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2008 Volume 19 Issue 2
2008, 19(2): 127-129
doi: 10.1016/j.cclet.2007.12.002
Abstract:
A novel bifunctional glycolipid which carried a cluster of thiogalactosides as the bepatocyte targeting ligand for gene delivery was prepared.Hexa-antennary alcohol 1 was used as the core scaffold to attach a cholesterol molecule by a poly (ethylene glycol) chain, while its remaining branches were linked with five acetylgalactosides, which would be deacetylated later to produce pentaantennary galaetoside.Liposome containing the galactoside showed high affinity and transfection activity in hepatoma cells HepG2.
A novel bifunctional glycolipid which carried a cluster of thiogalactosides as the bepatocyte targeting ligand for gene delivery was prepared.Hexa-antennary alcohol 1 was used as the core scaffold to attach a cholesterol molecule by a poly (ethylene glycol) chain, while its remaining branches were linked with five acetylgalactosides, which would be deacetylated later to produce pentaantennary galaetoside.Liposome containing the galactoside showed high affinity and transfection activity in hepatoma cells HepG2.
2008, 19(2): 130-132
doi: 10.1016/j.cclet.2007.11.016
Abstract:
Semi-synthesis of paclitaxel was achieved in four steps from 10-deacetylbaccatin Ⅲ (10-DAB Ⅲ).The key steps are the regioselective protection at the hydroxyl group at C-7 of 10-DAB HI, using 1, 1'-thiocarbonyldiimidazole as a selective reagent, and the deprotection of the protected paclitaxel with a mixture of p-toluenesulfonic acid and 0.1 mol/L aqueous hydrochloride.
Semi-synthesis of paclitaxel was achieved in four steps from 10-deacetylbaccatin Ⅲ (10-DAB Ⅲ).The key steps are the regioselective protection at the hydroxyl group at C-7 of 10-DAB HI, using 1, 1'-thiocarbonyldiimidazole as a selective reagent, and the deprotection of the protected paclitaxel with a mixture of p-toluenesulfonic acid and 0.1 mol/L aqueous hydrochloride.
2008, 19(2): 133-136
doi: 10.1016/j.cclet.2007.11.027
Abstract:
The preparation of hitherto unknown steroidal heterocycles containing pyrazole fused to 6, 7-position of the steroidal nucleus is described.These heterocycles were prepared by the action of Vilsmeier reagent with steroidal semicarbazones in DMF.The slructure of the compounds has been established on the basis of their elemental analysis and spectral data.A general mechanistic scheme for these reactions is also suggested based on current and previous results.
The preparation of hitherto unknown steroidal heterocycles containing pyrazole fused to 6, 7-position of the steroidal nucleus is described.These heterocycles were prepared by the action of Vilsmeier reagent with steroidal semicarbazones in DMF.The slructure of the compounds has been established on the basis of their elemental analysis and spectral data.A general mechanistic scheme for these reactions is also suggested based on current and previous results.
2008, 19(2): 137-140
doi: 10.1016/j.cclet.2007.10.035
Abstract:
N-(2-Hydroxypropyl) methacrylamide copolymer-5-fluorouracil (PHPMA-FU) conjugates were synthesized by a novel and simplified synthetic mute, and characterized by UV, FTIR and HPLC analyses.The conjugated content of 5-fluorouracil (5-FU) was 3.41±0.07 wt%.The stabilities of PHPMA-FU conjugates under different conditions were studied.The results showed that HPMA copolymer was a potential carrier for tumor-targeting delivery of 5-FU.
N-(2-Hydroxypropyl) methacrylamide copolymer-5-fluorouracil (PHPMA-FU) conjugates were synthesized by a novel and simplified synthetic mute, and characterized by UV, FTIR and HPLC analyses.The conjugated content of 5-fluorouracil (5-FU) was 3.41±0.07 wt%.The stabilities of PHPMA-FU conjugates under different conditions were studied.The results showed that HPMA copolymer was a potential carrier for tumor-targeting delivery of 5-FU.
2008, 19(2): 141-145
doi: 10.1016/j.cclet.2007.11.004
Abstract:
A novel high molecular weight functional polyacetylene bearing oxadiazole group as a pendant, poly{4-[2-(4-octoxyphenyl)-1, 3, 4-oxadiazolyl]-benzenyloxypropynylene}, was synthesized by[Rh (nbd) Cl]2-Et3N catalyst.The polymer was soluble in common organic solvents such as CHCl3 and THE The structures and properties of monomer and polymer were characterized and evaluated with FTIR, NMR, UV, TGA, GPC, and CV, respectively.The results show that the polymer possesses high thermal stability and well electron-injection property.
A novel high molecular weight functional polyacetylene bearing oxadiazole group as a pendant, poly{4-[2-(4-octoxyphenyl)-1, 3, 4-oxadiazolyl]-benzenyloxypropynylene}, was synthesized by[Rh (nbd) Cl]2-Et3N catalyst.The polymer was soluble in common organic solvents such as CHCl3 and THE The structures and properties of monomer and polymer were characterized and evaluated with FTIR, NMR, UV, TGA, GPC, and CV, respectively.The results show that the polymer possesses high thermal stability and well electron-injection property.
2008, 19(2): 146-148
doi: 10.1016/j.cclet.2007.11.017
Abstract:
Macroporous resin (D201)-supported quartemary ammonium bisulfate (D201-HSO4) was prepared and effectively used in catalyzing the hydrolysis of epoxides or aziridines under mild and non-metal conditions to give the corresponding 1, 2-diols and β-amino alcohols in high yields.The catalyst was facilely prepared and recyclable.
Macroporous resin (D201)-supported quartemary ammonium bisulfate (D201-HSO4) was prepared and effectively used in catalyzing the hydrolysis of epoxides or aziridines under mild and non-metal conditions to give the corresponding 1, 2-diols and β-amino alcohols in high yields.The catalyst was facilely prepared and recyclable.
2008, 19(2): 149-152
doi: 10.1016/j.cclet.2007.11.025
Abstract:
A series of novel nitric oxide-donating sixalkoxyl biphenyl derivatives (14a-1) were synthesized by coupling furoxan with alkoxyl biphenyl skeleton using amino acids as the spacers, and their cytotoxicity against HepG2 cells in vitro were evaluated by MTr method.It was found that 14c, 14d, 14f, 14i, 14j and 14k showed more potent cytotoxic activities than control 5-fluorouracil.NO release assay of target compounds indicated that the maximum amount of NO released by most active compounds 14c and 14j was about 6×10-2μmol/L, whereas 14a and 14h with very weak activity only released NO of 1×10-2μmol/L.
A series of novel nitric oxide-donating sixalkoxyl biphenyl derivatives (14a-1) were synthesized by coupling furoxan with alkoxyl biphenyl skeleton using amino acids as the spacers, and their cytotoxicity against HepG2 cells in vitro were evaluated by MTr method.It was found that 14c, 14d, 14f, 14i, 14j and 14k showed more potent cytotoxic activities than control 5-fluorouracil.NO release assay of target compounds indicated that the maximum amount of NO released by most active compounds 14c and 14j was about 6×10-2μmol/L, whereas 14a and 14h with very weak activity only released NO of 1×10-2μmol/L.
2008, 19(2): 153-156
doi: 10.1016/j.cclet.2007.12.009
Abstract:
An efficient and novel procedure for the preparation of pyrazolo[3, 4-b]pyridine derivatives through multi-component reaction of aldehyde, 5-amino-3-methyl-1-phenylpyrazole and malononitrile or eyanoaeetate in[bmim][BF4] is described in this paper.Advantages of the method presented here include mild conditions, high yields together with a green nature and ease of recovery and reuse of the reaction medium.
An efficient and novel procedure for the preparation of pyrazolo[3, 4-b]pyridine derivatives through multi-component reaction of aldehyde, 5-amino-3-methyl-1-phenylpyrazole and malononitrile or eyanoaeetate in[bmim][BF4] is described in this paper.Advantages of the method presented here include mild conditions, high yields together with a green nature and ease of recovery and reuse of the reaction medium.
2008, 19(2): 157-160
doi: 10.1016/j.cclet.2007.11.013
Abstract:
A new hypocrellin B (HB) derivative bearing a bispyrrolecarboxamide-containing side chain was synthesized, which presents improved absorptivity in phototherapeutic window than Hb and affinity feature towards dsDNA.
A new hypocrellin B (HB) derivative bearing a bispyrrolecarboxamide-containing side chain was synthesized, which presents improved absorptivity in phototherapeutic window than Hb and affinity feature towards dsDNA.
2008, 19(2): 161-165
doi: 10.1016/j.cclet.2007.10.056
Abstract:
A novel deamination of 2-alkyl/aryl 3-amino-4(3H)-qninazolinones series using aqueous KMnO4 under thermal condition and microwave irradiation is described.Compared to thermal condition, significantly higher yields in much shorter times were observedfor reactions under microwave irradiation.A plausible mechanism has been proposed for the oxidative water-promoted deamination.
A novel deamination of 2-alkyl/aryl 3-amino-4(3H)-qninazolinones series using aqueous KMnO4 under thermal condition and microwave irradiation is described.Compared to thermal condition, significantly higher yields in much shorter times were observedfor reactions under microwave irradiation.A plausible mechanism has been proposed for the oxidative water-promoted deamination.
2008, 19(2): 166-168
doi: 10.1016/j.cclet.2007.12.013
Abstract:
In the quest for novel PPARα/γ dual agonists as putative drugs for the treatment of type 2 diabetes and dyslipidemia, we designed and synthesized a series of urea acetates as potential PPARα/γ dual agonists.The structure of the target compounds, intermediates were characterized by 1H NMR, HRMS.
In the quest for novel PPARα/γ dual agonists as putative drugs for the treatment of type 2 diabetes and dyslipidemia, we designed and synthesized a series of urea acetates as potential PPARα/γ dual agonists.The structure of the target compounds, intermediates were characterized by 1H NMR, HRMS.
2008, 19(2): 169-171
doi: 10.1016/j.cclet.2007.12.016
Abstract:
Tetrahydroisoquinoline derivatives were synthesized and their multidrug resistance reversal activities were evaluated in vitro.The results showed that some of the synthetic compounds had higher multidrug resistance (MDR) reversal activities than verapamil.
Tetrahydroisoquinoline derivatives were synthesized and their multidrug resistance reversal activities were evaluated in vitro.The results showed that some of the synthetic compounds had higher multidrug resistance (MDR) reversal activities than verapamil.
2008, 19(2): 172-174
doi: 10.1016/j.cclet.2007.11.031
Abstract:
A short and convergent approach for the synthesis of shikalkin (dl-shikonin) is presented.Stobbe reaction was employed to construct the aromatic skeleton 6.This is followed by a practical method to prepare the key epoxides 9 from aldehydes 8 in high yield.Finally, shikalkin is achieved by CJrignard reaction and oxidation.
A short and convergent approach for the synthesis of shikalkin (dl-shikonin) is presented.Stobbe reaction was employed to construct the aromatic skeleton 6.This is followed by a practical method to prepare the key epoxides 9 from aldehydes 8 in high yield.Finally, shikalkin is achieved by CJrignard reaction and oxidation.
2008, 19(2): 175-179
doi: 10.1016/j.cclet.2007.12.014
Abstract:
The addition of α-keto amides as a NH-acid to alkyl propiolates and dialkyl acetylenedicarboxylates in the presence of a catalytic amount of triphenylphosphine gives the corresponding substituted alkyl acrylates.
The addition of α-keto amides as a NH-acid to alkyl propiolates and dialkyl acetylenedicarboxylates in the presence of a catalytic amount of triphenylphosphine gives the corresponding substituted alkyl acrylates.
2008, 19(2): 180-182
doi: 10.1016/j.cclet.2007.12.001
Abstract:
Two new compounds vernonioside S and vernoniether S were isolated from the stem of Vernonia cumingiana, and theirstructures were elucidated on the basis of spectroscopic evidences.
Two new compounds vernonioside S and vernoniether S were isolated from the stem of Vernonia cumingiana, and theirstructures were elucidated on the basis of spectroscopic evidences.
2008, 19(2): 183-186
doi: 10.1016/j.cclet.2007.12.004
Abstract:
Two new limonoid-type triterpenoids, named 12-o-ethyl-l-deacetylnimbolinin B and 1-o-tigloyl-1-o-debenzoylohchinal, havebeen isolated from the fruit of Melia toosendan Sieb.et Zucc.Their structures were elucidated by spectral methods, including 2D-NMR spectra.
Two new limonoid-type triterpenoids, named 12-o-ethyl-l-deacetylnimbolinin B and 1-o-tigloyl-1-o-debenzoylohchinal, havebeen isolated from the fruit of Melia toosendan Sieb.et Zucc.Their structures were elucidated by spectral methods, including 2D-NMR spectra.
2008, 19(2): 187-189
doi: 10.1016/j.cclet.2007.11.028
Abstract:
Two new diterpenes, 15-ethyl-18-methyl pinifolate (1) and 18-hydroxy-labda-8(17), 13E-dien-15-acetate (2), were isolated from the needles of Pinus sylvestris.Their structures were elucidated by spectroscopic methods, including 2D-NMR spectra.Compound 1 exhibited the significant eytotoxic activity against the human carcinoma cell lines Hela, SK-N-SH and BEL-7402 in vitro.
Two new diterpenes, 15-ethyl-18-methyl pinifolate (1) and 18-hydroxy-labda-8(17), 13E-dien-15-acetate (2), were isolated from the needles of Pinus sylvestris.Their structures were elucidated by spectroscopic methods, including 2D-NMR spectra.Compound 1 exhibited the significant eytotoxic activity against the human carcinoma cell lines Hela, SK-N-SH and BEL-7402 in vitro.
2008, 19(2): 190-192
doi: 10.1016/j.cclet.2007.11.029
Abstract:
A new triterpenoid saponin, 3-O-[(6'-butyryl)-β-D-glucopyranosyl]-28-O-[α-L-thamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl] oleanolic acid, as well as three known triterpenoid saponins were isolated from the rhizomes of Anemone flaccida.Their structures were elucidated by spectroscopic methods.These compounds showed significant antitumor activities.
A new triterpenoid saponin, 3-O-[(6'-butyryl)-β-D-glucopyranosyl]-28-O-[α-L-thamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl] oleanolic acid, as well as three known triterpenoid saponins were isolated from the rhizomes of Anemone flaccida.Their structures were elucidated by spectroscopic methods.These compounds showed significant antitumor activities.
2008, 19(2): 193-195
doi: 10.1016/j.cclet.2007.12.010
Abstract:
A new cyclopeptide as well as a known cyclopeptide were isolated from the whole plants of Dianthus caryophyllus.Their structures were elucidated as cyclo (-Thr-Gly-Pro-Tyr-Pbe-)(1) and cyclo (-Ala-Gly-Ser-IIe-Phe-Phe-)(2) by means of chemical and spectroscopic methods including MS, ID and 2D NMR techniques.
A new cyclopeptide as well as a known cyclopeptide were isolated from the whole plants of Dianthus caryophyllus.Their structures were elucidated as cyclo (-Thr-Gly-Pro-Tyr-Pbe-)(1) and cyclo (-Ala-Gly-Ser-IIe-Phe-Phe-)(2) by means of chemical and spectroscopic methods including MS, ID and 2D NMR techniques.
2008, 19(2): 196-198
doi: 10.1016/j.cclet.2007.12.011
Abstract:
A new benzofuranolignan austrafuran A (1) and a new flavonol derivative 5, 7, 2', 4'-tetrahydroxy-3-methoxyflavone (2) were isolated from the stem of Morus australis.Their structures were determined on the basis of spectroscopic evidences.
A new benzofuranolignan austrafuran A (1) and a new flavonol derivative 5, 7, 2', 4'-tetrahydroxy-3-methoxyflavone (2) were isolated from the stem of Morus australis.Their structures were determined on the basis of spectroscopic evidences.
2008, 19(2): 199-202
doi: 10.1016/j.cclet.2007.12.003
Abstract:
A visible rectification effect on the current-voltage curves of metal/porous silicon/p-silicon has been observed by currentsensing atomic force microscopy.The current-voltage curves of porous silicon membranes with different porosities, prepared through variation of etching current density for a constant time, indicate that a higher porosity results in a higher resistance and thus a lower rectification, until the current reaches a threshold at a porosity > 55%.We propose that the conductance mode in the porous silicon membrane with porosities > 55% is mainly a hopping mechanism between nano-crystallites and an inverse static electric field between the porous silicon and p-Si interface blocks the electron injection from porous silicon to p-Si, but with porosities ≤ 55%, electron flows through a direct continuous channel between nano-crystallites.
A visible rectification effect on the current-voltage curves of metal/porous silicon/p-silicon has been observed by currentsensing atomic force microscopy.The current-voltage curves of porous silicon membranes with different porosities, prepared through variation of etching current density for a constant time, indicate that a higher porosity results in a higher resistance and thus a lower rectification, until the current reaches a threshold at a porosity > 55%.We propose that the conductance mode in the porous silicon membrane with porosities > 55% is mainly a hopping mechanism between nano-crystallites and an inverse static electric field between the porous silicon and p-Si interface blocks the electron injection from porous silicon to p-Si, but with porosities ≤ 55%, electron flows through a direct continuous channel between nano-crystallites.
2008, 19(2): 203-206
doi: 10.1016/j.cclet.2007.10.050
Abstract:
A high sensitive flow-injection chemiluminescence (FI-CL) method for the determination of tryptephan has been developed.The method is based on the chemiluminescence reaction of galangin-potassium perrnanganate-tryptophan in polyphosphoric acid (PPA) media.Under the optimized conditions, tryptophan was determined in the range 0.05-10 μg/mL with the detection limit (3σ) of 5.0×10-3 μg/mL.The relative standard deviation (RSD) was 1.0% for 11 replicate determinations of 1.0 μg/mL tryptophan.Three synthetic samples were determined selectively with recoveries in the range from 99.6% to 102.0% in the presence of other amino acids.
A high sensitive flow-injection chemiluminescence (FI-CL) method for the determination of tryptephan has been developed.The method is based on the chemiluminescence reaction of galangin-potassium perrnanganate-tryptophan in polyphosphoric acid (PPA) media.Under the optimized conditions, tryptophan was determined in the range 0.05-10 μg/mL with the detection limit (3σ) of 5.0×10-3 μg/mL.The relative standard deviation (RSD) was 1.0% for 11 replicate determinations of 1.0 μg/mL tryptophan.Three synthetic samples were determined selectively with recoveries in the range from 99.6% to 102.0% in the presence of other amino acids.
2008, 19(2): 207-210
doi: 10.1016/j.cclet.2007.12.006
Abstract:
For the purpose of developing flexible organic photovoltaic devices, we have fabricated two flexible devices using 5-formyl-2, 2':5', 2":5", 2"'-quaterthiophene (4T-CHO), 5-formyl-2, 2':5', 2":5", 2'":5"', 2"''-quinquethiophene (5T-CHO) and 3, 4, 9, 10-peryle-netertracarboxylic dianhydride (PTCDA).The PET-ITO/4T-CHO/PTCDA/AI device has an open circuit voltage (V∝) of 1.56 V, photoelectric conversion efficiency of 0.77%.The PET-ITO/ST-CHO/PTCDA/AI device has a V∝ of 1.70 V, photoelectric conversion efficiency of 0.84%.The two flexible devices have high V∝(1.56 and 1.70 V).It is possible that intermolecular hydrogen bonding between-CHO group of nT-CHO and carboxylic dianhydride of PTCDA contributes to enhancing the efficiency by promoting interfacial electron transfer and eliminating the subconducting band trap sites.
For the purpose of developing flexible organic photovoltaic devices, we have fabricated two flexible devices using 5-formyl-2, 2':5', 2":5", 2"'-quaterthiophene (4T-CHO), 5-formyl-2, 2':5', 2":5", 2'":5"', 2"''-quinquethiophene (5T-CHO) and 3, 4, 9, 10-peryle-netertracarboxylic dianhydride (PTCDA).The PET-ITO/4T-CHO/PTCDA/AI device has an open circuit voltage (V∝) of 1.56 V, photoelectric conversion efficiency of 0.77%.The PET-ITO/ST-CHO/PTCDA/AI device has a V∝ of 1.70 V, photoelectric conversion efficiency of 0.84%.The two flexible devices have high V∝(1.56 and 1.70 V).It is possible that intermolecular hydrogen bonding between-CHO group of nT-CHO and carboxylic dianhydride of PTCDA contributes to enhancing the efficiency by promoting interfacial electron transfer and eliminating the subconducting band trap sites.
2008, 19(2): 211-214
doi: 10.1016/j.cclet.2007.10.053
Abstract:
A new strategy using an amperometric biosensor with Escherichia coli(E.coli) that provides a rapid toxicity determination of chemical compounds is described.The CellSense biosensor system comprises a biological component immobilized in intimate contact with a transducer which converts the biochemical signal into a quantifiable electrical signal.Toxicity assessment of heavy metals using E.coli biosensors could be finished within 30 min and the 50% effective concentrations (EC50) values of four heavy metals were determined.The results shows that inhibitory effects of four heavy metals to E.coli can be ranked in a decreasing order of Hg2+ > Cu2+ > Zn2+ > Ni2+, which accords to the results of conventional bacterial counting method.The toxicity test of organic compounds by using CellSense biosensor was also demonstrated.The CellSense biosensor with E.coli shows a good, reproducible behavior and can be used for reproducible measurements.
A new strategy using an amperometric biosensor with Escherichia coli(E.coli) that provides a rapid toxicity determination of chemical compounds is described.The CellSense biosensor system comprises a biological component immobilized in intimate contact with a transducer which converts the biochemical signal into a quantifiable electrical signal.Toxicity assessment of heavy metals using E.coli biosensors could be finished within 30 min and the 50% effective concentrations (EC50) values of four heavy metals were determined.The results shows that inhibitory effects of four heavy metals to E.coli can be ranked in a decreasing order of Hg2+ > Cu2+ > Zn2+ > Ni2+, which accords to the results of conventional bacterial counting method.The toxicity test of organic compounds by using CellSense biosensor was also demonstrated.The CellSense biosensor with E.coli shows a good, reproducible behavior and can be used for reproducible measurements.
2008, 19(2): 215-218
doi: 10.1016/j.cclet.2007.11.008
Abstract:
Water-soluble CdSe/ZnS quantum dots (QDs) were prepared via a simple sonochemical procedure using β-cyclodextrin (CD) as surface coating agent.The QDs displayed a sensitive emission enhancement for anthracene over other related polycyclic aromatic hydrocarbons, and the detection limit was around 1.6×10-8 mol/L.
Water-soluble CdSe/ZnS quantum dots (QDs) were prepared via a simple sonochemical procedure using β-cyclodextrin (CD) as surface coating agent.The QDs displayed a sensitive emission enhancement for anthracene over other related polycyclic aromatic hydrocarbons, and the detection limit was around 1.6×10-8 mol/L.
Determination of petroleum sulfonates in crude oil by column-switching anion-exchange chromatography
2008, 19(2): 219-222
doi: 10.1016/j.cclet.2007.12.015
Abstract:
A column-switching anion-exchange chromatography method was described for the separation and determination of petroleum monosulfonates (PMS) and petroleum disulfonates (PDS) in crude oil that was simply diluted with the dichloromethane/methanol (60/40).The high performance liquid chromatography (HPLC) system consisted of a clean-up column and an analytical column, which were connected with two six-port switching valves.Detection of petroleum sulfonates was available and repeatable.This method has been successfully applied to determine PMS and PDS in crude oil samples from Shengli oil field.
A column-switching anion-exchange chromatography method was described for the separation and determination of petroleum monosulfonates (PMS) and petroleum disulfonates (PDS) in crude oil that was simply diluted with the dichloromethane/methanol (60/40).The high performance liquid chromatography (HPLC) system consisted of a clean-up column and an analytical column, which were connected with two six-port switching valves.Detection of petroleum sulfonates was available and repeatable.This method has been successfully applied to determine PMS and PDS in crude oil samples from Shengli oil field.
2008, 19(2): 223-226
doi: 10.1016/j.cclet.2007.12.005
Abstract:
Nanobelts, flower-like and rhizoid-like nanostructures of pure polyaniline (PANI) doped with sulfuric acid or hydrochloric acid were prepared via electrospinning by using a coagulation bath as the collector after optimizing the fabrication parameters.The morphologies of these nanostructures were characterized by scanning electron microscope (SEM).The possible formation mechanisms were discussed.
Nanobelts, flower-like and rhizoid-like nanostructures of pure polyaniline (PANI) doped with sulfuric acid or hydrochloric acid were prepared via electrospinning by using a coagulation bath as the collector after optimizing the fabrication parameters.The morphologies of these nanostructures were characterized by scanning electron microscope (SEM).The possible formation mechanisms were discussed.
2008, 19(2): 227-229
doi: 10.1016/j.cclet.2007.11.005
Abstract:
A novel series of poly (aryl ether sulfone ketone) s (PPESKs) containing phthalazinone and biphenyl moieties were prepared by two-step nucleophilic polycondensation reaction.The (M)w values of these copolymers were between 38, 330 and 67, 900.The glass transition temperatures (Tg) and 5% decomposition temperatures were ranged in 253-269℃ and 488-500℃, respectively, The structures of these copolymers were confirmed by FT-IR and 1H NMR.Moreover, all the resultant copolymers were amorphous determined by wide angle X-ray diffraction (WAXD).
A novel series of poly (aryl ether sulfone ketone) s (PPESKs) containing phthalazinone and biphenyl moieties were prepared by two-step nucleophilic polycondensation reaction.The (M)w values of these copolymers were between 38, 330 and 67, 900.The glass transition temperatures (Tg) and 5% decomposition temperatures were ranged in 253-269℃ and 488-500℃, respectively, The structures of these copolymers were confirmed by FT-IR and 1H NMR.Moreover, all the resultant copolymers were amorphous determined by wide angle X-ray diffraction (WAXD).
2008, 19(2): 230-232
doi: 10.1016/j.cclet.2007.11.006
Abstract:
Block copolymers with different backbone compositions have been prepared by the condensation of dimethylamino terminated poly (dimethylsiloxane)(PDMS) and hydroquinone terminated poly (phthalazinone ether nitrile)(PPEN) in the presence of chlorobenzene/N-methyl pyrrolidone (NMP) as solvents.The products were characterized by FTIR, 1H NMR and gel permeation chromatography.Differential scanning calorimetry analysis indicated that the block copolymers showed separated microphase.
Block copolymers with different backbone compositions have been prepared by the condensation of dimethylamino terminated poly (dimethylsiloxane)(PDMS) and hydroquinone terminated poly (phthalazinone ether nitrile)(PPEN) in the presence of chlorobenzene/N-methyl pyrrolidone (NMP) as solvents.The products were characterized by FTIR, 1H NMR and gel permeation chromatography.Differential scanning calorimetry analysis indicated that the block copolymers showed separated microphase.
2008, 19(2): 233-236
doi: 10.1016/j.cclet.2007.10.045
Abstract:
A new functional glycomonomer was obtained from modified glucosamine.Hemoglobin-imprinted polymer gel was prepared with allyl-bromide modified glucosamine as functional monomer, poly (ethylene-glycol) diaorylate (PEGDA) as cross-linker and ammonium persulfate[(NH4)2S2O8]/sodium hydrogen sulfite (NaHSO3) as initiators in a phosphate buffer.The adsorption capacity and selective adsorption of the molecular imprinting polymer (MIP) were also discussed.
A new functional glycomonomer was obtained from modified glucosamine.Hemoglobin-imprinted polymer gel was prepared with allyl-bromide modified glucosamine as functional monomer, poly (ethylene-glycol) diaorylate (PEGDA) as cross-linker and ammonium persulfate[(NH4)2S2O8]/sodium hydrogen sulfite (NaHSO3) as initiators in a phosphate buffer.The adsorption capacity and selective adsorption of the molecular imprinting polymer (MIP) were also discussed.
2008, 19(2): 237-240
doi: 10.1016/j.cclet.2007.11.024
Abstract:
H-type amphiphilic liquid crystalline block copolymers containing azobenzene were synthesized by atom transfer radical polymerization (ATRP).Macroinitiators prepared by the esteriflcation between poly (ethylene oxide)(PEG) and 2, 2-dichloroacetyl chloride were utilized to initiate the polymerization of 6-[4-(4-ethoxyphenylazo) phenoxy]hexyl methacrylate (M6C).The resulting macroinitiators and block copolymers were characterized by 1H NMR, gel permeation chromatography (GPC).Polarizing optical microscopy (POM) and differential scanning calorimetry (DSC) preliminarily revealed the liquid crystalline property of these block copolymers.This series of liquid crystalline block copolymers are promising in some areas, such as optical data storage, optical switch, and molecular devices.
H-type amphiphilic liquid crystalline block copolymers containing azobenzene were synthesized by atom transfer radical polymerization (ATRP).Macroinitiators prepared by the esteriflcation between poly (ethylene oxide)(PEG) and 2, 2-dichloroacetyl chloride were utilized to initiate the polymerization of 6-[4-(4-ethoxyphenylazo) phenoxy]hexyl methacrylate (M6C).The resulting macroinitiators and block copolymers were characterized by 1H NMR, gel permeation chromatography (GPC).Polarizing optical microscopy (POM) and differential scanning calorimetry (DSC) preliminarily revealed the liquid crystalline property of these block copolymers.This series of liquid crystalline block copolymers are promising in some areas, such as optical data storage, optical switch, and molecular devices.
2008, 19(2): 241-244
doi: 10.1016/j.cclet.2007.12.012
Abstract:
An improved method for preparing melamine cyanurate (MCA) based flame retardant polyamide 6 (FRPA6) materials has been proposed.This processing method, i.e., improved in situ polymerization, was used to synthesize flame retardant PA6.In situ formed MCA nanoparticles were supposed to be linked to PA6 chains in the ε-caprolactam hydrolytic polymerization system to obtain startype polymers for the first time.Through TEM photographs, it can be found that the in situ formed MCA nanoparticles with diametric size of less than 50 nm, are nanoscaled, highly uniformly dispersed in the PA6 matrix.Synthesized flame retardant PA6 have good fire performance which can achieve UL-94 V-0 rating at 1.6 mm thickness with the presence of 7.34 wt.% MCA in the matrix.
An improved method for preparing melamine cyanurate (MCA) based flame retardant polyamide 6 (FRPA6) materials has been proposed.This processing method, i.e., improved in situ polymerization, was used to synthesize flame retardant PA6.In situ formed MCA nanoparticles were supposed to be linked to PA6 chains in the ε-caprolactam hydrolytic polymerization system to obtain startype polymers for the first time.Through TEM photographs, it can be found that the in situ formed MCA nanoparticles with diametric size of less than 50 nm, are nanoscaled, highly uniformly dispersed in the PA6 matrix.Synthesized flame retardant PA6 have good fire performance which can achieve UL-94 V-0 rating at 1.6 mm thickness with the presence of 7.34 wt.% MCA in the matrix.
2008, 19(2): 245-248
doi: 10.1016/j.cclet.2007.11.015
Abstract:
A novel vanadium oxide catalyst supported on active carbon was prepared by an incipient wetness impregnation method, and the precursor was obtained from oxalic acid aqueous solutions of NH4VO3.The catalyst was applied liquid phase oxidation of glyoxal to glyoxylic acid.It was found that V2O5/C catalyst exhibited obvious activity for glyoxal oxidation.Glyoxylic acid could be obtained without pH regulation during the reaction.By using this catalyst, the conversion of glyoxal and the yield of glyoxalic acid were 29.2% and 13.6%, respectively at 313 K and oxygen flow 0.1 L/min after reaction for 10h.
A novel vanadium oxide catalyst supported on active carbon was prepared by an incipient wetness impregnation method, and the precursor was obtained from oxalic acid aqueous solutions of NH4VO3.The catalyst was applied liquid phase oxidation of glyoxal to glyoxylic acid.It was found that V2O5/C catalyst exhibited obvious activity for glyoxal oxidation.Glyoxylic acid could be obtained without pH regulation during the reaction.By using this catalyst, the conversion of glyoxal and the yield of glyoxalic acid were 29.2% and 13.6%, respectively at 313 K and oxygen flow 0.1 L/min after reaction for 10h.
2008, 19(2): 249-252
doi: 10.1016/j.cclet.2007.12.007
Abstract:
Critical temperatures and pressures of nominal reacting mixture in synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide (quaternary mixture of carbon dioxide+methanol+water+DMC) were measured using a high-pressure view cell.The results suggested that the critical properties of the reacting mixture depended on the reaction extent as well as its initial composition (initial ratio of carbon dioxide to methanol).Such information is essential for determining the reaction conditions when one intends to carry out the synthesis of DMC with CO2 and methanol under supercritical conditions.
Critical temperatures and pressures of nominal reacting mixture in synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide (quaternary mixture of carbon dioxide+methanol+water+DMC) were measured using a high-pressure view cell.The results suggested that the critical properties of the reacting mixture depended on the reaction extent as well as its initial composition (initial ratio of carbon dioxide to methanol).Such information is essential for determining the reaction conditions when one intends to carry out the synthesis of DMC with CO2 and methanol under supercritical conditions.
