alkyl chain length (di-C 12 > di-C 18 > di-C 8 ) of the compounds. The cationic di-C 12 derivative was found to have equipotent activity to that of benzalkonium chloride (BAC) used as standard. Murguía, V.A. Vaillard, V.G. Sánchez et al. method, surface-active properties, and the antimicrobial activity of neutral and cationic series of new gemini compounds having a flexible, hydrophilic spacer and two alkyl chains of varying length. The molecular design and synthetic strategy were outlined to link the two hydrophilic head groups through a spacer having multiple oxygen atoms (1,3-dioxane ring, ether, and hydroxyl groups) conferring wettable properties. The structures of the synthesized compounds are illustrated in . EXPERIMENTAL PROCEDURES 1All the chemicals used in synthetic procedures were of reagent grade quality and used as received. 21 5 5 5 3 3 2 The reaction was carried out in a 100 mL three-neck round-bottomed flask equipped with a magnetic stirring bar and a Dean-Stark trap topped with a condenser 24,25) . A catalytic amount of p-toluenesulfonic acid monohydrate (5% w/w relative to the cyclohexanone) was added to a pentaerythritol (2.995 g, 22 mmol) and benzene-dimethylformamide (40 : 60) mixture (50 mL) at room temperature. The well-stirred dispersion was warmed to 80 until complete dissolution, and cyclohexanone (1.571 g, 15 mmol) was then added dropwise while the reaction mixture was heated to 115 for 48 hours. The water formed during the reaction was removed by distillation and collected in the Dean-Stark trap. The reaction was stopped when there was no further increase in the collected water. After cooling, the reaction mixture was poured into water (30 mL), neutralized with potassium carbonate and three-fold extracted with dichloromethane (30 mL). The organic layer was dried with MgSO 4 and evaporated in vacuo. After Kugelrohr distillation and column chromatography on silica gel by eluting with ether-light petroleum (80 : 20) mixture, the compound was obtained as a white solid in good yield (90 %) and good selectivity (92 %). (13), 173 (96), 160 (4), 125 (5), 101 (6), 99 (14), 83 (34), 71 (40), 55 (100), 41 (72) 26,27) . A 1 : 10 : 6 : 0.1 molar ...

Synthesis of New Sulfobetaine Gemini Surfactants with Hydroxyls and Their Effects on Surface‐Active Properties

“…This behavior is related to the difficulties in organizing sulfobetaine gemini surfactants at the air/water interface. The surface tension was then measured three times for each sample within 40 min interval between each reading to ensure equilibrium data (Murguía et al, ). The CMC was determined using a series of aqueous solutions at various concentrations and estimated from the break point of each surface tension versus concentration (on log scale) curves in Fig .…”

Antimicrobial Activity of Cationic Gemini Surfactant Containing an Oxycarbonyl Group in the Lipophilic Portion against Gram-positive and Gram-negative Microorganisms

“…As discussed in the work of Murguía et al, the MIC values of II-12-2 t-butene for Gram-positive microorganisms were expected to be lower than for Gram-negative microorganisms, because the outer membrane of Gramnegative microorganisms is thought to be less permeable to surfactants than that of Gram-positive microorganisms 18 .…”

Bactericidal and virucidal ultrathin films assembled layer by layer from polycationic N-alkylated polyethylenimines and polyanions

“…3B). The difference in the composition of the cell walls of these two types of bacteria should influence the way that positive charges coupled with hydrophobic alkyl chains interact with them [46]. Gram positive bacteria have a simple cell wall consisting of a thick peptidoglycan layer, while Gram negative bacteria have cell walls made out of a lipopolysaccharide layer, a thin peptidoglycan layer, and the periplasmic space [47].…”