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2007 Volume 18 Issue 6
2007, 18(6): 625-628
doi: 10.1016/j.cclet.2007.04.014
Abstract:
Some 1, 3-dicarbonyl compounds (such as pentane-2, 4-dione and 3-oxo-N-phenylbutanamide) were found to constitute highly efficient, yet low-priced and phosphine-free ligands for the Pd-catalyzed Heck and Suzuki reactions of aryl bromides and iodides with very high turnover numbers (ca.103-104).
Some 1, 3-dicarbonyl compounds (such as pentane-2, 4-dione and 3-oxo-N-phenylbutanamide) were found to constitute highly efficient, yet low-priced and phosphine-free ligands for the Pd-catalyzed Heck and Suzuki reactions of aryl bromides and iodides with very high turnover numbers (ca.103-104).
2007, 18(6): 629-632
doi: 10.1016/j.cclet.2007.04.001
Abstract:
Reductive cleavage of the N-O bond of isoxazolidine ring with catalytic hydrogenation over Raney nickel was described.Bicyclic isoxazolidines could be effectively converted into the corresponding 1, 3-amino-alcohol possessing a sultone or sultam moiety with high conversion and yield when the hydrogenation was catalyzed by freshly prepared Raney nickel under a pressure of 40 psi in the presence of triethylamine.
Reductive cleavage of the N-O bond of isoxazolidine ring with catalytic hydrogenation over Raney nickel was described.Bicyclic isoxazolidines could be effectively converted into the corresponding 1, 3-amino-alcohol possessing a sultone or sultam moiety with high conversion and yield when the hydrogenation was catalyzed by freshly prepared Raney nickel under a pressure of 40 psi in the presence of triethylamine.
2007, 18(6): 633-635
doi: 10.1016/j.cclet.2007.04.012
Abstract:
Starting from the hydroxylamine (dimethyl amino ethanol, triethanolamine) and 1, 3-propane sultone, a series of hydroxyl and sulfonyl dual-functionalized zwitterionic salts and corresponding acidic room temperature ionic liquids have been synthesized.The hydroxyl groups of the synthesized substances were confirmed by the 1H NMR measurement.These zwitterionic salts and ionic liquids may be used for synthesizing other functionalized ionic liquids or ionic liquid-polymer (polyelectrolyte).
Starting from the hydroxylamine (dimethyl amino ethanol, triethanolamine) and 1, 3-propane sultone, a series of hydroxyl and sulfonyl dual-functionalized zwitterionic salts and corresponding acidic room temperature ionic liquids have been synthesized.The hydroxyl groups of the synthesized substances were confirmed by the 1H NMR measurement.These zwitterionic salts and ionic liquids may be used for synthesizing other functionalized ionic liquids or ionic liquid-polymer (polyelectrolyte).
2007, 18(6): 636-638
doi: 10.1016/j.cclet.2007.04.015
Abstract:
2H-3, 1-Pyrazolo[3, 4-e]oxazines (5a-c) and tacrine analogies (6a-c) were designed and prepared using 5-amino-4-cyanopyrazole (7) and cycloketones (2a-c) as reactants.The study demonstrated that the new conversion existed in the Friedländer reaction of o-aminocyanopyrazole with cycloketones.
2H-3, 1-Pyrazolo[3, 4-e]oxazines (5a-c) and tacrine analogies (6a-c) were designed and prepared using 5-amino-4-cyanopyrazole (7) and cycloketones (2a-c) as reactants.The study demonstrated that the new conversion existed in the Friedländer reaction of o-aminocyanopyrazole with cycloketones.
2007, 18(6): 639-642
doi: 10.1016/j.cclet.2007.04.031
Abstract:
For searching a better 4-aminosalicylic acid derivative with higher activity and less side effects against the inflammatory bowel disease, 4-aminosalicylic acid (4-ASA) was protected by benzyloxycarbonyl and acetyl, respectively.The resultant was hydrogenized to remove protective group of amino group, then the product was reacted with NaNO2 to give diazonium salt, which was conjugated with salicylic acid, hydroxybenzene, N-salicyloyl glycine acid to get azo derivatives of 4-ASA.The azo derivatives were hydrolyzed under the alkaline condition to get the target products.All compounds were characterized by FT-IR, 1H NMR, 13C NMR spectra in details.New derivatives of 4-ASA were characterized.The synthetic route was reasonable and feasible.
For searching a better 4-aminosalicylic acid derivative with higher activity and less side effects against the inflammatory bowel disease, 4-aminosalicylic acid (4-ASA) was protected by benzyloxycarbonyl and acetyl, respectively.The resultant was hydrogenized to remove protective group of amino group, then the product was reacted with NaNO2 to give diazonium salt, which was conjugated with salicylic acid, hydroxybenzene, N-salicyloyl glycine acid to get azo derivatives of 4-ASA.The azo derivatives were hydrolyzed under the alkaline condition to get the target products.All compounds were characterized by FT-IR, 1H NMR, 13C NMR spectra in details.New derivatives of 4-ASA were characterized.The synthetic route was reasonable and feasible.
2007, 18(6): 643-646
doi: 10.1016/j.cclet.2007.04.003
Abstract:
Microwave-assisted Kornblum oxidation is proved to be an effective way to obtain aldehyde and ketones from their corresponding chlorides.Under microwave irradiation, not only the reaction time was greatly decreased, due to avoiding the by-product, the yield was increased.It is noteworthy that the scope of the method was broadly expanded.
Microwave-assisted Kornblum oxidation is proved to be an effective way to obtain aldehyde and ketones from their corresponding chlorides.Under microwave irradiation, not only the reaction time was greatly decreased, due to avoiding the by-product, the yield was increased.It is noteworthy that the scope of the method was broadly expanded.
2007, 18(6): 647-650
doi: 10.1016/j.cclet.2007.04.002
Abstract:
An efficient synthesis of 3, 4-dihydropyrirnidin-2(1H)-one derivatives using formic acid as catalyst, from aldehydes, β-ketoester and urea (thiourea) without solvent under the irradiation of microwave is described.Compared with the classical Biginelli reaction, this new method has the advantage of good yields (77-94% for aromatic aldehydes) and short reaction time (3-8 min).
An efficient synthesis of 3, 4-dihydropyrirnidin-2(1H)-one derivatives using formic acid as catalyst, from aldehydes, β-ketoester and urea (thiourea) without solvent under the irradiation of microwave is described.Compared with the classical Biginelli reaction, this new method has the advantage of good yields (77-94% for aromatic aldehydes) and short reaction time (3-8 min).
2007, 18(6): 651-652
doi: 10.1016/j.cclet.2007.04.032
Abstract:
Trolline, a new bioactive alkaloid was isolated in 2004.We reported herein the first total synthesis of (±)-trolline, in two steps and 18.0% overall yield.
Trolline, a new bioactive alkaloid was isolated in 2004.We reported herein the first total synthesis of (±)-trolline, in two steps and 18.0% overall yield.
2007, 18(6): 653-655
doi: 10.1016/j.cclet.2007.04.040
Abstract:
Optically active 3-butylphtalide of high enantiomeric excesses (up to 93% e.e.) was synthesized from the reduction of o-pentanoylbenzoic ester with borane using B-methyloxyoxazaborolidine (1b) as the chiral catalyst.
Optically active 3-butylphtalide of high enantiomeric excesses (up to 93% e.e.) was synthesized from the reduction of o-pentanoylbenzoic ester with borane using B-methyloxyoxazaborolidine (1b) as the chiral catalyst.
2007, 18(6): 656-658
doi: 10.1016/j.cclet.2007.04.036
Abstract:
2-Substituted-2, 3-dihydro-4(1H)-quinazolinones Were obtained in high yields by condensation of anthranilamide with aryl, alkyl or heteroaryl aldehydes or ketones in the refluxing 2, 2, 2-trifluoroethanol without any catalyst.
2-Substituted-2, 3-dihydro-4(1H)-quinazolinones Were obtained in high yields by condensation of anthranilamide with aryl, alkyl or heteroaryl aldehydes or ketones in the refluxing 2, 2, 2-trifluoroethanol without any catalyst.
2007, 18(6): 659-662
doi: 10.1016/j.cclet.2007.04.010
Abstract:
Through simplifying the complicated skeleton of the natural product gambogic acid, two series derivatives of chromone and xanthone were synthesized and examined for their antitumor activities against several cancer cells in vitro by MTT method.The results showed that appropriate introduction of prenyl group to the small molecular compounds could elevate their antitumor activities.The structure-activities relationship of synthesized compounds certified that the bridgecore in gambogic acid was very important for keeping its antitumor activities.
Through simplifying the complicated skeleton of the natural product gambogic acid, two series derivatives of chromone and xanthone were synthesized and examined for their antitumor activities against several cancer cells in vitro by MTT method.The results showed that appropriate introduction of prenyl group to the small molecular compounds could elevate their antitumor activities.The structure-activities relationship of synthesized compounds certified that the bridgecore in gambogic acid was very important for keeping its antitumor activities.
2007, 18(6): 663-666
doi: 10.1016/j.cclet.2007.04.025
Abstract:
Based on the active site of Candida albicans lanosterol 14α-demethylase (CACYP51), novel triazole compounds structurally different from the current triazole drugs were designed and synthesized.In vitro antifungal activities showed that compounds 10, 11, 16 and 20 exhibited strong activities.In addition, compounds 10, 11 and 16 also displayed certain activities against fluconazole-resistant fungi.
Based on the active site of Candida albicans lanosterol 14α-demethylase (CACYP51), novel triazole compounds structurally different from the current triazole drugs were designed and synthesized.In vitro antifungal activities showed that compounds 10, 11, 16 and 20 exhibited strong activities.In addition, compounds 10, 11 and 16 also displayed certain activities against fluconazole-resistant fungi.
2007, 18(6): 667-669
doi: 10.1016/j.cclet.2007.04.007
Abstract:
When rhodamine-based fluorescent probe dyes are used to track target molecules they always perturb the behavior of target molecules because of steric hindrance effect.In order to minimize potential steric problems, a kind of rhodamine-based fluorescent probe dye with spacer linker arm was designed and synthesized and its application in immunofluorescence histochemistry was investigated.
When rhodamine-based fluorescent probe dyes are used to track target molecules they always perturb the behavior of target molecules because of steric hindrance effect.In order to minimize potential steric problems, a kind of rhodamine-based fluorescent probe dye with spacer linker arm was designed and synthesized and its application in immunofluorescence histochemistry was investigated.
2007, 18(6): 670-672
doi: 10.1016/j.cclet.2007.04.019
Abstract:
Twenty-three 1-(1H-1, 2, 4-triazole-1-yl)-2-(2, 4-difluorophenyl)-3-(N-cycloproyl-N-substituted-amino)-2-propanols were designed and synthesized on the basis of the active site of lanosterol 14α-demethylase.In vitro antifungal activities showed that some of the title compounds had higher antifungal activity and broader antifungal spectrum than fluconazole.
Twenty-three 1-(1H-1, 2, 4-triazole-1-yl)-2-(2, 4-difluorophenyl)-3-(N-cycloproyl-N-substituted-amino)-2-propanols were designed and synthesized on the basis of the active site of lanosterol 14α-demethylase.In vitro antifungal activities showed that some of the title compounds had higher antifungal activity and broader antifungal spectrum than fluconazole.
2007, 18(6): 673-676
doi: 10.1016/j.cclet.2007.03.005
Abstract:
Endo-dicyclopentadiene was isomerized to exo-isomer by thermal treatment at evaluated temperature and pressure.The reaction temperature and pressure are key factors for this novel isomerization.This result may have great potential for practical application.
Endo-dicyclopentadiene was isomerized to exo-isomer by thermal treatment at evaluated temperature and pressure.The reaction temperature and pressure are key factors for this novel isomerization.This result may have great potential for practical application.
2007, 18(6): 677-680
doi: 10.1016/j.cclet.2007.04.034
Abstract:
By using acetonitrile as the sole nitrogen source, a microbial strain with high nitrilase activity, named as Alcaligenes sp.ECU0401, was newly isolated from soil, which could enantioselectively transform racemic mandelonitrile into (R)-(-)-mandelic acid, with an enantiomeric excess of >99.9%.
By using acetonitrile as the sole nitrogen source, a microbial strain with high nitrilase activity, named as Alcaligenes sp.ECU0401, was newly isolated from soil, which could enantioselectively transform racemic mandelonitrile into (R)-(-)-mandelic acid, with an enantiomeric excess of >99.9%.
2007, 18(6): 681-684
doi: 10.1016/j.cclet.2007.04.022
Abstract:
Baker's yeast mediated reduction of acenaphthenequinone within 4-10 h afforded mono-hydroxyacenaphthenone mainly with low enantioselectivity, the substrate and mono-hydroxyacenaphthenone product almost converted to dihydroxyacenaphthene after 48 h.By control of the reaction time and in the presence of DMF as co-solvent, the reduction of 6-substituted acenaphthenequinones under vigorous agitation afforded the corresponding 2-hydroxyacenaphthenones in 24-84% yields with 10-93% ee.
Baker's yeast mediated reduction of acenaphthenequinone within 4-10 h afforded mono-hydroxyacenaphthenone mainly with low enantioselectivity, the substrate and mono-hydroxyacenaphthenone product almost converted to dihydroxyacenaphthene after 48 h.By control of the reaction time and in the presence of DMF as co-solvent, the reduction of 6-substituted acenaphthenequinones under vigorous agitation afforded the corresponding 2-hydroxyacenaphthenones in 24-84% yields with 10-93% ee.
2007, 18(6): 685-688
doi: 10.1016/j.cclet.2007.04.008
Abstract:
A novel K2O and La2O3 promoted nickel catalyst supported on α-Al2O3 was prepared by co-impregnation method, and it exhibited higher activity and 6-aminocapronitrile selectivity than Ni/α-Al2O3 during the hydrogenation of adiponitrile in the absence of ammonia, i.e., K2O and La2O3 improved the performance of the nickel-based catalyst.
A novel K2O and La2O3 promoted nickel catalyst supported on α-Al2O3 was prepared by co-impregnation method, and it exhibited higher activity and 6-aminocapronitrile selectivity than Ni/α-Al2O3 during the hydrogenation of adiponitrile in the absence of ammonia, i.e., K2O and La2O3 improved the performance of the nickel-based catalyst.
2007, 18(6): 689-693
doi: 10.1016/j.cclet.2007.04.020
Abstract:
The reaction of dichlorodiphenoxymethane (2) with orthio-functionlized benzoic acids 1a-c yielded the spiro derivatives of bezodioxinone 4a, benzoxazinone 4b and benzodioxepinone 4c.The same reaction with 1, 8-diaminonaphthalene afforded the spiro perimidine 6, while with 1, 1'-binaphthyl-2, 2'-diol gave the semi-cyclized derivative 2, 2-diphenoxydinaphthodioxepine 8.
The reaction of dichlorodiphenoxymethane (2) with orthio-functionlized benzoic acids 1a-c yielded the spiro derivatives of bezodioxinone 4a, benzoxazinone 4b and benzodioxepinone 4c.The same reaction with 1, 8-diaminonaphthalene afforded the spiro perimidine 6, while with 1, 1'-binaphthyl-2, 2'-diol gave the semi-cyclized derivative 2, 2-diphenoxydinaphthodioxepine 8.
2007, 18(6): 694-696
doi: 10.1016/j.cclet.2007.04.004
Abstract:
Two new isoflavonoids, 6-methoxy-5, 7, 8, 4'-tetrahydryoxyisoflavone (1) and 4'-methoxy -5, 6-dihydroxyisoflavone-7-O-β-D-glucopyranoside (2), were isolated from the rhizomes of Belamcanda chinensis (L.) DC.Their structures were elucidated by extensive spectroscopic evidence including 1D NMR, 2D NMR, MS and IR spectra.
Two new isoflavonoids, 6-methoxy-5, 7, 8, 4'-tetrahydryoxyisoflavone (1) and 4'-methoxy -5, 6-dihydroxyisoflavone-7-O-β-D-glucopyranoside (2), were isolated from the rhizomes of Belamcanda chinensis (L.) DC.Their structures were elucidated by extensive spectroscopic evidence including 1D NMR, 2D NMR, MS and IR spectra.
2007, 18(6): 697-699
doi: 10.1016/j.cclet.2007.04.013
Abstract:
Six indole alkaloids were isolated from the stems of Ervatamia yunnanensis.Among them, yunnanensine (Ⅰ) is new.The other five are known alkaloids, namely:19, 20-E-vallesamine (Ⅱ), 19s-heyneanine (Ⅲ), ibogaine (Ⅳ), ibogamine (Ⅴ), coronaridine (Ⅵ).The structural elucidation of the alkaloids was based on spectral means.
Six indole alkaloids were isolated from the stems of Ervatamia yunnanensis.Among them, yunnanensine (Ⅰ) is new.The other five are known alkaloids, namely:19, 20-E-vallesamine (Ⅱ), 19s-heyneanine (Ⅲ), ibogaine (Ⅳ), ibogamine (Ⅴ), coronaridine (Ⅵ).The structural elucidation of the alkaloids was based on spectral means.
2007, 18(6): 700-703
doi: 10.1016/j.cclet.2007.04.026
Abstract:
Three new lycoctonine-type C19-diterpenoid alkaloids, laxicymine 1, laxicymisine 2, and laxicyminine 3 have been isolated from the whole herb of Delphinium laxicymosum var. pilostachyum W.T.Wang.Their structures were established by spectra data.
Three new lycoctonine-type C19-diterpenoid alkaloids, laxicymine 1, laxicymisine 2, and laxicyminine 3 have been isolated from the whole herb of Delphinium laxicymosum var. pilostachyum W.T.Wang.Their structures were established by spectra data.
2007, 18(6): 704-707
doi: 10.1016/j.cclet.2007.04.028
Abstract:
A new franchetine-type C19-diterpenoid alkaloid 3-hydroxyfranchetine 1 and a new aconitine-type C19-diterpenoid alkaloid atropurpursine 2 have been isolated from the roots of Aconitum hemsleyanium var. atropurpureum.The structures of these new alkaloids were established on the basis of spectral data.
A new franchetine-type C19-diterpenoid alkaloid 3-hydroxyfranchetine 1 and a new aconitine-type C19-diterpenoid alkaloid atropurpursine 2 have been isolated from the roots of Aconitum hemsleyanium var. atropurpureum.The structures of these new alkaloids were established on the basis of spectral data.
2007, 18(6): 708-710
doi: 10.1016/j.cclet.2007.04.009
Abstract:
Two new triterpene fatty esters, 3β-tetradecanoyl moradiol 1 and 3β-dodecanoyl moradiol 2, were isolated from Scorzonera mongolica.Their structures were elucidated as 3β-tetradecanoyloxy-28-hydroxylolean-18-ene and 3β-dodecanoyl-28-hydroxyl-olean-18-ene on the basis of IR, MS, 1D NMR and extensive 2D NMR spectroscopic analyses.
Two new triterpene fatty esters, 3β-tetradecanoyl moradiol 1 and 3β-dodecanoyl moradiol 2, were isolated from Scorzonera mongolica.Their structures were elucidated as 3β-tetradecanoyloxy-28-hydroxylolean-18-ene and 3β-dodecanoyl-28-hydroxyl-olean-18-ene on the basis of IR, MS, 1D NMR and extensive 2D NMR spectroscopic analyses.
2007, 18(6): 711-713
doi: 10.1016/j.cclet.2007.04.017
Abstract:
In the H2SO4 medium and in the presence of dodecylbenzene sulfonic acid sodiumsalt (DBS), dimethyl yellow (R) could emit strong and stable solid substrate room temperature phosphorescence (RTF) on filter paper.And NaIO4 could oxidize R to cause the RTF quenching.Arsenic (V) could catalyze the reaction of NaIO4 oxidizing R, which caused the RTF sharply quenching.The reducing value of phosphorescence intensity (△Ip) for the system with DBS is 3.3 times higher than that without DBS.Moreover, the △Ip is proportional to the concentration of As (V).Based on the facts above, a new RTF quenching method for the determination of trace As (V) has been established.
In the H2SO4 medium and in the presence of dodecylbenzene sulfonic acid sodiumsalt (DBS), dimethyl yellow (R) could emit strong and stable solid substrate room temperature phosphorescence (RTF) on filter paper.And NaIO4 could oxidize R to cause the RTF quenching.Arsenic (V) could catalyze the reaction of NaIO4 oxidizing R, which caused the RTF sharply quenching.The reducing value of phosphorescence intensity (△Ip) for the system with DBS is 3.3 times higher than that without DBS.Moreover, the △Ip is proportional to the concentration of As (V).Based on the facts above, a new RTF quenching method for the determination of trace As (V) has been established.
2007, 18(6): 714-717
doi: 10.1016/j.cclet.2007.04.024
Abstract:
A procedure for the preconcentration of copper was described in this paper using multi-walled carbon nanotubes (MWCNTs) oxidized by potassium permanganate as the adsorbent for the enrichment of trace copper in water samples.Important parameters, such as the sample pH, the concentration and volume of eluent, sample flow rate and volume, and interference of coexisting ions, were investigated.The obtained results indicated that proposed method possessed an excellent analytical performance.The linear range, the detection limit, and precison (RSD) were 1-100 ng/mL (R2=0.9993), 0.32 ng/mL and 2.88%, respectively.The results showed that copper could be adsorbed quantitatively on the pretreated MWCNTs with potassium permanganate, and proposed method was very useful in the monitoring of copper in the environment.
A procedure for the preconcentration of copper was described in this paper using multi-walled carbon nanotubes (MWCNTs) oxidized by potassium permanganate as the adsorbent for the enrichment of trace copper in water samples.Important parameters, such as the sample pH, the concentration and volume of eluent, sample flow rate and volume, and interference of coexisting ions, were investigated.The obtained results indicated that proposed method possessed an excellent analytical performance.The linear range, the detection limit, and precison (RSD) were 1-100 ng/mL (R2=0.9993), 0.32 ng/mL and 2.88%, respectively.The results showed that copper could be adsorbed quantitatively on the pretreated MWCNTs with potassium permanganate, and proposed method was very useful in the monitoring of copper in the environment.
2007, 18(6): 718-721
doi: 10.1016/j.cclet.2007.04.027
Abstract:
A novel sample preparation method of matrix-assisted laser desorption/ionization mass spectrometry for polystyrene was reported.Compared to the conventional dried-droplet method, the efficiency of ionization and signal intensity of mass spectra were improved.The mechanism was also analyzed.
A novel sample preparation method of matrix-assisted laser desorption/ionization mass spectrometry for polystyrene was reported.Compared to the conventional dried-droplet method, the efficiency of ionization and signal intensity of mass spectra were improved.The mechanism was also analyzed.
2007, 18(6): 722-725
doi: 10.1016/j.cclet.2007.04.023
Abstract:
To study the possible anticancer mechanisms of chelerythrine (CHE), and its interactions with cytidine were investigated by UV-vis spectrophotometric and spectrofluorimetric measurements and by thermodynamic calculations.The binding of CHE to cytidine could be characterized by the hypochromic and bathochromic effects in the absorption bands, and the quenching of fluorescence intensity.The spectral data were fit by linear analysis, yielding a binding constant of 2.49×104 L mol-1at 25℃ of CHE and cytidine, and a van't Hoff enthalpy of -20.02 kJ/mol for the exothermic interaction in the standard state.In addition, with △rGMΘ=-25.09 kJ/mol and △rSmΘ=17.01 J/molK, the interactions should be entropy-driven.
To study the possible anticancer mechanisms of chelerythrine (CHE), and its interactions with cytidine were investigated by UV-vis spectrophotometric and spectrofluorimetric measurements and by thermodynamic calculations.The binding of CHE to cytidine could be characterized by the hypochromic and bathochromic effects in the absorption bands, and the quenching of fluorescence intensity.The spectral data were fit by linear analysis, yielding a binding constant of 2.49×104 L mol-1at 25℃ of CHE and cytidine, and a van't Hoff enthalpy of -20.02 kJ/mol for the exothermic interaction in the standard state.In addition, with △rGMΘ=-25.09 kJ/mol and △rSmΘ=17.01 J/molK, the interactions should be entropy-driven.
2007, 18(6): 726-729
doi: 10.1016/j.cclet.2007.04.033
Abstract:
The interaction between clarithromycin (CAM) and bovine serum albumin (BSA) was investigated using linear-sweep voltammetry in pH 7.4 phosphate buffer solution where CAM caused two irreversible reduction waves P2 and P3 on mercury electrode.The study showed that the formation constant and formation ratio for the interaction between CAM and BSA were 1.51×1012 and 3:1 for P2, 4.53×105 and 1:1 for P3, respectively.The ion strength enhanced the hydrophobic interaction between CAM and BSA.
The interaction between clarithromycin (CAM) and bovine serum albumin (BSA) was investigated using linear-sweep voltammetry in pH 7.4 phosphate buffer solution where CAM caused two irreversible reduction waves P2 and P3 on mercury electrode.The study showed that the formation constant and formation ratio for the interaction between CAM and BSA were 1.51×1012 and 3:1 for P2, 4.53×105 and 1:1 for P3, respectively.The ion strength enhanced the hydrophobic interaction between CAM and BSA.
2007, 18(6): 730-733
doi: 10.1016/j.cclet.2007.04.030
Abstract:
A new method for the determination of aniline in environmental water based on oscillopolarographic titration was presented in this paper.Several factors including the kind, concentration, and volume of acid, the dosage of potassium bromide, the temperature and concentration of concomitant substances were investigated in detail.The experimental results indicated that this method was simple, rapid, and sensitive.The linear range was 8.367×10-4 to 2.789×10-2 mol L-1, the relative standard deviation (R.S.D.) was lower than 0.96%, and the spiked recoveries of aniline in environmental water samples were in the range of 99.4-106.9% under the optimal conditions.The results indicated that the present method could be used as an alternative method for aniline determination in realworld water samples.
A new method for the determination of aniline in environmental water based on oscillopolarographic titration was presented in this paper.Several factors including the kind, concentration, and volume of acid, the dosage of potassium bromide, the temperature and concentration of concomitant substances were investigated in detail.The experimental results indicated that this method was simple, rapid, and sensitive.The linear range was 8.367×10-4 to 2.789×10-2 mol L-1, the relative standard deviation (R.S.D.) was lower than 0.96%, and the spiked recoveries of aniline in environmental water samples were in the range of 99.4-106.9% under the optimal conditions.The results indicated that the present method could be used as an alternative method for aniline determination in realworld water samples.
2007, 18(6): 734-737
doi: 10.1016/j.cclet.2007.04.029
Abstract:
A monolithic molecularly imprinted polymer with specific recognition ability for 4-hydroxybenzoic acid (4-HBA) was prepared by in situ photopolymerization, using methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EDMA) as a cross-linking agent, toluene and isooctane as porogenic solvents and Irgacure 1800 as an initiator.Baseline separation of isomers of hydroxybenzoic acid was achieved in less than 8 min on this monolithic column using 4-HBA as template, but not on the blank polymer.Furthermore, some neutral compounds could also be baseline-separated on the imprinted polymer column in the mode of pressure-driven capillary electrochromatography.
A monolithic molecularly imprinted polymer with specific recognition ability for 4-hydroxybenzoic acid (4-HBA) was prepared by in situ photopolymerization, using methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EDMA) as a cross-linking agent, toluene and isooctane as porogenic solvents and Irgacure 1800 as an initiator.Baseline separation of isomers of hydroxybenzoic acid was achieved in less than 8 min on this monolithic column using 4-HBA as template, but not on the blank polymer.Furthermore, some neutral compounds could also be baseline-separated on the imprinted polymer column in the mode of pressure-driven capillary electrochromatography.
2007, 18(6): 738-740
doi: 10.1016/j.cclet.2007.04.016
Abstract:
The phase behavior of supercritical (SC) CO2+PEG1000 (PEG with average molecular weight of 1000 g/mol)+n-butanol system was studied.It was demonstrated that SC CO2 could induce phase separation of PEG 1000+n-butanol system under suitable conditions.This hints that SC CO2 has potential applications in the separation of mixtures of PEG+organic compound.
The phase behavior of supercritical (SC) CO2+PEG1000 (PEG with average molecular weight of 1000 g/mol)+n-butanol system was studied.It was demonstrated that SC CO2 could induce phase separation of PEG 1000+n-butanol system under suitable conditions.This hints that SC CO2 has potential applications in the separation of mixtures of PEG+organic compound.
2007, 18(6): 741-743
doi: 10.1016/j.cclet.2007.04.038
Abstract:
The effects of ionic emulsifier, sodium dodecylbenzene sulfate (SDBS), on the formation of the multihollow structures in sub-micron sized polymer particles produced by alkali/acid posttreatment were investigated.The original latex particles with narrow size distribution were synthesized by a new sequence emulsifier-free/emulsifier emulsion copolymerization of styrene (St) and methacrylic acid (MAA).Results indicated that the pore size decreased and the pore number increased with the increase of SDBS amount, and the morphology of the posttreated latex particles was also significantly influenced by the introducing time of SDBS in the preparation of the original latex particles, and a suitable introducing time was 3 h of polymerization.
The effects of ionic emulsifier, sodium dodecylbenzene sulfate (SDBS), on the formation of the multihollow structures in sub-micron sized polymer particles produced by alkali/acid posttreatment were investigated.The original latex particles with narrow size distribution were synthesized by a new sequence emulsifier-free/emulsifier emulsion copolymerization of styrene (St) and methacrylic acid (MAA).Results indicated that the pore size decreased and the pore number increased with the increase of SDBS amount, and the morphology of the posttreated latex particles was also significantly influenced by the introducing time of SDBS in the preparation of the original latex particles, and a suitable introducing time was 3 h of polymerization.
2007, 18(6): 744-746
doi: 10.1016/j.cclet.2007.04.011
Abstract:
Aliphatic polyesters were synthesized via the ring opening polymerization of the corresponding lactones initiated with dibutylmagnesium both in bulk and in solution.The resulting polymers were characterized by 1H, 13C NMR, GPC and XRD.The results indicated that dibutylmagnesium is an effective initiator for the ring opening polymerization of lactones.
Aliphatic polyesters were synthesized via the ring opening polymerization of the corresponding lactones initiated with dibutylmagnesium both in bulk and in solution.The resulting polymers were characterized by 1H, 13C NMR, GPC and XRD.The results indicated that dibutylmagnesium is an effective initiator for the ring opening polymerization of lactones.
2007, 18(6): 747-749
doi: 10.1016/j.cclet.2007.04.037
Abstract:
The aqueous solutions of poly (ε-caprolactone-co-lactide)-poly (ethylene glycol) poly (ε-caprolactone-co-lactide) undergoing sol-gel transition as the temperature increases from 20 to 50℃ were successfully prepared.The thermogelling triblock copolymers were synthesized by subtle tuning of the chemical composition and the hydrophilicity/hydrophobicity balance.The sol-gel transition was studied focusing on structure-property relationship.The amphiphilic copolymer formed micelles in aqueous solutions.It is believed to have potential applications in drug delivery and tissue engineering.
The aqueous solutions of poly (ε-caprolactone-co-lactide)-poly (ethylene glycol) poly (ε-caprolactone-co-lactide) undergoing sol-gel transition as the temperature increases from 20 to 50℃ were successfully prepared.The thermogelling triblock copolymers were synthesized by subtle tuning of the chemical composition and the hydrophilicity/hydrophobicity balance.The sol-gel transition was studied focusing on structure-property relationship.The amphiphilic copolymer formed micelles in aqueous solutions.It is believed to have potential applications in drug delivery and tissue engineering.
2007, 18(6): 750-753
doi: 10.1016/j.cclet.2007.04.018
Abstract:
1, 3-Benzodioxole (BDO) as a simple model compound for the BDO derivatives from natural plant was used as coinitiator for p-chlorobenzophenone (CBP) and initiator for UV photopolymerization of 1, 6-hexanedioldiacrylate (HDDA), respectively.The results showed that, BDO was an effective coinitiator for CBP.Although BDO as initiator led to very low rate of polymerization, it was still meaningful for the photocuring field.
1, 3-Benzodioxole (BDO) as a simple model compound for the BDO derivatives from natural plant was used as coinitiator for p-chlorobenzophenone (CBP) and initiator for UV photopolymerization of 1, 6-hexanedioldiacrylate (HDDA), respectively.The results showed that, BDO was an effective coinitiator for CBP.Although BDO as initiator led to very low rate of polymerization, it was still meaningful for the photocuring field.
2007, 18(6): 754-757
doi: 10.1016/j.cclet.2007.04.006
Abstract:
A highly branched polycarbosilane bearing allyl groups has been prepared by a one-pot synthesis with chloromethyltrichlorosilane, chloromethylmethyldichlorosilane and allyl chloride as the starting materials.The resultant polymer, with the approximate formula[SiH1.2(CH3)0.71(CH2CH=CH2)0.09CH2]n, has been characterized by 1H, 13C, and 29Si NMR, GPC, TG and elemental analysis.It could be cross-linked thermally at 170℃ in the absence of oxygen.Pyrolysis of the polymer gave a ceramic with a yield of about 70%.
A highly branched polycarbosilane bearing allyl groups has been prepared by a one-pot synthesis with chloromethyltrichlorosilane, chloromethylmethyldichlorosilane and allyl chloride as the starting materials.The resultant polymer, with the approximate formula[SiH1.2(CH3)0.71(CH2CH=CH2)0.09CH2]n, has been characterized by 1H, 13C, and 29Si NMR, GPC, TG and elemental analysis.It could be cross-linked thermally at 170℃ in the absence of oxygen.Pyrolysis of the polymer gave a ceramic with a yield of about 70%.
Synthesis of core-shell structured polymers with inserted thioether from a multi-functional scaffold
2007, 18(6): 758-761
doi: 10.1016/j.cclet.2007.04.005
Abstract:
The synthesis of a thioether inserted, core-shell structured polymer from the scaffold of hyperbranched polyglycerol (PG) was described.PG was first allyl functionalized, and in the presence of AIBN, the allyl groups further underwent radical addition to thiol compounds, thus thiol functional polyethylene oxide monomether (MPEO) were grafted onto PG.Similarly, 2-mercaptoethylammonium chloride was introduced onto PG via thiol addition, and the residual amino groups were further quaternized with decyl bromide, leading to an amphiphilic core-shell structure polymer.
The synthesis of a thioether inserted, core-shell structured polymer from the scaffold of hyperbranched polyglycerol (PG) was described.PG was first allyl functionalized, and in the presence of AIBN, the allyl groups further underwent radical addition to thiol compounds, thus thiol functional polyethylene oxide monomether (MPEO) were grafted onto PG.Similarly, 2-mercaptoethylammonium chloride was introduced onto PG via thiol addition, and the residual amino groups were further quaternized with decyl bromide, leading to an amphiphilic core-shell structure polymer.
2007, 18(6): 762-763
doi: 10.1016/j.cclet.2007.03.009
Abstract:
A novel siloxane-containing diamine, bis[4-(p-aminophenoxy) phenoxy]dimethylsilane (APPMS), was successfully synthesized in three steps using hydroquinone as starting material, which was reacted with 4, 4'-oxydiphthalic anhydride (ODPA) via a conventional two-step thermal or chemical imidization method to produce a new siloxane-containing polyimide.The resulting polyimide exhibited excellent solubility, and film-forming capability.
A novel siloxane-containing diamine, bis[4-(p-aminophenoxy) phenoxy]dimethylsilane (APPMS), was successfully synthesized in three steps using hydroquinone as starting material, which was reacted with 4, 4'-oxydiphthalic anhydride (ODPA) via a conventional two-step thermal or chemical imidization method to produce a new siloxane-containing polyimide.The resulting polyimide exhibited excellent solubility, and film-forming capability.
2007, 18(6): 764-767
doi: 10.1016/j.cclet.2007.04.021
Abstract:
In this work, a new method of a series of ion liquids (ILs) l-alkyl-3-methylimidazolium chloride[Cnmim]Cl (n=2, 4, 6, 8) intercalation into layered zirconium phosphates was investigated.It was found that the α-ZrP-2BA (i.e.pre-intercalated BA was arranged in a bilayer mode in the galleries ofα-ZrP) was a suitable host for intercalation ILs:ILs was inserted through exchanging pre-intercalated BA.And the intercalation orientation was investigated by use of X-ray diffraction (XRD) experiments and molecular modeling calculation.
In this work, a new method of a series of ion liquids (ILs) l-alkyl-3-methylimidazolium chloride[Cnmim]Cl (n=2, 4, 6, 8) intercalation into layered zirconium phosphates was investigated.It was found that the α-ZrP-2BA (i.e.pre-intercalated BA was arranged in a bilayer mode in the galleries ofα-ZrP) was a suitable host for intercalation ILs:ILs was inserted through exchanging pre-intercalated BA.And the intercalation orientation was investigated by use of X-ray diffraction (XRD) experiments and molecular modeling calculation.
