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Synthesis of methyl 12-benzoyldehydroabietate
in ionic liquid
XU Xuetang, DUAN Wengui, HUANG Mei, PENG Qinghua, LIU Xiongmin
Front. Chem. China. 2008, 3 (4): 363-369.
https://doi.org/10.1007/s11458-008-0086-0
In the presence of the ionic liquid [bmim]Br/AlCl3 as green reaction medium, methyl 12-benzoyldehydroabietate was synthesized through Friedel-Crafts acylation reactions on the aromatic ring of methyl dehydroabietate. The optimum synthetic conditions of the target product were found to be as follows: molar ratio of methyl dehydroabietate to [bmim]Br to AlCl3 to benzoyl chloride 1:4:8:8, reaction temperature 40°C, reaction time 2 h. The target product was analyzed and characterized by means of IR, MS, NMR and elemental analysis. The results show that this novel method has the advantages of mild condition, short reaction time and environmental benignity.
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Preparation of bovine hemoglobin-imprinted
polymer beads the photografting
surface-modified method
LIU Qiuye, LI Wenyou, HE Xiwen, CHEN Langxing, ZHANG Yukui, GAI Qingqing, GAI Qingqing
Front. Chem. China. 2008, 3 (4): 370-377.
https://doi.org/10.1007/s11458-008-0089-x
Molecularly imprinted polymers (MIPs), based on photografting surface-modified polystyrene beads as matrices, were prepared with acrylamide as the functional monomer, bovine hemoglobin as the template molecule and N, N′-methylene bisacrylamide as the crosslinker in a phosphate buffer. The results of IR, scanning electron microscope (SEM) and elemental analyses demonstrated the formation of a grafting polymer layer on the polystyrene-bead surface. Subsequent removal of the template left behind cavities on the surface of the polymer matrix with a shape and an arrangement of functional groups having complementary binding sites with the original template molecule. The adsorption studies showed that the imprinted polymers have a good adsorption capacity and specific recognition for bovine hemoglobin as the template molecule. Our results demonstrated that the polymer prepared via the photografting surface-modified method exhibited better selectivity for the template. Attempts to employ the new method in molecular imprinting techniques may introduce new applications for MIPs and facilitate probable protein separation and purification.
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Synthesis and characterization of molecularly
imprinted polymers for recognition of ciprofloxacin
LIU Pengyan, LIU Lei, ZHANG Li, JIANG Ning, LIU Zhanli, WANG Yun
Front. Chem. China. 2008, 3 (4): 378-383.
https://doi.org/10.1007/s11458-008-0085-1
A molecularly imprinted polymer (MIP), with special molecule recognition properties of ciprofloxacin (CIP), was prepared by thermal polymerization in which ciprofloxacin acted as template molecule, ?-methacrylic acid (MAA) acted as functional monomer and trimethylolpropane trimethylacrylate (TRIM) acted as crosslinker. The optimized ratio was determined to be n(CIP): n(MMA):n(TRIM) = 1:6:16 by investigation of the effects of different concentrations of functional monomer and the crosslinker on the MIP’s recognition properties. Equilibrium binding experiment was used to investigate the adsorption dynamics, the binding ability to template molecule and the substrate selectivity. Scatchard analysis was used to study the MIP’s binding characteristic to template molecule. The results indicated that MIP has higher adsorption ability and selectivity. The equilibrium distribution coefficient KD was 41.64 and the separation factor ? was 1.62. Scatchard analysis showed that two different kinds of binding sites were produced in the polymer matrix and their dissociation constants were calculated to be Kd1 = 5.249 × 10-5 mol·L-1, Kd2 = 2.237 × 10-3 mol·L-1.
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Design of parallel microfluidic gradient-generating
networks for studying cellular response to chemical stimuli
WANG Lihui, WANG Bo, SUN Jie, LI Lianhong, LIU Dayu
Front. Chem. China. 2008, 3 (4): 384-390.
https://doi.org/10.1007/s11458-008-0087-z
A microfluidic chip featuring laminar flow-based parallel gradient-generating networks was designed and fabricated. The microchip contains 5 gradient generators and 30 cell chambers where the resulting concentration gradients of drugs are delivered to stimulate on-chip cultured cells. The microfluidics exploits the advantage of lab-on-a-chip technology by integrating the generation of drug concentration gradients and a series of cell operations including seeding, culture, stimulation and staining into a chip. The microfluidic network was patterned on a glass wafer, which was further bonded to a PDMS film. A series of weir structures were fabricated on the cell culture reservoir to facilitate cell positioning and seeding. Cell injection and fluid delivery were controlled by a syringe pump. Steady parallel concentration gradients were generated by flowing two fluids in each network. Over time observation shows that the microchip was suitable for cell seeding and culture. The microchip described above was applied in studying the role of reduced glutathione (GSH) in mediating chemotherapy sensitivity of MCF-7 cells. MCF-7 cells were treated with concentration gradients of As2O3 and N-acetyl cysteine (NAC) for GSH modulation, followed by exposure to adriamycin. GSH levels were down-regulated upon As2O3 treatment and up-regulated upon NAC treatment. Suppression of intracellular GSH by treatment with As2O3 has been shown to increase sensitivity to adriamycin. Conversely, elevation of intracellular GSH by treatment with NAC leads to increased drug resistance. The integrated microfluidic chip is able to perform multiparametric pharmacological profiling with easy operation, and thus holds great potential for extrapolation to the cell based high-content drug screening.
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Interaction of water-soluble bridged porphyrin
with DNA
WANG Kai, ZHANG Zhi, GUO Qianni, BAO Xiaoping, LI Zaoying
Front. Chem. China. 2008, 3 (4): 406-412.
https://doi.org/10.1007/s11458-008-0073-5
A water-soluble porphyrin dimer (Por Dimer) containing eight positive charges, bridged by 4,4′-dicarboxy-2,2′-bipyridine, has been synthesized. With Meso-tetrakis(N-methyl-pyridium-4-yl)porphyrin (H2TMPyP) as the reference compound, the water-soluble porphyrin dimer was investigated for its interaction with DNA by absorption, fluorescence, and circular dichroism (CD) spectroscopy. The apparent affinity binding constant (Kapp = 1.2 × 106) of Por Dimer binding to CT DNA was measured by a competition method with ethidium bromide (EB) (that of H2TMPyP was 6.9 × 106). The cleavage ability of Por Dimer to pBR322 plasmid DNA was studied by gel electrophoresis. The results suggest that the binding modes of Por Dimer were complex and involve both intercalation and outside binding.
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Synthesis and catalytic properties of tetraorganodistannoxanes
containing silicon
HE Xiaoli, LU Lude, WANG Xin, YANG Xujie, HE Xiaoli, GUO Xuan
Front. Chem. China. 2008, 3 (4): 413-417.
https://doi.org/10.1007/s11458-008-0074-4
Three tetraorganodistannoxanes containing silicon were synthesized and their catalytic properties in esterification and acetalization were observed via the reactions of acetic acid with isoamyl alcohol and butyraldehyde with glycol. The factors affecting the reaction, such as the catalyst dosage, reaction time and solvent, etc. were discussed. The results show that the three tetraorganodistannoxanes displayed similar good catalytic activities compared to dichlorotetrabutyldistannoxane in esterification and acetalization. When the dosage of [ClBu2SnOSn-(CH2SiMe3)2Cl]2 was 1.5% based on the mass of reactant, the yield of isoamyl acetate was 91.8% and the yield of butyraldehyde glycol acetal 94.2%. The different alkyl and bridging groups on Sn sites in the structure of tetraorganodistannoxanes showed some influence on the catalytic activities of these compounds.
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Synthesis and fungicidal activity of novel 3,5-diarylpyrazole
derivatives
LIU Xinhua, ZHU Jing, PAN Chunxiu, LI Bo, SONG Bao‘an
Front. Chem. China. 2008, 3 (4): 418-421.
https://doi.org/10.1007/s11458-008-0075-3
(E)-3-(2-chlorophenyl)-1-(2,4-dichlorophenyl)prop-2-en-1-one was prepared from 2-chlorobenzaldehyde followed by cyclization with hydrazine monohydrate. Eight new 3-(2,4-Di-chlorophenyl)-5-(2-chlorophenyl)-4,5- dihydro-N-acylpyrazole derivatives were synthesized and characterized by elemental analysis, IR and 1H NMR spectroscopy. The experimental results show that the inhibition ratio of compounds 3f towards H. Oryzae and P. oryzae at 50 mg·L-1 is 55.2% and 57.1%, respectively. The inhibition ratio of compounds 3g towards H. Oryzae, P. oryza, S. Sclerotiorum at 50 mg·L-1 is 53.3%, 60.0%, 50.4% respectively.
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Modification effects of amphiphilic comb-like
polysiloxane containing polyether side chains on the PVDF membranes
prepared phase inversion process
QIAN Yanling, WANG Jianhua, ZHU Baoku, ZHANG Mei, DU Chunhui, XU Youyi
Front. Chem. China. 2008, 3 (4): 432-439.
https://doi.org/10.1007/s11458-008-0078-0
Amphiphilic comb-like polysiloxane (ACPS) containing polyether side chains was used as the modification reagent in the preparation of hydrophilic porous poly(vinylidene fluoride) (PVDF) membranes via a phase inversion process. The effects of ACPS on morphology, crystallinity, mechanical properties, reservation of ACPS in the phase inversion process, chemical structure, hydrophilicity and filterability performance of porous PVDF membranes were discussed. It was found that the addition of ACPS would result in the delayed demixing which yields “sponge-like” sublayers and longer crystallization time during the membrane formation process. It was revealed that O/F ratios of the bulk membrane were almost the same as those of the corresponding casting solutions which obviously indicated the high reservation of ACPS in the membrane formation process. The fact that the O/F ratios in the membrane surface layers were much higher than those in the bulk membrane proved the enrichment of ACPS on the surface. The filterability experiments and water contact angle testing proved the hydrophilicity of the blend membranes. Through a schematic model, the mechanism relating the membrane structure and performance was interpreted. From the observed results, it can be concluded that ACPS acts as a potential candidate material for preparing PVDF membranes with extraordinary hydrophilicity and filterability.
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Synthesis and self-assembly of reactive H-shaped
block copolymers
ZOU Peng, PAN Caiyuan
Front. Chem. China. 2008, 3 (4): 480-484.
https://doi.org/10.1007/s11458-008-0059-3
The H-shaped block copolymers (PTMSPMA)2PEG(PMPSTMSPMA)2 with two compositions, (EG)91-b-(TMSPMA)92 and (EG)455-b-(TMSPMA)176 have been successfully synthesized by atom transfer radical polymerization (ATRP) of tri(methoxylsilyl)propyl methacrylate (TMSPMA) at room temperature in methanol. The initiation system applied was composed of 2,2-bis(methylene ?-bromoisobutyrate)propionyl terminated poly(ethylene glycol) (Br2PEGBr2) with Mn = 4000 or 20000, CuBr and 2,2′-bipyridine. The macroinitiator, Br2PEGBr2, was prepared by the reaction of two hydroxyl groups terminated PEG with 2,2-bis(methylene ?-bromoisobutyrate)propionyl chloride. The NMR spectroscopy and GPC measurements were used to characterize the structure and molecular weight and molecular weight distribution of the resultant copolymers. The H-shaped block copolymers Sam 1 and Sam 2 were self-assembled in DMF/water mixtures and then the trimethoxysilyl groups in PTMSPMA were cross-linked by condensation reaction in the presence of triethylamine. Stable large-compound vesicles with 10 nm diameter of cavities were formed for Sam 1 which contains a short PEG chain. However, the self-assembling of the Sam 2 in the selective solvents resulted in big vesicles aggregates. These two different morphologies of aggregates are attributed to their relative chain length of water soluble PEG. The vesicles formed from Sam1 with short PEG chains have big surface energy which will lead them to self-assemble further, forming large-compound vesicles.
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