- Synthesis, surface adsorption, micellization behavior and antibacterial activity of novel gemini surfactants with morpholinium headgroup and benzene-based spacer
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Two series of novel gemini surfactants with morpholinium headgroup and benzene-based rigid spacers (abbreviated as (Mor)m-P-m and (Mor)m-BP-m, where m represents the carbon numbers of hydrophobic chains) were synthesized and characterized by 1H NMR, ESI-MS, and FT-IR spectra. The effect of lengths of rigid spacer and hydrocarbon chain on their solution properties and antibacterial activities were systematically investigated. Due to the existence of morpholinium, they have a superior surface activity to the classic gemini surfactants. (Mor)m-BP-m possess lower CMC and γcmc than (Mor)m-P-m, which is assumed to be related to the conformation change of spacer. The possible arrangement models for the adsorptions of (Mor)m-P-m and (Mor)m-BP-m at the air-water interface were proposed by comparing their surface parameters with those of other similar surfactants. The pre-micellar associations occur in aqueous solutions of (Mor)16-P-16, (Mor)14-BP-14 and (Mor)16-BP-16. The thermodynamic parameters indicate the micellar processes are spontaneous, and (Mor)m-BP-m have stronger aggregation tendency than (Mor)m-P-m. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) show they spontaneously self-assemble into vesicle, and the aggregate size of (Mor)m-BP-m is larger than (Mor)m-P-m. These surfactants showed excellent antibacterial properties against Bacillus subtilis and Escherichia coli. Compared with (Mor)m-P-m, (Mor)m-BP-m exhibit a higher activity.
- Zheng, Le-Chi,Tong, Qing-Xiao
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- Vinyl Sulfonates: A Click Function for Coupling-and-Decoupling Chemistry and their Applications
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The term coupling-and-decoupling (CAD) chemistry refers to applications in which efficient bond formation and subsequent cleavage between two moieties is required. Within this context, the scope of the vinyl sulfonate (VSO) group as an efficient tool for CAD chemistry is reported. The coupling step relies on the click features of the Michael-type addition of diverse nucleophiles to vinyl sulfonates as a valuable methodology. The feasibility of this strategy has been proved by the high yields obtained in mild conditions with model VSO derivatives. Cleavage of the resulting sulfonate adducts either through nucleophilic substitution with different nucleophiles (for alkyl VSO groups) or through hydrolysis (for both alkyl and aryl VSO) are successful strategies for the decoupling step, the former being the most promising, as the reaction proceeds under milder conditions with thiol nucleophiles. Moreover, the click VSO coupling chemistry proves to be orthogonal with the click CuAAC reaction, which enables the VSO-CAD methodology for the preparation of hetero-bifunctional clickable and cleavable linkers for double click modular strategies. The potential of the VSO-CAD chemistry is demonstrated in two biologically relevant examples: the decoupling of sulfonates with glutathione (GSH) under conditions compatible with those of living systems; and the synthesis of homo- and heterogeneous multivalent glycosylated systems from 1-thio and 1-azido or 1-azidoethyl sugar derivatives and bis-vinyl sulfonates (homo systems) or alkynyl-VSO bifunctional clickable-cleavable linkers (hetero systems). As proof of concept, the cleavable character of these multivalent systems was demonstrated by using one of them as a reversible linker for the non-covalent assembling and chemical decoupling of two model lectins. (Figure presented.).
- Cruz, Carlos M.,Ortega-Mu?oz, Mariano,López-Jaramillo, F. Javier,Hernández-Mateo, Fernando,Blanco, Victor,Santoyo-González, Francisco
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p. 3394 - 3413
(2016/11/13)
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- Nematocidal activity of long alkyl chain amides, amines and their derivatives on dog roundworm larvae
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The nematocidal activity of amides and amines having a long alkyl chain against the second-stage larva of dog roundworm, Toxocara canis, was examined. Long chain acyl amides with smaller substituents on the nitrogen showed stronger activity and the activity of cyclic amine amides was stronger than that of acyclic ones. In a series of homologous amides, the activity was dependent on the alkyl chain length: it reached a maximum at an optimal chain length and decreased in both shorter and longer homologues. The relationship between the activity and hydrophobicity of the homologues was analysed by the use of the bilinear model. The hydrophobicity of a compound, which gives a maximal activity, was similar for all neutral amides, but amides which have an additional amine group in the molecule had different values. Tertiary amines and their salts having a long alkyl chain also showed nematocidal activities comparable to those of the corresponding amides. The salts killed the larva at concentrations lower than their critical micell concentration, suggesting that they behave as a single molecule for the nematocidal action.
- Kiuchi,Nishizawa,Kawanishi,Kinoshita,Ohsima,Uchitani,Sekino,Ishida,Kondo,Tsuda
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p. 3234 - 3244
(2007/10/02)
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