Elongation Of Alkyl Chain Research Articles

Alkyl polyglucosides as cell surface modification factors: influence of the alkyl chain length

The use of surfactants in a bioremediation process is aimed at increasing the efficiency of the removal of hydrophobic contaminants from the environment. The subjects of the study were three alkyl polyglucosides (APGs) of different alkyl chain length: Glucopon 215 CS UP, Glucopon 600 CS UP, and Glucopon 650 EC. The impact of these surfactants on the surface properties of the test strain Pseudomonas fluorescens ATCC 14700, as well as on the biodegradation of diesel was tested. It was observed, that the length of alkyl chain has an influence on the cell surface properties. The modification of the cell surface hydrophobicity and the electrokinetic potential on the bacteria cells is dependent on the structure of Glucopon molecules. The elongation of alkyl chains in surfactant molecule caused an increase of the hydrophobic properties and a reduction of the electrokinetic potential on the bacteria cells. Moreover, the use of APGs below critical micelle concentration caused an increase of diesel oil biodegradation, especially in the case of Glucopons with longer alkyl chain (Glucopon 600 CS UP and 650 EC). The better diesel oil removal by tested strain after surfactant addition was correlated with the hydrophobic properties of bacteria strain.

A computational study of dicationic ionic liquids/CO₂ interfaces.

Recent studies on CO2 capture using dicationic ionic liquids (DILs) demonstrated that DILs are promising absorbents for CO2 uptake especially compared with monocationic ionic liquids (MILs) analogues, in which each cation carries single positive charge in contrast to two unit charges of a dication. However, DILs/CO2 interfacial properties at the molecular level are still unknown. This work investigated the CO2 absorption properties of representative DILs, 1-alkyl-3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, [Cn(mim)2](Tf2N)2 (n = 3, 6, 12), using molecular dynamics (MD) simulations. The higher interfacial CO2 density at DIL than that at MIL interfaces suggests the increased CO2 interaction sites in DILs. The interfacial CO2 density also exhibits an alkyl chain length dependence which decreases with the elongation of alkyl chain and proportionally correlates with the content of fluorine atoms at interfaces. Different alkyl chain orientations in DILs were illustrated in contrast to those of MILs; both DILs and CO2 inside DILs exhibit lower diffusivity than MILs, in agreement with the stronger cation-anion binding energy of DILs. Moreover, DILs show a lower H2O and N2 uptake from flue gas compared with MILs, implicating the higher CO2/H2O and CO2/N2 selectivity.

Synthesis of Novel Alkyl-Sulfanyl 1,3,4-Oxadiazolyl-1,3,5,7-Tetraazatricyclic Ammonium Chloride Type Cationic Surfactants

A series of novel cationic surfactants bearing 1,3,4‐oxadiazole and tetraazatricyclic ring structures were synthesized by alkyl chain elongation of 5‐{10‐[4‐(hydroxymethyl)phenoxy]decyl}‐2,3‐dihydro‐1,3,4‐oxadiazole‐2‐thione with homologous series of alkyl bromides, followed by chlorination of the corresponding benzyl alcohols with thionyl chloride and quaternization of the obtained intermediates with hexamethylenetetramine.

Extraction of copper(II) with 1,2-diacylhydrazines in the presence of associated metals

Conditions of Cu(II), Zn(II), Ni(II), Co(II), and Fe(III) ions extraction (pH values, effect of reagent amount) with symmetrical 1,2-diacylhydrazines derived from straight-chain aliphatic carboxylic acids and α-branched higher carboxylic acids Versatic-10 were studied. The separation coefficients of element pairs and pH of half extraction were calculated. The values of [Cu(II)]: [reagent] ratios in extracted complexes were determined. 1,2-Diacylhydrazines were shown to be more selective extractants toward nonferrous metal ions as compared with carboxylic acids, while the branching and elongation of alkyl chain in the reagents enhances their extraction properties and compatibility with hydrocarbon solvents.

Synthesis, antibacterial and antioxidant activities of new 1-alkyl-4-(1-alkyl-4-oxo-1,4-dihydroquinolin-2-yl)pyridinium bromides

New 1-alkyl-4-(1-alkyl-4-oxo-1,4-dihydroquinolin-2-yl)pyridinium bromides (3a–k) were synthesized from 1,4′-diazaflavone [2-pyridin-4-ylquinolin-4(1H)-one] and evaluated for antibacterial and antioxidant activities. A rapid one-pot preparation of 1,4′-diazaflavone (2) was done from 2′-amino substituted chalcone (1) by intramolecular Michael addition using solvent-free microwave heating. New N,N′-dialkyl substituted (C5–C15) 1,4′-diazaflavonium bromides were synthesized from compound 2 with corresponding alkyl halides. Compounds 3a–k were active against six bacteria (MIC: 7.8–500.0 μg/mL). They also showed good antioxidant activities in DPPH scavenging (SC50: 45–133 μg/mL) and ferric reducing/antioxidant power (14–141 μM TEAC) tests. The biological activities decreased as alkyl chain length increased. The reason behind the obvious negative effect of alkyl chain elongation is unclear and requires investigations about the intermolecular interactions of these pyridinium salts with bioassay components.

Temperature Effect on the Monolayer Formation of Substituted Alkanes at the Air/Water Interface: A Quantum Chemical Approach

An approach to calculation of the threshold temperature for spontaneous clusterization of substituted alkanes (amines, nitriles, alcohols, thioalcohols, saturated and unsaturated carboxylic acids, α-amino acids, carboxylic acid amides, and melamine derivatives) at the air/water interface with dependence on the alkyl chain length was developed. In the framework of this approach, four schemes for the description of the temperature dependencies of the thermodynamic parameters of clusterization of the concerned amphiphilic compounds were proposed. They use the data obtained previously in the framework of quantum chemical semiempirical PM3 method and differ from each other by the degree of their theoretical accuracy. It was shown that the threshold temperature for spontaneous clusterization of the regarded classes of substituted alkanes can be described using a fractionally linear function in dependence on the alkyl chain length. It was found that, in agreement with the presented experimental data, the effect of the alkyl chain elongation of the substituted alkanes by two methylene units correlates with the decrease of the subphase temperature (ΔT) by 10-20 K. The general shape of the obtained dependencies indicates that the difference in the ΔT values for the amphiphilic molecules decreases with increasing alkyl chain length. This implies that the contribution of the intermolecular CH···HC interactions between the alkyl chains of monolayer molecules should be a decisive factor.

A simple method for estimation of the 2D cluster formation temperature of substituted alkanes at the air/water interface

A simple method for estimation of the 2D spontaneous clusterization temperature of substituted alkanes at the air/water interface versus alkyl chain length is proposed using the quantum chemical semiempirical PM3 method. The method is approved by long-chain amines, alcohols, thioalcohols, saturated and unsaturated carboxylic acids, α-amino acids and amides of carboxylic acids.The method is based on the experimental fact that short chain amphiphilic molecules cannot form condensed 2D monolayers whereas above a specific alkyl chain length condensed monolayer phases can be observed under the same conditions. That is, elongation of the alkyl chain of amphiphilic molecules causes the increase of intermolecular interaction energy between them what stimulates their close packing and structuring. This leads to linear or stepwise dependencies of enthalpy and entropy of cluster formation on the alkyl chain length. It is possible to obtain an equation for the estimation of the temperature of the spontaneous clusterization threshold of the considered substituted alkane types by setting Gibbs’ energy equal to zero and by knowing the regression expressions for determination of enthalpy and entropy of cluster formation calculated under the condition of 298K using coefficients which determine the contribution of the hydrophilic head group interactions of molecules and CH⋯HC-interactions between the alkyl chains.It is shown that the temperature dependence of the spontaneous clusterization threshold on the alkyl chain length of the amphiphile is fractionally linear with a relative error of 3–8%. The effect of the alkyl chain elongation of substituted alkanes by two methylene units corresponds to subphase temperature reduction (ΔТ) by 10–20K in good agreement with the available experimental data. The difference between ΔТ values for considered types of amphiphilic compounds becomes less significant with the lengthening of the alkyl chain. This indicates the basic contribution of intermolecular CH⋯HC-interactions between the alkyl chains to the process of the 2D clusterization.

2P254 長鎖アルキル基の鎖長延長は環状脂質膜の諸物性に如何に影響を与えるか?(生体膜・人工膜 A) 構造・物性))

2P254 長鎖アルキル基の鎖長延長は環状脂質膜の諸物性に如何に影響を与えるか?(生体膜・人工膜 A) 構造・物性))

Enhancement of antioxidant activity of p-alkylaminophenols by alkyl chain elongation

The initial finding that the p-methylaminophenol ( 6) exhibited antioxidant activity led us to investigate whether the length of alkyl chains linked to the aminophenol residue might affect antioxidative activity. Therefore, we synthesized p-butylaminophenol ( 5), p-hexylaminophenol ( 4), p-octylaminophenol ( 3), and p-methoxybenzylaminophenol ( 7). All p-alkylaminophenols quenched α,α-diphenyl-β-picrylhydrazyl (DPPH) radicals, with 7 being the most potent DPPH radical scavenger. Lipid peroxidation by rat liver microsomes was reduced by p-alkylaminophenols in dose- and aminophenol alkyl chain length-dependent fashion ( 3> 4> 5> 6), with 3 being the most potent lipid peroxidation inhibitor, at approximately 350-fold higher potency than 6. These results indicate that elongation of alkyl chains in p-alkylaminophenols may increase antioxidative activity, and that p-alkylaminophenols may potentially be useful in the development of antioxidants.

Structure-affinity relationship study on N-[4-(4-arylpiperazin-1-yl)butyl]arylcarboxamides as potent and selective dopamine D(3) receptor ligands.

The benzamide PB12 (N-[2-[4-(4-chlorophenyl)piperazin-1-yl]ethyl]-3-methoxybenzamide) (1), already reported as potent and selective dopamine D(4) receptor ligand, has been modified searching for structural features that could lead to D(3) receptor affinity. Changes in the aromatic ring linked to N-1 piperazine ring led to the identification of 2-methoxyphenyl and 2,3-dichlorophenyl derivatives (compounds 6 and 13) displaying moderate D(3) affinity (K(i) = 145 and 31 nM, respectively). Intermediate alkyl chain elongation in compounds 1, 6, and 13 improved binding affinity for the D(3) receptor and decreased the D(4) affinity (compounds 18-26). Among these latter compounds, the N-[4-[4-(2,3-dichlorophenyl)piperazin-1-yl]butyl]-3-methoxybenzamide (19) was further modified with the replacement or of the 2,3-dichlorophenyl moiety (compounds 27-30) or of the 3-methoxyphenyl ring (compounds 31-41). In this way, we identified several high-affinity D(3) ligands (0.13 nM < K(i)'s < 4.97 nM) endowed with high selectivity over D(2), D(4), 5-HT(1A), and alpha(1) receptors. In addition, N-[4-[4-(2,3-dimethylphenyl)piperazin-1-yl]butyl]-3-methoxybenzamide (27) and N-[4-[4-(2,3-dichlorophenyl)piperazin-1-yl]butyl]-7-methoxy-2-benzofurancarboxamide (41) appear to be valuable candidates for positron emission tomography (PET) because of their affinity values, lipophilicity properties, and liability of (11)C labeling in the O-methyl position.

Structure-Activity Relationships of Alkylxanthines: Alkyl Chain Elongation at the N1- or N7-Position Decreases Cardiotonic Activity in the Isolated Guinea Pig Heart

Relationships between the alkyl substitutions (C1–C6) and cardiac inotropic activities of xanthine derivatives were studied in isolated guinea pig heart muscles. Most of the alkylxanthines exhibited positive inotropic activity on the left atrium, which was increased with an elongation of alkyl chain at the N3-position but decreased by substitution of a long alkyl group at the N1- or N7-position of the xanthine skeleton. Although positive inotropic activity in the right ventricular papillary muscle was also increased by longer alkyl groups at the N3-position, the inotropic activity became negative with an increment in alkyl chain length at the N1- or N7-position. The positive inotropic activity of alkylxanthines was correlated with their inhibitory activity on the phosphodiesterase (PDE) III isoenzyme. Adenosine Ai antagonism and PDE IV inhibitory activity were also partly associated with the inotropic activity because H-89, an inhibitor of cyclic AMP-dependent protein kinase, diminished the positive inotropic action and potentiated the negative inotropic action. These results indicate that the positive inotropic activity of alkylxanthines becomes weak with elongation of alkyl chains at the N1- and N7-positions; In particular, xanthines having two long alkyl chains show a negative inotropic activity on the right ventricular papillary muscle, an effect that could not be elucidated from their cyclic AMP-dependent action.