Carbon Atoms In Aliphatic Chain Research Articles

Retention behavior of a homologous series and positional isomers of aliphatic amino acids in hydrophilic interaction chromatography

The retention behavior of several series of free α- and ω-amino acids and positional isomers of amino pentanoic acid in the hydrophilic interaction chromatography mode (HILIC) was studied. The study was carried out on three stationary phases followed by post-column derivatization with fluorescence detection in order to describe the retention mechanism of the tested amino acids. The effect of chromatographic conditions including acetonitrile content in the mobile phase, mobile phase pH (ranging from 3.5 to 6.5) and concentration of buffer in the mobile phase was investigated. The effect of the number of carbon atoms (nC) in aliphatic chains of the individual homologue of α- and ω-amino acids and the logarithm of the partition coefficient (logD) on retention was also a part of the presented study. A good correlation (r > 0.98) between the logk and logD values of amino acids or nC, respectively, was observed. The described linear relationships were subsequently applied to predict the retention behavior of individual members of the homologous series of amino acids and to optimize the mobile phase composition in HILIC. The obtained results confirmed that the retention mechanism of α-amino acids, ω-amino acids and positional isomers of amino acids was based on the logD values and the number of carbon atoms in the aliphatic chains of amino acids. The elution order of ω-amino acids and positional isomers of amino pentanoic acid was strongly dependent on the mobile phase pH in the investigated range whereas the retention factors of all α-amino acids remained essentially unchanged on all tested stationary phases.

New cyclopentaquinoline derivatives with fluorobenzoic acid induce G1 arrest and apoptosis in human lung adenocarcinoma cells

Non-small cell lung cancer accounts for 80–85% of all lung cancer cases and is the leading cause of cancer death indicating inefficient current treatment. Acridine derivatives interact with DNA and inhibit topoisomerase leading to cell growth arrest or cell death. The aim of this study was to evaluate the effects of new synthesized sixteen 2,3-dihydro-1H-cyclopenta[b]quinoline derivatives (cyclopentaquinoline), a member of acridine-based compounds, on the survival and growth of human lung adenocarcinoma, A549 cells. Anticancer activity of eight new cyclopentaquinoline derivatives with hydrazinonicotinic acid (compounds 1–8) and eight with fluorobenzoic acid (compounds 9–16) were screened using WST-1 assay. Interestingly, cyclopentaquinoline derivatives with fluorobenzoic moiety were found to have a higher anticancer activity than derivatives with hydrazinonicotinic acid. Four out of eight tested compounds with fluorobenzoic acid inhibited 50% cancer cell growth at concentration below 20μM. Moreover, the efficacy of cyclopentaquinoline derivatives containing fluorobenzoic acid correlated with increasing number of carbon atoms in the aliphatic chain. The most effective compounds (6, 15, 16) were selected to determine molecular mechanisms of their anticancer action. The results indicated that inhibition of A549 cell growth by compounds 15 and 16 was associated with a cell cycle arrest at G0/1 phase and with induction of caspase 3-dependent apoptosis. Compound 6 also caused A549 cells death due to apoptosis, however, it had no significant effect on a cell cycle progression. These findings suggest that cyclopentaquinoline derivatives containing fluorobenzoic acid with 8 and 9 carbon atoms in aliphatic chain may be promising candidate for treatment of lung cancer.

Structure of cadmium and lead sulfide nanoclusters in a matrix of a langmuir-blodgett film

Semiconducting materials in the form of nanoclusters distributed in an organic or silicate matrix are of interest to researchers engaged in the field of nanoelectronics and nonlinear optics. These materials involve cadmium, zinc, lead, and mercury chalcogenides in silicate glass or Langmuir-Blodgett (LB) films of fatty acids [1-3]. Investigations in the field of chemical modification of multimolecular LB layers are of great importance for the design of organized molecular assemblies as new nonclassical objects in the physics of low-dimensional systems as well as functional molecular electronics and sensor technology [4]. Formation of lead, zinc, and cadmium sulfides as nanosized clusters by reactions of the corresponding metal behenate films with gaseous hydrogen sulfide was established in [5], where sulfidizing of behenate films was studied at different temperatures and pressures of hydrogen sulfide. In this work we study the structure of the sulfides. Formation of nanoclusters was established, and their size and concentration in the film were determined. Experimental procedure. Cadmium and lead behenate fdms were prepared by the Langmuir-Blodgett procedure. To create monolayers on the surface of a liquid we used hexane solutions of behenic acid and cadmium chloride and lead acetate solutions as a subphase with a concentration of 3-5-10 -4 M, pH 7.0. The monolayers were transferred at a surface pressure of 30-35 mN/m and temperature 22-23~ Conditions of film sulfidizing: H2S pressure 50-100 Torr, temperature 20-5C the holes were subsequently covered with a LB film. These were just the regions investigated by HREM. To obtain an electron diffraction pattern in the reflection mode, the films were applied to polished silicon single crystal plates. Cadmium and lead behenate films of 20 to 30 monolayers (corresponding to a film thickness from 60 to 90 nm) were studied prior to and after sulfidizing. Completeness of sulfidizing was monitored by IR spectra. Experimental results. According to electron diffractometry, cadmium behenate films are characterized by a distinct plate-like texture (Fig. 1). The lattice is hexagonal and has a c axis that is close, on the average, to the normal to the support. Scanning the film showed a 10 ~ change in the inclination of the c axis. The parameters of the hexagonal lattice of the crystal as determined from electron diffractograms are a = 4.8 ~ and c = n 7.5 ~, where n is an integer. Recording by the skewed texture method revealed periodic intervals of 2.2-2.5 A along the c axis, which may be due to periodicity of the arrangement of carbon atoms in aliphatic chains. The crystal structure of lead behenate is analogous

Crystal and molecular structure of the monobino dicyclophosphazene N 3P 3Cl 5 [HN(CH 2) 30(CH 2) 6 O(CH 2) 3NH] Cl 5P 3N 3

Reaction of N 3P 3Cl 6 with 4,11-dioxatetradecane-1,14-diamine (coded as 30603) in THF leads stereospecifically to the mono-BINO (30603) derivative in which one [HN(CH 2) 3O(CH 2) 6 0(CH 2) 3NH] ligand bridges two N 3P 3Cl 5 moieties. This compound crystallizes in the mono- clinic system, P2 1/ c, a= 11.788(2), b= 16.660(6), c=9.241 (3) Å,β= 110.81(2)°, V=1696(2) Å 3, G9 x = 1.66(2) Mg m −3, R=0.059 for 1823 unique reflections and 179 variable parameters. The [HN (CH 2) 3O(CH 2) 6O&2sbnd;(CH 2) 3NH] ligand appears quite unfolded with twelve atoms strictly co- planar. The two N 3P 3Cl 5 moieties are trans to this plane with a double scorpion sting-like confor- mation at the edgings of the bridge. (CC) bond lengths and (CCC) bond angles in the ligand are 1.514(1) Å and 111.2(8)°, respectively, which is very close to refined parameters recently proposed by Allinger (1.5247 Å, 111.0°) in their molecular mechanics force field MM3. Thus, the van't Hoff model (1.54 Å, 109.5°) which is correct for pure T d structures of methane and neopentane, is no longer suitable for the description of C 2v carbon atoms in aliphatic chains.