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2008 Volume 19 Issue 9
2008, 19(9): 1013-1016
doi: 10.1016/j.cclet.2008.06.003
Abstract:
1,3,5-Trisubstituted pyrazolines were oxidized to the corresponding pyrazoles in high yield with tris (4-bromophenyl) aminium (TBPA+·) hexachloroantimonate in chloroform at room temperature.
1,3,5-Trisubstituted pyrazolines were oxidized to the corresponding pyrazoles in high yield with tris (4-bromophenyl) aminium (TBPA+·) hexachloroantimonate in chloroform at room temperature.
2008, 19(9): 1017-1020
doi: 10.1016/j.cclet.2008.06.004
Abstract:
Highly efficient palladium-catalyzed Heck coupling of aryl nonaflates with electron-rich vinyl ethers, and enamides is described. These reactions afforded exclusively the branched products in good yields. The results indicated that aryl nonaflates are effective alternative to the frequently employed aryl triflates.
Highly efficient palladium-catalyzed Heck coupling of aryl nonaflates with electron-rich vinyl ethers, and enamides is described. These reactions afforded exclusively the branched products in good yields. The results indicated that aryl nonaflates are effective alternative to the frequently employed aryl triflates.
2008, 19(9): 1021-1023
doi: 10.1016/j.cclet.2008.06.002
Abstract:
A novel benzo[1,5] oxazepin-4-one skeleton compound and its four derivatives were synthesized effectively from 1,5-difluoro-2,4-dinitrobenzene (DFDNB) under mild conditions. In the process, four intermediates were synthesized by substitutions of the two fluorine atoms and reductions of the meta-dinitro groups in DFDNB respectively. The results showed that the key for synthesizing the intermediates was the substitution of one of the two fluorine atoms in DFDNB by 3-hydroxy butyric acid ethyl ester first, then the other fluorine atom by morpholine, and then the reduction of the meta-dinitro groups in the substitute by HCOONH4 with Pd/C. The products were purified with silica gel column chromatography, and confirmed by HPLC, LC-MS and 1H NMR. They should contribute to construct the molecular libraries for therapeutic applications.
A novel benzo[1,5] oxazepin-4-one skeleton compound and its four derivatives were synthesized effectively from 1,5-difluoro-2,4-dinitrobenzene (DFDNB) under mild conditions. In the process, four intermediates were synthesized by substitutions of the two fluorine atoms and reductions of the meta-dinitro groups in DFDNB respectively. The results showed that the key for synthesizing the intermediates was the substitution of one of the two fluorine atoms in DFDNB by 3-hydroxy butyric acid ethyl ester first, then the other fluorine atom by morpholine, and then the reduction of the meta-dinitro groups in the substitute by HCOONH4 with Pd/C. The products were purified with silica gel column chromatography, and confirmed by HPLC, LC-MS and 1H NMR. They should contribute to construct the molecular libraries for therapeutic applications.
2008, 19(9): 1024-1026
doi: 10.1016/j.cclet.2008.06.032
Abstract:
Catalyzed by ytterbium (Ⅲ) triflate hydrate[Yb(OTf)3·xH2O], the Michael addition and cycloeondensation of α,β-unsaturated ketones with active methylene compounds to afford the 1,4-adducts and benzo[b]pyran derivatives, respectively were studied.
Catalyzed by ytterbium (Ⅲ) triflate hydrate[Yb(OTf)3·xH2O], the Michael addition and cycloeondensation of α,β-unsaturated ketones with active methylene compounds to afford the 1,4-adducts and benzo[b]pyran derivatives, respectively were studied.
2008, 19(9): 1027-1030
doi: 10.1016/j.cclet.2008.06.021
Abstract:
A convenient, rapid and efficient method for the synthesis of substituted steroidal[6,7-d] thiazoles using microwave-induced organic reaction enhancement chemistry has been developed. The additional features of this methodology include a much faster reaction, easy workup, high yield, high purity of the products and an environment friendly approach.
A convenient, rapid and efficient method for the synthesis of substituted steroidal[6,7-d] thiazoles using microwave-induced organic reaction enhancement chemistry has been developed. The additional features of this methodology include a much faster reaction, easy workup, high yield, high purity of the products and an environment friendly approach.
2008, 19(9): 1031-1034
doi: 10.1016/j.cclet.2008.06.019
Abstract:
Aromatic and alkyl alcohols were oxidized to the corresponding aldehydes or ketones at room temperature with high conversion and selectivity using Oxone® (2KHSO5·KHSO4·K2SO4) as oxidant catalyzed by ruthenium complex Quin-Ru-Quin (where Quin=8-hydroxyquinoline). The reaction time is very short and the preparation of complex is simple.
Aromatic and alkyl alcohols were oxidized to the corresponding aldehydes or ketones at room temperature with high conversion and selectivity using Oxone® (2KHSO5·KHSO4·K2SO4) as oxidant catalyzed by ruthenium complex Quin-Ru-Quin (where Quin=8-hydroxyquinoline). The reaction time is very short and the preparation of complex is simple.
2008, 19(9): 1035-1038
doi: 10.1016/j.cclet.2008.06.018
Abstract:
Six new N4-[bi-(4-fluorophenyl)-methyl]-piperazine thiosemicarbazones 3a-f have been prepared starting from[bi-(4-fluor-ophenyl)-methyl]-piperazine in solvent-free condition under microwave irradiation with excellent yields. Their structures have been determined by elemental analysis, IR, MS and 1H NMR data.
Six new N4-[bi-(4-fluorophenyl)-methyl]-piperazine thiosemicarbazones 3a-f have been prepared starting from[bi-(4-fluor-ophenyl)-methyl]-piperazine in solvent-free condition under microwave irradiation with excellent yields. Their structures have been determined by elemental analysis, IR, MS and 1H NMR data.
2008, 19(9): 1039-1042
doi: 10.1016/j.cclet.2008.06.017
Abstract:
amphiphilic[60]fullerene monoadduet TPF and bisadducts BTPF were synthesized and well-characterized. Their aggregation properties in aqueous solution was investigated by UV-vis and TEM methods. In aqueous solution, monoadduct TPF forms irregularly shaped and some rod-like aggregates, whereas bisadducts BTPF gives spherical aggregates with diameters of 50-150 nm. It indicated that the aggregation properties of amphiphilic fullerene derivatives depend on the number of hydrophilic appendage on the C60 cage.
amphiphilic[60]fullerene monoadduet TPF and bisadducts BTPF were synthesized and well-characterized. Their aggregation properties in aqueous solution was investigated by UV-vis and TEM methods. In aqueous solution, monoadduct TPF forms irregularly shaped and some rod-like aggregates, whereas bisadducts BTPF gives spherical aggregates with diameters of 50-150 nm. It indicated that the aggregation properties of amphiphilic fullerene derivatives depend on the number of hydrophilic appendage on the C60 cage.
2008, 19(9): 1043-1046
doi: 10.1016/j.cclet.2008.06.016
Abstract:
The Knoevenagel condensation of aromatic aldehydes with active methylene compound proceeded efficiently in polyethylene glycol at room temperature with L-proline as catalyst. The yield is high and the products had E-isomer dominantly. Polyethylene glycol containing L-proline could be recycled and reused for several times without noticeably decreasing in productivity.
The Knoevenagel condensation of aromatic aldehydes with active methylene compound proceeded efficiently in polyethylene glycol at room temperature with L-proline as catalyst. The yield is high and the products had E-isomer dominantly. Polyethylene glycol containing L-proline could be recycled and reused for several times without noticeably decreasing in productivity.
2008, 19(9): 1047-1050
doi: 10.1016/j.cclet.2008.06.029
Abstract:
1,4-Dienyl selenides can be stereoselectively synthesized in one pot under mild conditions in good yields by the palladium-catalyzed hydrostannylation of acetylenic selenides, followed by Stille coupling with allylic bromides.
1,4-Dienyl selenides can be stereoselectively synthesized in one pot under mild conditions in good yields by the palladium-catalyzed hydrostannylation of acetylenic selenides, followed by Stille coupling with allylic bromides.
2008, 19(9): 1051-1054
doi: 10.1016/j.cclet.2008.06.015
Abstract:
A novel type of chiral molecular tweezers has been designed and synthesized by using deoxycholic acid as backbone and ethanoyl and the chiral unsymmetrical urea unit as arms. Their structures were characterized by 1H NMR, IR, MS spectra and elemental analysis. These molecular tweezers showed good binding ability for neutral molecules and chiral molecules.
A novel type of chiral molecular tweezers has been designed and synthesized by using deoxycholic acid as backbone and ethanoyl and the chiral unsymmetrical urea unit as arms. Their structures were characterized by 1H NMR, IR, MS spectra and elemental analysis. These molecular tweezers showed good binding ability for neutral molecules and chiral molecules.
2008, 19(9): 1055-1058
doi: 10.1016/j.cclet.2008.06.028
Abstract:
Glyoxylic acid (5 mol%) performs as a novel highly water-soluble catalyst for the synthesis of 2-aryl-l-arylmethyl-lH-benzimidazoles from a wide range of substituted o-phenylenediamines and various substituted aldehydes in good to excellent isolated yields (85-95%) using water as solvent at ambient temperature. The remarkable advantages offered by this method are easily and inexpensive available catalyst, simple procedure, mild conditions, much faster (20-40 min) reactions and excellent yields of products.
Glyoxylic acid (5 mol%) performs as a novel highly water-soluble catalyst for the synthesis of 2-aryl-l-arylmethyl-lH-benzimidazoles from a wide range of substituted o-phenylenediamines and various substituted aldehydes in good to excellent isolated yields (85-95%) using water as solvent at ambient temperature. The remarkable advantages offered by this method are easily and inexpensive available catalyst, simple procedure, mild conditions, much faster (20-40 min) reactions and excellent yields of products.
2008, 19(9): 1059-1062
doi: 10.1016/j.cclet.2008.05.041
Abstract:
The dehydrogenation of isobutane (IB) to produce isobutene coupled with reverse water gas shift in the presence of carbon dioxide was investigated over the catalyst Cr2O3 supported on active carbon (Cr2O3/AC). The results illustrated that isobutane conversion and isobutene yield can be enhanced through the reaction coupling in the presence of carbon dioxide. Moreover, carbon dioxide can partially eliminate carbonaceous deposition on the catalyst and keep the active phase (Cr2O3), which are then helpful to alleviate the catalyst deactivation.
The dehydrogenation of isobutane (IB) to produce isobutene coupled with reverse water gas shift in the presence of carbon dioxide was investigated over the catalyst Cr2O3 supported on active carbon (Cr2O3/AC). The results illustrated that isobutane conversion and isobutene yield can be enhanced through the reaction coupling in the presence of carbon dioxide. Moreover, carbon dioxide can partially eliminate carbonaceous deposition on the catalyst and keep the active phase (Cr2O3), which are then helpful to alleviate the catalyst deactivation.
2008, 19(9): 1063-1067
doi: 10.1016/j.cclet.2008.06.031
Abstract:
Selective protection of one of the hydroxyl group in 1, n-symmetrical diols is achieved by P2O5/SiO2-catalyzed reaction of the diol with dihydropyran under solvent-free conditions at room temperature. This selective protection is simple and it occurred under economically cheap conditions in high yield. The deprotected diol is simply obtained by refluxing of this compound in methanol using the same catalyst without any byproduct formation or additional purifications.
Selective protection of one of the hydroxyl group in 1, n-symmetrical diols is achieved by P2O5/SiO2-catalyzed reaction of the diol with dihydropyran under solvent-free conditions at room temperature. This selective protection is simple and it occurred under economically cheap conditions in high yield. The deprotected diol is simply obtained by refluxing of this compound in methanol using the same catalyst without any byproduct formation or additional purifications.
2008, 19(9): 1068-1070
doi: 10.1016/j.cclet.2008.06.027
Abstract:
The protected 2S,4R-2-amino-4-methyldecanoic acid, a proposed component of culicinins has been synthesized over 10 steps and in total 28% yields using Wittig reaction and SchÖllkopf amino acid synthesis as key steps.
The protected 2S,4R-2-amino-4-methyldecanoic acid, a proposed component of culicinins has been synthesized over 10 steps and in total 28% yields using Wittig reaction and SchÖllkopf amino acid synthesis as key steps.
2008, 19(9): 1071-1074
doi: 10.1016/j.cclet.2008.06.009
Abstract:
A series of novel hindered amine light stabilizers containing an N-halamine moiety were designed and synthesized. Their structures were characterized by FT-IR, 1H NMR, and MS. The compounds were tested for antibacterial activity against Candida albicans, Staphylococcus aureus, and Escherichia coli. At a concentration of 0.5 mmool/L, these compounds all exhibited satisfactory antibacterial activity against all the three types of bacteria.
A series of novel hindered amine light stabilizers containing an N-halamine moiety were designed and synthesized. Their structures were characterized by FT-IR, 1H NMR, and MS. The compounds were tested for antibacterial activity against Candida albicans, Staphylococcus aureus, and Escherichia coli. At a concentration of 0.5 mmool/L, these compounds all exhibited satisfactory antibacterial activity against all the three types of bacteria.
2008, 19(9): 1075-1079
doi: 10.1016/j.cclet.2008.06.008
Abstract:
A series of novel derivatives of 4, 5, 6, 7-tetrahydrothieno[3,2-c] pyridine were synthesized and strucmrally characterized by 1H NMR and MS. Their in vivo anti-platelet aggregation activities were evaluated. A 3D-QSAR was performed using the CoMFA and the CoMSIA. This model provided useful guidelines for novel anti-platelet thienopyridines design.
A series of novel derivatives of 4, 5, 6, 7-tetrahydrothieno[3,2-c] pyridine were synthesized and strucmrally characterized by 1H NMR and MS. Their in vivo anti-platelet aggregation activities were evaluated. A 3D-QSAR was performed using the CoMFA and the CoMSIA. This model provided useful guidelines for novel anti-platelet thienopyridines design.
2008, 19(9): 1080-1082
doi: 10.1016/j.cclet.2008.06.005
Abstract:
A new diterpenoid, named populusol A (1), was isolated from the methanolic extraction of the stem bark of Populus davidiana. The structure was elucidated on the basis of extensive 1D and 2D NMR as well as HRFAB-MS spectroscopic analysis.
A new diterpenoid, named populusol A (1), was isolated from the methanolic extraction of the stem bark of Populus davidiana. The structure was elucidated on the basis of extensive 1D and 2D NMR as well as HRFAB-MS spectroscopic analysis.
2008, 19(9): 1083-1085
doi: 10.1016/j.cclet.2008.06.006
Abstract:
A new anthraquinone glycoside 1, along with a known anthraquinone glycoside aurantio-obtusin-6-O-β-D-glucopyranoside 2, were isolated from the seeds of Cassia obtusifolia. On the basis of spectral and chemical evidences, the structure of 1 was established as 1-demethylaurantio-obtusin-2-O-β-D-glucopyranoside. Moreover, the 13C NMR of 2 was assigned totally and correctly for the first time based on the two-dimensional NMR.
A new anthraquinone glycoside 1, along with a known anthraquinone glycoside aurantio-obtusin-6-O-β-D-glucopyranoside 2, were isolated from the seeds of Cassia obtusifolia. On the basis of spectral and chemical evidences, the structure of 1 was established as 1-demethylaurantio-obtusin-2-O-β-D-glucopyranoside. Moreover, the 13C NMR of 2 was assigned totally and correctly for the first time based on the two-dimensional NMR.
2008, 19(9): 1086-1088
doi: 10.1016/j.cclet.2008.06.026
Abstract:
Two new C27-steroidal glycosides were isolated from the fibrous roots of Ophiopogon japonicus. The spectral analysis and chemical evidence revealed their chemical structures to be (25R)-spirost-5,14-dien-3β-yl-O-α-L-rhanmopyranosyl-(1→2)-β-D-xylopyranosyl-(1→4)-β-D-glucopyranoside (1) and ophiogenin 3-O-β-D-glucopyranoside (2).
Two new C27-steroidal glycosides were isolated from the fibrous roots of Ophiopogon japonicus. The spectral analysis and chemical evidence revealed their chemical structures to be (25R)-spirost-5,14-dien-3β-yl-O-α-L-rhanmopyranosyl-(1→2)-β-D-xylopyranosyl-(1→4)-β-D-glucopyranoside (1) and ophiogenin 3-O-β-D-glucopyranoside (2).
2008, 19(9): 1089-1092
doi: 10.1016/j.cclet.2008.06.025
Abstract:
A new β-resorcylic maerolide, 5'-hydroxyzearalenol (1), was isolated from the culture broth of a marine-derived fungus Fusarium sp. 05ABR26. Three known compounds, zearalenone (2), 8'-hydroxyzearalenone (3) and zearalenol (4) were also isolated. The structure and relative stereochemistry of 1 were elucidated on the basis of spectroscopic data and single-crystal X-ray diffraction data. Compound 2 displayed potent inhibitory activity against Pyricularia oryzae with a MIC value of 6.25 μg/mL, while compound 3 was much less active; however, 1 and 4 showed no obvious activity.
A new β-resorcylic maerolide, 5'-hydroxyzearalenol (1), was isolated from the culture broth of a marine-derived fungus Fusarium sp. 05ABR26. Three known compounds, zearalenone (2), 8'-hydroxyzearalenone (3) and zearalenol (4) were also isolated. The structure and relative stereochemistry of 1 were elucidated on the basis of spectroscopic data and single-crystal X-ray diffraction data. Compound 2 displayed potent inhibitory activity against Pyricularia oryzae with a MIC value of 6.25 μg/mL, while compound 3 was much less active; however, 1 and 4 showed no obvious activity.
2008, 19(9): 1093-1095
doi: 10.1016/j.cclet.2008.06.024
Abstract:
6-(5-Carboxyl-2-methoxyphenyl)-apigenin (1), a new flavonoid, was isolated from the 60% ethanol extract of Selaginella uncinata (Desv.) Spring. Its structure was established by spectroscopic methods. Compound 1 represents the first example of the flavonoids possessing a benzoic acid substituent at C-6.
6-(5-Carboxyl-2-methoxyphenyl)-apigenin (1), a new flavonoid, was isolated from the 60% ethanol extract of Selaginella uncinata (Desv.) Spring. Its structure was established by spectroscopic methods. Compound 1 represents the first example of the flavonoids possessing a benzoic acid substituent at C-6.
2008, 19(9): 1096-1098
doi: 10.1016/j.cclet.2008.06.020
Abstract:
Two new ent-kaurane diterpenoids, minheryins H (1) and I (2), were isolated from the leaves of lsodon henryi. Their structures were elucidated by means of spectroscopic analysis, including 2D NMR spectra.
Two new ent-kaurane diterpenoids, minheryins H (1) and I (2), were isolated from the leaves of lsodon henryi. Their structures were elucidated by means of spectroscopic analysis, including 2D NMR spectra.
2008, 19(9): 1099-1102
doi: 10.1016/j.cclet.2008.06.033
Abstract:
Two new acetylated ginsenosides, 20(S)-protopanaxatriol-6-O-α-L-rhamnopyranosyl (1→2)-β-D-6'-O-acetylglucopyranoside (1) and 20(R)-protopanaxatriol-6-O-α-L-rhamnopyranosyl (1→2)-β-D-6'-O-acetylglucopyranoside (2), were isolated from the roots of Panax quinquefolium The structures were elucidated on the basis of spectroscopic techniques and chemical means.
Two new acetylated ginsenosides, 20(S)-protopanaxatriol-6-O-α-L-rhamnopyranosyl (1→2)-β-D-6'-O-acetylglucopyranoside (1) and 20(R)-protopanaxatriol-6-O-α-L-rhamnopyranosyl (1→2)-β-D-6'-O-acetylglucopyranoside (2), were isolated from the roots of Panax quinquefolium The structures were elucidated on the basis of spectroscopic techniques and chemical means.
2008, 19(9): 1103-1107
doi: 10.1016/j.cclet.2008.06.012
Abstract:
A novel kinetic method for determination of trace amounts of cobalt ion was proposed and validated. The method is based on adding malic acid into classical Belousov-Zhabotinskii (B-Z) oscillating chemical system to form a double substrate one. The results showed that when the concentration of cobalt ion was in the range of 5.27×10-8 to 5.37×10-12mol L-1 the change of the oscillating period was directly proportional to the negative logarithm of cobalt ion concentration. The sensitivity and precision of the developed method were quite satisfactory. The limit of detection was down to 5.20×10-13 mol L-1 which was a highest sensitivity found for determination of metal ions using oscillating chemical reaction so far. Some factors influencing the determination were also examined. The method has been successfully used to determine cobalt ion in vitamin B12 injection.
A novel kinetic method for determination of trace amounts of cobalt ion was proposed and validated. The method is based on adding malic acid into classical Belousov-Zhabotinskii (B-Z) oscillating chemical system to form a double substrate one. The results showed that when the concentration of cobalt ion was in the range of 5.27×10-8 to 5.37×10-12mol L-1 the change of the oscillating period was directly proportional to the negative logarithm of cobalt ion concentration. The sensitivity and precision of the developed method were quite satisfactory. The limit of detection was down to 5.20×10-13 mol L-1 which was a highest sensitivity found for determination of metal ions using oscillating chemical reaction so far. Some factors influencing the determination were also examined. The method has been successfully used to determine cobalt ion in vitamin B12 injection.
2008, 19(9): 1108-1110
doi: 10.1016/j.cclet.2008.06.010
Abstract:
In this research, an unusually dimeric G-quadruplex of d(GGGTGGGTGGGTGGGT) (Sl), the potent nanomolar HIV-1 integrase inhibitor, was detected by nuclear magnetic resonance (NMR). This result has been confirmed by electrospray ionization mass spectrometry (ESI-MS) and circular dichroism (CD).
In this research, an unusually dimeric G-quadruplex of d(GGGTGGGTGGGTGGGT) (Sl), the potent nanomolar HIV-1 integrase inhibitor, was detected by nuclear magnetic resonance (NMR). This result has been confirmed by electrospray ionization mass spectrometry (ESI-MS) and circular dichroism (CD).
2008, 19(9): 1111-1114
doi: 10.1016/j.cclet.2008.05.040
Abstract:
In this work, the adsorption and diffusion behavior of nitrate ions into polycationic P(DMAEMA/HEMA) hydrogels is analyzed. Experimental results indicated that nitrate ions can be removed efficiently from aqueous solutions. Adsorption isotherm of gels was well according to the Langmuir and Langmuir-Freundlich models. At the same time, the diffusion behavior of nitrate ions from P(DMAEMA/HEMA) hydrogels was investigated. The diffusion coefficients are strongly influenced by the changes of temperature and pH value of solutions. At the same time, D does not depend on the gels cross-linking ratio and initial solute concentration.
In this work, the adsorption and diffusion behavior of nitrate ions into polycationic P(DMAEMA/HEMA) hydrogels is analyzed. Experimental results indicated that nitrate ions can be removed efficiently from aqueous solutions. Adsorption isotherm of gels was well according to the Langmuir and Langmuir-Freundlich models. At the same time, the diffusion behavior of nitrate ions from P(DMAEMA/HEMA) hydrogels was investigated. The diffusion coefficients are strongly influenced by the changes of temperature and pH value of solutions. At the same time, D does not depend on the gels cross-linking ratio and initial solute concentration.
2008, 19(9): 1115-1118
doi: 10.1016/j.cclet.2008.06.001
Abstract:
A lipoplex (i.e., pDNA#1/lipid complex and transfection reagent for pDNA delivery) containing galactosylceramide (GalCer) and an amidine-bearing lipid (TRX) was examined whether the bound pDNA was specifically ingested by hepatocyte via asialoglycoprotein receptor (ASGPR) and then expressed protein. Gel electrophoresis and small-angle X-ray scattering (SAXS) confirmed that the TRX-GalCer liposome#2 complexed with pDNA and the resultant lipoplex took a hexagonally packed inverted cylinder structure when the GalCer composition was less than 20 wt.% of the total lipid. When the lipoplex carrying pGL3 (luciferase-cording pDNA) was administrated to HepG2, the luciferase activity was increased with increasing the GalCer composition until it reached 3 wt.% and then decreased upon further addition of GalCer. When we added galactose itself as a competitor, the luciferase activity was decreased, while glucose did not show such decrease, suggesting that HepG2 ingested the lipoplex via ASGPR-mediated endocytosis. This paper indicated that the hexagonally packed inverted cylinder structures of lipoplex may not always provide excellent transfection and presented a possibility that the TRX lipoplex#3 can obtain a cellular-targeting ability through the receptors for oligosaccharide.
A lipoplex (i.e., pDNA#1/lipid complex and transfection reagent for pDNA delivery) containing galactosylceramide (GalCer) and an amidine-bearing lipid (TRX) was examined whether the bound pDNA was specifically ingested by hepatocyte via asialoglycoprotein receptor (ASGPR) and then expressed protein. Gel electrophoresis and small-angle X-ray scattering (SAXS) confirmed that the TRX-GalCer liposome#2 complexed with pDNA and the resultant lipoplex took a hexagonally packed inverted cylinder structure when the GalCer composition was less than 20 wt.% of the total lipid. When the lipoplex carrying pGL3 (luciferase-cording pDNA) was administrated to HepG2, the luciferase activity was increased with increasing the GalCer composition until it reached 3 wt.% and then decreased upon further addition of GalCer. When we added galactose itself as a competitor, the luciferase activity was decreased, while glucose did not show such decrease, suggesting that HepG2 ingested the lipoplex via ASGPR-mediated endocytosis. This paper indicated that the hexagonally packed inverted cylinder structures of lipoplex may not always provide excellent transfection and presented a possibility that the TRX lipoplex#3 can obtain a cellular-targeting ability through the receptors for oligosaccharide.
2008, 19(9): 1119-1122
doi: 10.1016/j.cclet.2008.06.011
Abstract:
N-Octadecyl-N'-maleoyl-L-phenylalanine (ODMA-L-Phe) was synthesized through the condensation, deprotection and aeid-ylation reaction of BOC-L-phenylalanine, octadecylamine and maleic anhydride. ODMA-L-Phe can self-assemble in some organic solvents and turned them into thermally reversible physical supramolecular organogels. The morphology of ODMA-L-Phe aggregates was characterized by polarized optical microscopy (POM) and field emission scanning electron microscope (FE-SEM). The aggregates of ODMA-L-Phe were needle-like fibrils with diameters of approximately 100-200 nm. The mechanism of ODMA-L-Phe self-assembly in organic solvents was investigated using 1H NMR and circular dichroism (CD). The results indicated that hydrogen bonding was one of the main driving forces for the self-assembly of ODMA-L-Phe.
N-Octadecyl-N'-maleoyl-L-phenylalanine (ODMA-L-Phe) was synthesized through the condensation, deprotection and aeid-ylation reaction of BOC-L-phenylalanine, octadecylamine and maleic anhydride. ODMA-L-Phe can self-assemble in some organic solvents and turned them into thermally reversible physical supramolecular organogels. The morphology of ODMA-L-Phe aggregates was characterized by polarized optical microscopy (POM) and field emission scanning electron microscope (FE-SEM). The aggregates of ODMA-L-Phe were needle-like fibrils with diameters of approximately 100-200 nm. The mechanism of ODMA-L-Phe self-assembly in organic solvents was investigated using 1H NMR and circular dichroism (CD). The results indicated that hydrogen bonding was one of the main driving forces for the self-assembly of ODMA-L-Phe.
2008, 19(9): 1123-1126
doi: 10.1016/j.cclet.2008.06.022
Abstract:
The objectives of the present research are synthesizing three-dimensional (3D) nickel nanostructures and investigating their magnetic properties. Thus a template-free method was used to prepare 3D dandelion-like nickel nanostructures via reducing of nickel chloride with hydrazine hydrate in ethylene glycol solution at 100℃. The resulting Ni nanostructures were characterized by means of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected-area electron diffraction (SAED). And the magnetic properties of the 3D Ni nanostructures were measured as well. Results indicated that solvothermal process could be successfully used to prepare 3D dandelion-like nanostruetures of Ni at a relatively mild temperature of 100℃. And the conclusions were made as follows:as-prepared Ni samples had obvious shape anisotropy and were composed of fine nanocrystallites, while they had significantly enhanced ferromagnetic properties than bulk Ni and Ni nanoparticles.
The objectives of the present research are synthesizing three-dimensional (3D) nickel nanostructures and investigating their magnetic properties. Thus a template-free method was used to prepare 3D dandelion-like nickel nanostructures via reducing of nickel chloride with hydrazine hydrate in ethylene glycol solution at 100℃. The resulting Ni nanostructures were characterized by means of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected-area electron diffraction (SAED). And the magnetic properties of the 3D Ni nanostructures were measured as well. Results indicated that solvothermal process could be successfully used to prepare 3D dandelion-like nanostruetures of Ni at a relatively mild temperature of 100℃. And the conclusions were made as follows:as-prepared Ni samples had obvious shape anisotropy and were composed of fine nanocrystallites, while they had significantly enhanced ferromagnetic properties than bulk Ni and Ni nanoparticles.
2008, 19(9): 1127-1130
doi: 10.1016/j.cclet.2008.05.039
Abstract:
The monomer 2,6,12-triaminotriptyeene was synthesized and the structure was confirmed by IR and 1H NMR spectra. Hyperbranched polyimides modified with different terminal groups were obtained from precursors, anhydride-and amino-terminated hyperbranched poly(amic acid)s from polymerization of A2+B3 system. From gel permeation chromatogram (GPC) characterization, representative products had high molecular weight. All polymers had good solubility in CHCl3, DMF and tetrahydrofuran (THF), and performed no detective Tgs in the range of 50-300℃ and high TdS above 455℃ when 5% weight loss.
The monomer 2,6,12-triaminotriptyeene was synthesized and the structure was confirmed by IR and 1H NMR spectra. Hyperbranched polyimides modified with different terminal groups were obtained from precursors, anhydride-and amino-terminated hyperbranched poly(amic acid)s from polymerization of A2+B3 system. From gel permeation chromatogram (GPC) characterization, representative products had high molecular weight. All polymers had good solubility in CHCl3, DMF and tetrahydrofuran (THF), and performed no detective Tgs in the range of 50-300℃ and high TdS above 455℃ when 5% weight loss.
2008, 19(9): 1131-1134
doi: 10.1016/j.cclet.2008.06.007
Abstract:
In this work, 4-methoxylcirmamoyl chloride was reacted with a commercial hyperbranched polymer (Boltom~TM H30) to prepare a hyperbranched photosensitive polymer (H30-Ci). The polymer was characterized by UV absorption spectrum and 1H-NMR spectrum. After processed by Linearly Polarized Polymerization (LPP) method, the spin-coated films of H30-Ci were used as photo-alignment layers to assemble liquid crystal (LC) cells containing nematic liquid crystal (5CB). The observation by polarized microscope showed that the H30-Ci blended with a linear polymer (BP-AN-Ci) photo-alignment layers could align LC molecules in a very uniform way.
In this work, 4-methoxylcirmamoyl chloride was reacted with a commercial hyperbranched polymer (Boltom~TM H30) to prepare a hyperbranched photosensitive polymer (H30-Ci). The polymer was characterized by UV absorption spectrum and 1H-NMR spectrum. After processed by Linearly Polarized Polymerization (LPP) method, the spin-coated films of H30-Ci were used as photo-alignment layers to assemble liquid crystal (LC) cells containing nematic liquid crystal (5CB). The observation by polarized microscope showed that the H30-Ci blended with a linear polymer (BP-AN-Ci) photo-alignment layers could align LC molecules in a very uniform way.
2008, 19(9): 1135-1138
doi: 10.1016/j.cclet.2008.06.023
Abstract:
The stereoselectivity of some Diels-Alder reactions was investigated by means of ABEEM-Óπ model. Combined with local hard-soft and acid-base (HSAB) principle, we made reasonable explanation by calculating local softness of atom and bond regions for the stereoselectivity of four Diels-Alder reactions involving cyclopentadiene.
The stereoselectivity of some Diels-Alder reactions was investigated by means of ABEEM-Óπ model. Combined with local hard-soft and acid-base (HSAB) principle, we made reasonable explanation by calculating local softness of atom and bond regions for the stereoselectivity of four Diels-Alder reactions involving cyclopentadiene.
