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2011 Volume 22 Issue 10
2011, 22(10): 1135-1138
doi: 10.1016/j.cclet.2011.05.010
Abstract:
The first total syntheses of bipinnatone A and B have been achieved starting from commercially available phloroglucinol, p-hydroxybenzaldehyde in ten steps. Key features of the syntheses include Aldol reaction, aryl-alkylation and InCl3-NaBH4 selective reduction.
The first total syntheses of bipinnatone A and B have been achieved starting from commercially available phloroglucinol, p-hydroxybenzaldehyde in ten steps. Key features of the syntheses include Aldol reaction, aryl-alkylation and InCl3-NaBH4 selective reduction.
2011, 22(10): 1139-1142
doi: 10.1016/j.cclet.2011.05.032
Abstract:
On the propose of searching for the SAR and obtaining novel antiplatelet aggregating drugs, we have described the synthesis procedure and the activities in vitro on antiplatelet aggregation of two series of derivatives, which contain both 18 N, N'-di (2-substitutedphenyl)-4-methoxyisophthalamides (2a-2r) of the 2 series and nine N, N'-di (2-substitutedphenyl)-4-methoxybenzene-1, 3-disulfonamides (3a-3i) of the 3 series. The results showed that three compounds 2e, 2i and 3g emerged as significant activities of antiplatelet aggregation, superior to two reference drugs picotamide and aspirin, and eight compounds 2j, 2k, 2l, 2o, 2p, 2q, 2r and 3i merely superior to picotamide. The preliminary SAR shows that it is favorable for the 2 series to increase the activities via the steric hindrance substituents attached to the two side chain benzene rings at 2-positions. And the arylamides of the 2 series have better the activity values than the arylsulfonamides of the 3 series respective except for 3b and 3g. On the contrary, electrostatic factors would not contribute evidently to the activities of the two series. The structures of 15 compounds newly synthesized have been established by MS and 1H NMR and been first reported in this paper.
On the propose of searching for the SAR and obtaining novel antiplatelet aggregating drugs, we have described the synthesis procedure and the activities in vitro on antiplatelet aggregation of two series of derivatives, which contain both 18 N, N'-di (2-substitutedphenyl)-4-methoxyisophthalamides (2a-2r) of the 2 series and nine N, N'-di (2-substitutedphenyl)-4-methoxybenzene-1, 3-disulfonamides (3a-3i) of the 3 series. The results showed that three compounds 2e, 2i and 3g emerged as significant activities of antiplatelet aggregation, superior to two reference drugs picotamide and aspirin, and eight compounds 2j, 2k, 2l, 2o, 2p, 2q, 2r and 3i merely superior to picotamide. The preliminary SAR shows that it is favorable for the 2 series to increase the activities via the steric hindrance substituents attached to the two side chain benzene rings at 2-positions. And the arylamides of the 2 series have better the activity values than the arylsulfonamides of the 3 series respective except for 3b and 3g. On the contrary, electrostatic factors would not contribute evidently to the activities of the two series. The structures of 15 compounds newly synthesized have been established by MS and 1H NMR and been first reported in this paper.
2011, 22(10): 1143-1146
doi: 10.1016/j.cclet.2011.05.021
Abstract:
An efficient synthesis of 1, 3-oxathiolane-2-imin derivatives is described via one-pot reaction between arylisothiocyanats, asymmetrically substituted oxiranes and catalytic amount of methanol. The mild reaction conditions and high yields of the products exhibit the good synthetic advantage of this method.
An efficient synthesis of 1, 3-oxathiolane-2-imin derivatives is described via one-pot reaction between arylisothiocyanats, asymmetrically substituted oxiranes and catalytic amount of methanol. The mild reaction conditions and high yields of the products exhibit the good synthetic advantage of this method.
2011, 22(10): 1147-1150
doi: 10.1016/j.cclet.2011.05.045
Abstract:
Two tribranched chromophores, 1, 3, 5-triazine as electron deficient core, 9, 9-dimethylfluorene as π-conjugated bridge, diphenylamino (4a) and naphthylamino (4b) as electron-donating end-groups, were successfully prepared via Buchwald-Hartwig coupling reaction. Their linear photophysical and two-photon absorption (TPA) properties were investigated by absorption, fluorescence and nonlinear transmission method, respectively. The absorption cut-offs of the chromophores are below 550 run and both chromophores have strong fluorescence emission. The compound 4a (206.3 GM) exhibits larger TPA cross-section than 4b (57.8 GM) in the femtosecond regime at 800 nm.
Two tribranched chromophores, 1, 3, 5-triazine as electron deficient core, 9, 9-dimethylfluorene as π-conjugated bridge, diphenylamino (4a) and naphthylamino (4b) as electron-donating end-groups, were successfully prepared via Buchwald-Hartwig coupling reaction. Their linear photophysical and two-photon absorption (TPA) properties were investigated by absorption, fluorescence and nonlinear transmission method, respectively. The absorption cut-offs of the chromophores are below 550 run and both chromophores have strong fluorescence emission. The compound 4a (206.3 GM) exhibits larger TPA cross-section than 4b (57.8 GM) in the femtosecond regime at 800 nm.
2011, 22(10): 1151-1154
doi: 10.1016/j.cclet.2011.04.012
Abstract:
A highly selective synthesis of 2-aryl-1-arylmethyl-1H-1, 3-benzimidazoles from the reaction of o-phenylenediamine and aromatic aldehydes in the presence of sulfuric acid {[3-(3-silicapropyl)sulfanyl]propyl}Jester (SASPSPE) in water and at 80℃ in good to excellent yields.
A highly selective synthesis of 2-aryl-1-arylmethyl-1H-1, 3-benzimidazoles from the reaction of o-phenylenediamine and aromatic aldehydes in the presence of sulfuric acid {[3-(3-silicapropyl)sulfanyl]propyl}Jester (SASPSPE) in water and at 80℃ in good to excellent yields.
2011, 22(10): 1155-1158
doi: 10.1016/j.cclet.2011.04.013
Abstract:
A series of new ligands L1-L7 were readily prepared in one step. Friedel-Crafts alkylation of indoles with nitroalkenes catalyzed by a novel Cu (Ⅱ)-L complex has been developed. The remarkable advantages of this reaction are mild reaction conditions, simple workup procedure, high yields of products and the use of ethanol as a green solvent.
A series of new ligands L1-L7 were readily prepared in one step. Friedel-Crafts alkylation of indoles with nitroalkenes catalyzed by a novel Cu (Ⅱ)-L complex has been developed. The remarkable advantages of this reaction are mild reaction conditions, simple workup procedure, high yields of products and the use of ethanol as a green solvent.
2011, 22(10): 1159-1162
doi: 10.1016/j.cclet.2011.04.016
Abstract:
A novel and efficient synthetic method of atorvastatin was described. The key step of the synthesis was the construction of the olefin linkage between the chiral side chain and skeleton via a Horner-Wadsworth-Emmons reaction, resulting in the advanced intermediate of atorvastatin under hydrogenation of the olefin over Pd/C. This novel method is more useful for the practical synthesis of atorvastatin than its document reported methods.
A novel and efficient synthetic method of atorvastatin was described. The key step of the synthesis was the construction of the olefin linkage between the chiral side chain and skeleton via a Horner-Wadsworth-Emmons reaction, resulting in the advanced intermediate of atorvastatin under hydrogenation of the olefin over Pd/C. This novel method is more useful for the practical synthesis of atorvastatin than its document reported methods.
2011, 22(10): 1163-1166
doi: 10.1016/j.cclet.2011.05.011
Abstract:
2, 3-Dihydroquinazolin-4 (1H)-ones have been synthesized in the high to excellent yields via condensation of 2-aminobenzamide with aldehydes and ketones in the presence of catalytic amount of ZrCl4 in EtOH at room temperature. Mild reaction conditions, clean reaction media, simple workup and easy purification are advantages of this methodology.
2, 3-Dihydroquinazolin-4 (1H)-ones have been synthesized in the high to excellent yields via condensation of 2-aminobenzamide with aldehydes and ketones in the presence of catalytic amount of ZrCl4 in EtOH at room temperature. Mild reaction conditions, clean reaction media, simple workup and easy purification are advantages of this methodology.
2011, 22(10): 1167-1170
doi: 10.1016/j.cclet.2011.05.009
Abstract:
Several new asymmetric substituted dicarbamates were synthesized with a convenient route. Firstly, tolylene-2, 4-diisocyanate dimmer was obtained from monomer with tributylphosphine as catalyst. Then, the dimmer reacted with alcohol (R1OH) to prepare carbamate substituted uretidione. Finally, uretidione ring was opened and the released isocyanate reacted with another alcohol (R2OH, R1≠R2).
Several new asymmetric substituted dicarbamates were synthesized with a convenient route. Firstly, tolylene-2, 4-diisocyanate dimmer was obtained from monomer with tributylphosphine as catalyst. Then, the dimmer reacted with alcohol (R1OH) to prepare carbamate substituted uretidione. Finally, uretidione ring was opened and the released isocyanate reacted with another alcohol (R2OH, R1≠R2).
2011, 22(10): 1171-1174
doi: 10.1016/j.cclet.2011.05.007
Abstract:
A combination of tetrachlorosilane (TCS) and phenol in dichloromethane was found to be an efficient reagent for hydro-chlorination of α, β-unsaturated ketones to afford the corresponding β-chloroketones in good yield at ambient temperature. Reactions of the titled compounds with TCS-NaN3 as well as with nitriles utilizing TCS-ZnCl2 to give 1, 5-disubstituted tetrazole derivatives or β-amido ketones respectively are also described.
A combination of tetrachlorosilane (TCS) and phenol in dichloromethane was found to be an efficient reagent for hydro-chlorination of α, β-unsaturated ketones to afford the corresponding β-chloroketones in good yield at ambient temperature. Reactions of the titled compounds with TCS-NaN3 as well as with nitriles utilizing TCS-ZnCl2 to give 1, 5-disubstituted tetrazole derivatives or β-amido ketones respectively are also described.
2011, 22(10): 1175-1178
doi: 10.1016/j.cclet.2011.05.014
Abstract:
The commercially available diphosphane ligand MeO-BIPHEP was first investigated in the palladium-catalyzed Sonogashira reaction in the absence of copper and amine. The coupling of various aryl bromides and aryl chlorides with phenylacetylene gave moderate to excellent yields.
The commercially available diphosphane ligand MeO-BIPHEP was first investigated in the palladium-catalyzed Sonogashira reaction in the absence of copper and amine. The coupling of various aryl bromides and aryl chlorides with phenylacetylene gave moderate to excellent yields.
2011, 22(10): 1179-1182
doi: 10.1016/j.cclet.2011.05.015
Abstract:
Potassium tert-butoxide has been found to be a highly efficient catalyst for one-pot, three-component reaction of aryl aldehydes, acetophenones, and thiols via Claisen-Schmidt/Michael addition reactions for the synthesis of thia-Michael adducts in high yields. The reactions are best carried out in tert-butyl alcohol at room temperature.
Potassium tert-butoxide has been found to be a highly efficient catalyst for one-pot, three-component reaction of aryl aldehydes, acetophenones, and thiols via Claisen-Schmidt/Michael addition reactions for the synthesis of thia-Michael adducts in high yields. The reactions are best carried out in tert-butyl alcohol at room temperature.
2011, 22(10): 1183-1186
doi: 10.1016/j.cclet.2011.04.020
Abstract:
A series of pyrido[2, 3-d]pyrimidine derivatives were easily constructed by cyclocondensation reactions of 6-aminouracils or 6-aminothiouracil with α, β-unsaturated carbonyl compounds (aldehyde, ketone and ester) possessing a leaving group on the β position, in H2O under reflux conditions.
A series of pyrido[2, 3-d]pyrimidine derivatives were easily constructed by cyclocondensation reactions of 6-aminouracils or 6-aminothiouracil with α, β-unsaturated carbonyl compounds (aldehyde, ketone and ester) possessing a leaving group on the β position, in H2O under reflux conditions.
2011, 22(10): 1187-1190
doi: 10.1016/j.cclet.2011.05.016
Abstract:
Silica chloride catalysted one pot cyclocondensation of aldehydes, ethyl acetoacetate and phenyl hydrazine leading to substituted pyrazoles has been reported.
Silica chloride catalysted one pot cyclocondensation of aldehydes, ethyl acetoacetate and phenyl hydrazine leading to substituted pyrazoles has been reported.
2011, 22(10): 1191-1194
doi: 10.1016/j.cclet.2011.05.017
Abstract:
New Schiff base liquid crystals containing benzoxazole core and alkanoyloxy chain at the end group of the molecules (Cn-1H2n-1COO-, n=14, 16, 18) was synthesized. The present compounds are enantiotropic smectic A liquid crystals. It was also found that the end groups of the molecules and polar chloro substituent at the benzoxazole fragment had effect on the mesomorphic properties.
New Schiff base liquid crystals containing benzoxazole core and alkanoyloxy chain at the end group of the molecules (Cn-1H2n-1COO-, n=14, 16, 18) was synthesized. The present compounds are enantiotropic smectic A liquid crystals. It was also found that the end groups of the molecules and polar chloro substituent at the benzoxazole fragment had effect on the mesomorphic properties.
2011, 22(10): 1195-1198
doi: 10.1016/j.cclet.2011.05.005
Abstract:
The dibromination of alkenes and alkynes with bromosuccinimide and sodium bromide catalyzed by FeBr3 under mild conditions has been developed. The trans-dibromo compounds were exclusively obtained with excellent yields.
The dibromination of alkenes and alkynes with bromosuccinimide and sodium bromide catalyzed by FeBr3 under mild conditions has been developed. The trans-dibromo compounds were exclusively obtained with excellent yields.
2011, 22(10): 1199-1202
doi: 10.1016/j.cclet.2011.05.003
Abstract:
An efficient synthesis of 1, 4-dihydropyridines using lanthanum oxide as a catalyst from aldehydes, β-ketoester and ammonium acetate without solvent under the irradiation of microwave is described. Compared with the classical Hantzsch reaction, this new method has the advantage of good yield (90-98%) and short reaction time (40-80 s).
An efficient synthesis of 1, 4-dihydropyridines using lanthanum oxide as a catalyst from aldehydes, β-ketoester and ammonium acetate without solvent under the irradiation of microwave is described. Compared with the classical Hantzsch reaction, this new method has the advantage of good yield (90-98%) and short reaction time (40-80 s).
2011, 22(10): 1203-1206
doi: 10.1016/j.cclet.2011.05.019
Abstract:
TiO2 nanoparticles (TiO2 NPs) worked as an efficient heterogeneous catalyst in a one-pot, three-component, and solvent free Mannich reaction; producing various β-aminocarbonyls in good yields, and with good stereoselectivities. The catalyst was easily separated from the reaction mixture and was recycled four times with no significant loss of its catalytic activity.
TiO2 nanoparticles (TiO2 NPs) worked as an efficient heterogeneous catalyst in a one-pot, three-component, and solvent free Mannich reaction; producing various β-aminocarbonyls in good yields, and with good stereoselectivities. The catalyst was easily separated from the reaction mixture and was recycled four times with no significant loss of its catalytic activity.
2011, 22(10): 1207-1210
doi: 10.1016/j.cclet.2011.05.020
Abstract:
Trimethylsilylation of alcohols was achieved using 1, 1, 1, 3, 3, 3-hexamethyldisilazane (HMDS) as silylating agent, in the presence of polyvinylpolypyrrolidonium tribromide in acetonitrile at room temperature. Also a variety of alcohols were converted into alkyl formates by ethyl formate and a catalytic amount of polyvinylpolypyrrolidonium tribromide under solvent free conditions at room temperature.
Trimethylsilylation of alcohols was achieved using 1, 1, 1, 3, 3, 3-hexamethyldisilazane (HMDS) as silylating agent, in the presence of polyvinylpolypyrrolidonium tribromide in acetonitrile at room temperature. Also a variety of alcohols were converted into alkyl formates by ethyl formate and a catalytic amount of polyvinylpolypyrrolidonium tribromide under solvent free conditions at room temperature.
2011, 22(10): 1211-1214
doi: 10.1016/j.cclet.2011.05.002
Abstract:
Nanocrystalline TiO2 was used as an efficient and recyclable catalyst for the chemoselective trimethylsilylation of primary and less hindered secondary alcohols and phenols with hexamethyldisilazane (HMDS). All reactions were performed under mild and completely heterogeneous conditions in good to excellent yields.
Nanocrystalline TiO2 was used as an efficient and recyclable catalyst for the chemoselective trimethylsilylation of primary and less hindered secondary alcohols and phenols with hexamethyldisilazane (HMDS). All reactions were performed under mild and completely heterogeneous conditions in good to excellent yields.
2011, 22(10): 1215-1218
doi: 10.1016/j.cclet.2011.05.022
Abstract:
A series of gem-dimethyl-bearing C-glucosides were designed and synthesized as SGLT2 inhibitors, with anhydrous aluminum chloride-mediated Friedel-Crafts alkylation to construct the gem-dimethyl functionality being the key step. The in vivo anti-hyperglycemic activity was evaluated with mice oral glucose tolerance test (OGTT), and all the synthesized compounds showed significant but less potent anti-hyperglycemic activity than the positive control dapagliflozin.
A series of gem-dimethyl-bearing C-glucosides were designed and synthesized as SGLT2 inhibitors, with anhydrous aluminum chloride-mediated Friedel-Crafts alkylation to construct the gem-dimethyl functionality being the key step. The in vivo anti-hyperglycemic activity was evaluated with mice oral glucose tolerance test (OGTT), and all the synthesized compounds showed significant but less potent anti-hyperglycemic activity than the positive control dapagliflozin.
2011, 22(10): 1219-1222
doi: 10.1016/j.cclet.2011.05.026
Abstract:
A simple synthesis of 1, 2, 3, 5-tetrasubstituted pyrrole derivatives from the reaction of enaminone with α-haloketones, under solvent-free conditions, is described.
A simple synthesis of 1, 2, 3, 5-tetrasubstituted pyrrole derivatives from the reaction of enaminone with α-haloketones, under solvent-free conditions, is described.
2011, 22(10): 1223-1225
doi: 10.1016/j.cclet.2011.05.031
Abstract:
A series of novel 2-hydrazinylpyrido[2, 3-b]pyrazin-3 (4H)-one derivatives were synthesized and evaluated for their cytotoxic activities against A549, MDA-MB-231 and HT-29 cell lines in vitro. Pharmacological data indicated that compounds 5b, 5c, 10a and 10g possessed marked cytotoxicity, especially 10a (with IC50 values of 0.81, 2.56 and 1.63 μmol/L against A549, MDA-MB-231 and HT29 cell lines, respectively), which had emerged as a lead compound.
A series of novel 2-hydrazinylpyrido[2, 3-b]pyrazin-3 (4H)-one derivatives were synthesized and evaluated for their cytotoxic activities against A549, MDA-MB-231 and HT-29 cell lines in vitro. Pharmacological data indicated that compounds 5b, 5c, 10a and 10g possessed marked cytotoxicity, especially 10a (with IC50 values of 0.81, 2.56 and 1.63 μmol/L against A549, MDA-MB-231 and HT29 cell lines, respectively), which had emerged as a lead compound.
2011, 22(10): 1226-1228
doi: 10.1016/j.cclet.2011.05.036
Abstract:
A new compound, 3-butyryl-6-[rel-(1S, 2S)-1, 2-dihydroxypropyl]-4-hydroxy-2H-pyran-2-one (1), was isolated from the solid fermented rice culture of Alternaria sp. CIB 108, along with three known ones, deoxyradicinin (2), 3-epiradicinol (3), and 3-epideoxyradicinol (4). Their structures were elucidated on the basis of spectroscopic data. The single crystal X-ray diffraction was applied to further clarify the structure of 1. Furthermore, compounds 1-4 possessed no cytotoxicity against several cell lines (HeLa, HepG2, and Ros) and showed no antibacterial activity at 40 μmol/L.
A new compound, 3-butyryl-6-[rel-(1S, 2S)-1, 2-dihydroxypropyl]-4-hydroxy-2H-pyran-2-one (1), was isolated from the solid fermented rice culture of Alternaria sp. CIB 108, along with three known ones, deoxyradicinin (2), 3-epiradicinol (3), and 3-epideoxyradicinol (4). Their structures were elucidated on the basis of spectroscopic data. The single crystal X-ray diffraction was applied to further clarify the structure of 1. Furthermore, compounds 1-4 possessed no cytotoxicity against several cell lines (HeLa, HepG2, and Ros) and showed no antibacterial activity at 40 μmol/L.
2011, 22(10): 1229-1232
doi: 10.1016/j.cclet.2011.04.007
Abstract:
A new phycocyanin (PC) fluorescent subunit named β2 (18 kDa) was isolated and characterized by both SDS-PAGE and isoelectric focusing (IEF) from a species of cryptophytic alga Chroomonas placoidea. PC was separated and purified by ammonium sulfate sedimentation followed by two steps of Sephadex G-100 chromatography. After denatured in 4 mol/L urea for 48 h, PC was divided into two fractions by passing through a Sephacryl S-100 chromatography column twice. The blue fraction (S-1) contained β subunits with a maximal absorbance at 595 nm in visible light region. While the green fraction (S-2) enriched in α subunits showed a characteristic long wavelength absorbance at 680-700 nm region and exhibited a relatively low molecular weight of 9.4 (α1) and 8.5 kDa (α2). Fraction S-1 also consisted of two different fluorescent subunits with molecular weight of 20.1 kDa (β1) and 18 kDa (β2) and differed from each other on isoelectric points of pH 5.7 (β1) and 6.0 (β2), respectively. Further investigation of peptide sequence will help a lot in elucidating the new subunit β2 that was smaller in size and more neutral than the known β1subunit, and may provide an alternative explanation in structure of cryptophytic phycobiliproteins.
A new phycocyanin (PC) fluorescent subunit named β2 (18 kDa) was isolated and characterized by both SDS-PAGE and isoelectric focusing (IEF) from a species of cryptophytic alga Chroomonas placoidea. PC was separated and purified by ammonium sulfate sedimentation followed by two steps of Sephadex G-100 chromatography. After denatured in 4 mol/L urea for 48 h, PC was divided into two fractions by passing through a Sephacryl S-100 chromatography column twice. The blue fraction (S-1) contained β subunits with a maximal absorbance at 595 nm in visible light region. While the green fraction (S-2) enriched in α subunits showed a characteristic long wavelength absorbance at 680-700 nm region and exhibited a relatively low molecular weight of 9.4 (α1) and 8.5 kDa (α2). Fraction S-1 also consisted of two different fluorescent subunits with molecular weight of 20.1 kDa (β1) and 18 kDa (β2) and differed from each other on isoelectric points of pH 5.7 (β1) and 6.0 (β2), respectively. Further investigation of peptide sequence will help a lot in elucidating the new subunit β2 that was smaller in size and more neutral than the known β1subunit, and may provide an alternative explanation in structure of cryptophytic phycobiliproteins.
2011, 22(10): 1233-1236
doi: 10.1016/j.cclet.2011.05.018
Abstract:
A new iridoid glucoside, 10-O-veratroyleranthemoside (1) was isolated from the roots of Wendlandia tinctoria. The structure was established by spectroscopic (including 2D NMR) and chemical methods.
A new iridoid glucoside, 10-O-veratroyleranthemoside (1) was isolated from the roots of Wendlandia tinctoria. The structure was established by spectroscopic (including 2D NMR) and chemical methods.
2011, 22(10): 1237-1240
doi: 10.1016/j.cclet.2011.04.011
Abstract:
A method based on capillary electrophoresis coupled with amperometric detection (CE-AD) has been developed for the separation and determination of kaempferol, ferulic acid, vanillic acid, caffeic acid, gallic acid and protocatechuic acid in blueberry wine for the first time. In order to get the optimum conditions of separation, the effects of working electrode potential, pH value and concentration of running buffer, separation voltage and injection time on CE-AD were investigated. Under the optimum conditions, the analytes could be separated in Na2B4O7-KH2PO4 buffer at pH 7.8 within 18 min. A 300 μm diameter carbon disk electrode had good current responses at +0.95 V (vs. SCE) for all analytes. The responses were linear with concentrations over three orders of magnitude with detection limits (S/N=3) at 10-8 g/mL magnitude for the analytes and the recoveries were in the range of 95.8-106.7%. The method could be successfully applied to the analysis of real sample with satisfactory results and therefore recommended for use by the quality control departments of fruit wine producers.
A method based on capillary electrophoresis coupled with amperometric detection (CE-AD) has been developed for the separation and determination of kaempferol, ferulic acid, vanillic acid, caffeic acid, gallic acid and protocatechuic acid in blueberry wine for the first time. In order to get the optimum conditions of separation, the effects of working electrode potential, pH value and concentration of running buffer, separation voltage and injection time on CE-AD were investigated. Under the optimum conditions, the analytes could be separated in Na2B4O7-KH2PO4 buffer at pH 7.8 within 18 min. A 300 μm diameter carbon disk electrode had good current responses at +0.95 V (vs. SCE) for all analytes. The responses were linear with concentrations over three orders of magnitude with detection limits (S/N=3) at 10-8 g/mL magnitude for the analytes and the recoveries were in the range of 95.8-106.7%. The method could be successfully applied to the analysis of real sample with satisfactory results and therefore recommended for use by the quality control departments of fruit wine producers.
2011, 22(10): 1241-1244
doi: 10.1016/j.cclet.2011.04.019
Abstract:
Near infrared (NIR) spectroscopy technique has shown great power and gained wide acceptance for analyzing complicated samples. The present work is to distinguish different brands of tobacco products by using on-line NIR spectroscopy and pattern recognition techniques. Moreover, since each brand contains a large number of samples, an improved dendrogram was proposed to show the classification of different brands. The results suggest that MR spectroscopy combined with principal component analysis (PCA) and hierarchical cluster analysis (HCA) performs well in discrimination of the different brands, and the improved dendrogram could provide more information about the difference of the brands.
Near infrared (NIR) spectroscopy technique has shown great power and gained wide acceptance for analyzing complicated samples. The present work is to distinguish different brands of tobacco products by using on-line NIR spectroscopy and pattern recognition techniques. Moreover, since each brand contains a large number of samples, an improved dendrogram was proposed to show the classification of different brands. The results suggest that MR spectroscopy combined with principal component analysis (PCA) and hierarchical cluster analysis (HCA) performs well in discrimination of the different brands, and the improved dendrogram could provide more information about the difference of the brands.
2011, 22(10): 1245-1248
doi: 10.1016/j.cclet.2011.05.023
Abstract:
A novel high performance liquid chromatography-chemiluminescence (HPLC-CL) method for investigation of in vitro metabolism of repaglinide in pig liver microsomes with microdialysis sampling technique was developed. The chromatographic separation was performed on a Hypersil BDS-C18 column with an isocratic mobile phase consisting of methanol and 0.01 mol/L KH2PO4 (pH 3.0) (volume ratio 75:25) at a flow rate of 1.0 mL/min. The detection was based on the chemiluminescence reaction of repaglinide with acidic potassium permanganate (KMnO4) and tris (2, 2'-bipyridyl)ruthenium (III) (Ru (bpy)33+), which was immobilized on the cationic ion-exchange resin for obtaining high sensitivity and reducing consumption of expensive reagent.
A novel high performance liquid chromatography-chemiluminescence (HPLC-CL) method for investigation of in vitro metabolism of repaglinide in pig liver microsomes with microdialysis sampling technique was developed. The chromatographic separation was performed on a Hypersil BDS-C18 column with an isocratic mobile phase consisting of methanol and 0.01 mol/L KH2PO4 (pH 3.0) (volume ratio 75:25) at a flow rate of 1.0 mL/min. The detection was based on the chemiluminescence reaction of repaglinide with acidic potassium permanganate (KMnO4) and tris (2, 2'-bipyridyl)ruthenium (III) (Ru (bpy)33+), which was immobilized on the cationic ion-exchange resin for obtaining high sensitivity and reducing consumption of expensive reagent.
2011, 22(10): 1249-1252
doi: 10.1016/j.cclet.2011.03.021
Abstract:
Novel self cross-linking fluorinated acrylic latex (SCLFAL) has been successfully prepared via starved seeded semi-batch emulsion polymerization. The resultant SCLFAL is characterized by Fourier transform infrared (FTTR) spectrometry. Contact angle (CA) and glass transition temperature (Tg) of the film are investigated. Results show that CA and Tg of the film can be improved when the moderate amount of HPMA is introduced into the mixed monomers.
Novel self cross-linking fluorinated acrylic latex (SCLFAL) has been successfully prepared via starved seeded semi-batch emulsion polymerization. The resultant SCLFAL is characterized by Fourier transform infrared (FTTR) spectrometry. Contact angle (CA) and glass transition temperature (Tg) of the film are investigated. Results show that CA and Tg of the film can be improved when the moderate amount of HPMA is introduced into the mixed monomers.
2011, 22(10): 1253-1256
doi: 10.1016/j.cclet.2011.03.022
Abstract:
A simple one-bath strategy has been developed to synthesize a novel CdTe@SiO2@MIP (molecularly imprinted and silica-functionalized CdTe quantum dots, MISFQDs), in which a silica shell was coated on the surface of CdTe quantum dots (CdTe@SiO2 QDs) and then a polymer for selective recognition of 4-chlorophenol (4-CP) was constructed on the surface of CdTe@SiO2 QDs using mercaptoacetic acid as stabilizer, 3-aminopropyl-trimethoxysilane (APTES) as functional monomers and tetraethoxysilane (TEOS) as crosslink agent. The structures of CdTe@SiO2@MIP were analyzed by ultraviolet-visible absorption, Fluorescence, FT-IR spectrum and powder X-ray diffraction. The application and characterization of the CdTe@SiO2@MIP were investigated by experiments. All results indicated that the CdTe@SiO2@MIP can selectively recognize 4-chlorophenol.
A simple one-bath strategy has been developed to synthesize a novel CdTe@SiO2@MIP (molecularly imprinted and silica-functionalized CdTe quantum dots, MISFQDs), in which a silica shell was coated on the surface of CdTe quantum dots (CdTe@SiO2 QDs) and then a polymer for selective recognition of 4-chlorophenol (4-CP) was constructed on the surface of CdTe@SiO2 QDs using mercaptoacetic acid as stabilizer, 3-aminopropyl-trimethoxysilane (APTES) as functional monomers and tetraethoxysilane (TEOS) as crosslink agent. The structures of CdTe@SiO2@MIP were analyzed by ultraviolet-visible absorption, Fluorescence, FT-IR spectrum and powder X-ray diffraction. The application and characterization of the CdTe@SiO2@MIP were investigated by experiments. All results indicated that the CdTe@SiO2@MIP can selectively recognize 4-chlorophenol.
2011, 22(10): 1257-1260
doi: 10.1016/j.cclet.2011.04.015
Abstract:
A novel functional polyacetylene containing fluorene group as a pendant, poly (2-(p-methylstyrene)-7-acetylene-9, 9-dioctyl-fluorene), was synthesized in moderate yield by[Rh (nbd)Cl]2-Et3N catalyst. The structures and properties of monomer and polymer were characterized and evaluated with FTIR, NMR, UV-vis, GPC and Z-scan, respectively. The results show that the incorporation of fluorene into polyacetylene has endowed the resultant polymer with well optical limiting properties for laser at wavelength 780 nm based on two-photon absorption mechanism.
A novel functional polyacetylene containing fluorene group as a pendant, poly (2-(p-methylstyrene)-7-acetylene-9, 9-dioctyl-fluorene), was synthesized in moderate yield by[Rh (nbd)Cl]2-Et3N catalyst. The structures and properties of monomer and polymer were characterized and evaluated with FTIR, NMR, UV-vis, GPC and Z-scan, respectively. The results show that the incorporation of fluorene into polyacetylene has endowed the resultant polymer with well optical limiting properties for laser at wavelength 780 nm based on two-photon absorption mechanism.
