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2010 Volume 21 Issue 7
2010, 21(7): 761-764
doi: 10.1016/j.cclet.2010.02.014
Abstract:
Various xanthenes have been synthesized by the condensation of β-naphthol, 2-hydroxynaphthalene-1,4-dione or dimedone with various aldehydes in the presence of trifluoroacetic acid as catalyst in 1,1,3,3-N,N,N',N'-tetramethylguanidinium trifluoroacetate (TMGT) ionic liquid within 1h at 75℃.
Various xanthenes have been synthesized by the condensation of β-naphthol, 2-hydroxynaphthalene-1,4-dione or dimedone with various aldehydes in the presence of trifluoroacetic acid as catalyst in 1,1,3,3-N,N,N',N'-tetramethylguanidinium trifluoroacetate (TMGT) ionic liquid within 1h at 75℃.
2010, 21(7): 765-768
doi: 10.1016/j.cclet.2010.02.015
Abstract:
Penicillin G acylase (PGA) was immobilized on the magnetic hydrophilic polymer microspheres with average pore size of 17.1 nm, specific surface area of 128.2 m2/g and saturate magnetization of 6.4 emu/g. The 96.7% ampicillin yield with 1.60 of the synthesis/hydrolysis (S/H) ratio from 6-aminopenicillanic acid (6-APA) and D-(-)-alpha-phenylglycine methyl ester (D-PGME) can be achieved using the resultant magnetic biocatalyst in ethylene glycol, where only 82.1% yield with 1,40 of the S/H ratio was obtained using the free PGA under the identical reaction conditions. The immobilized PGA can be separated magnetically and recycled for five times without obvious loss of its catalytic activity.
Penicillin G acylase (PGA) was immobilized on the magnetic hydrophilic polymer microspheres with average pore size of 17.1 nm, specific surface area of 128.2 m2/g and saturate magnetization of 6.4 emu/g. The 96.7% ampicillin yield with 1.60 of the synthesis/hydrolysis (S/H) ratio from 6-aminopenicillanic acid (6-APA) and D-(-)-alpha-phenylglycine methyl ester (D-PGME) can be achieved using the resultant magnetic biocatalyst in ethylene glycol, where only 82.1% yield with 1,40 of the S/H ratio was obtained using the free PGA under the identical reaction conditions. The immobilized PGA can be separated magnetically and recycled for five times without obvious loss of its catalytic activity.
2010, 21(7): 769-773
doi: 10.1016/j.cclet.2010.03.037
Abstract:
In this article, a new 5-(p-maleicaminophenyl)-10,15,20-triphenylporphyrin (H2P) and relative zinc compound (ZnP) were synthesized and characterized by means of elemental analyses, UV-vis, IR, MS and 1H NMR spectroscopies. Furthermore, we have investigated the fluorescence spectroscopy of these compounds. The oxidation and reduction properties of the compounds were studied by the cyclic voltammetry, the oxidation-reduction potentials were obtained.
In this article, a new 5-(p-maleicaminophenyl)-10,15,20-triphenylporphyrin (H2P) and relative zinc compound (ZnP) were synthesized and characterized by means of elemental analyses, UV-vis, IR, MS and 1H NMR spectroscopies. Furthermore, we have investigated the fluorescence spectroscopy of these compounds. The oxidation and reduction properties of the compounds were studied by the cyclic voltammetry, the oxidation-reduction potentials were obtained.
2010, 21(7): 774-777
doi: 10.1016/j.cclet.2010.03.002
Abstract:
Vanadium-catalyzed oxidative kinetic resolution (OKR) of methyl o-chloromandelate 2a, key intermediate of the well-known oral antiplatelet agent (S)-clopidogrel, was achieved by ambient air for the first time. The air oxidation system, which was composed of vanadium and tridentate Schiff base ligands derived from amino alcohols and salicylaldehyde derivatives, afforded an efficient and economic approach to the target intermediate with high enantioselectivities (> 99% ee).
Vanadium-catalyzed oxidative kinetic resolution (OKR) of methyl o-chloromandelate 2a, key intermediate of the well-known oral antiplatelet agent (S)-clopidogrel, was achieved by ambient air for the first time. The air oxidation system, which was composed of vanadium and tridentate Schiff base ligands derived from amino alcohols and salicylaldehyde derivatives, afforded an efficient and economic approach to the target intermediate with high enantioselectivities (> 99% ee).
2010, 21(7): 778-781
doi: 10.1016/j.cclet.2010.03.022
Abstract:
Heteropoly acids efficiently catalyzed the cyclocondensation reaction of anthranilamide with aldehydes in water at ambient temperature and afforded the corresponding 2,3-dihydro-4 (1H)-quinazolinones compounds in good to excellent yields. This method provides mild reaction conditions and clean reaction profiles, using a small quantity of catalyst and a simple workup procedure.
Heteropoly acids efficiently catalyzed the cyclocondensation reaction of anthranilamide with aldehydes in water at ambient temperature and afforded the corresponding 2,3-dihydro-4 (1H)-quinazolinones compounds in good to excellent yields. This method provides mild reaction conditions and clean reaction profiles, using a small quantity of catalyst and a simple workup procedure.
2010, 21(7): 782-786
doi: 10.1016/j.cclet.2010.03.003
Abstract:
Quinazoline derivatives were synthesized from α-iminoesters via a cascade imino-Diels-Alder and then oxidation reaction catalyzed with CuBr2. This method provided a new strategy for preparing quinazoline derivatives which may be useful in the synthesis of heterocyclic intermediates.
Quinazoline derivatives were synthesized from α-iminoesters via a cascade imino-Diels-Alder and then oxidation reaction catalyzed with CuBr2. This method provided a new strategy for preparing quinazoline derivatives which may be useful in the synthesis of heterocyclic intermediates.
2010, 21(7): 787-789
doi: 10.1016/j.cclet.2010.03.023
Abstract:
The photochemical reaction of magnesium tetraphenyl porphyrin (MgTPP) with sulfur dioxide (SO2) was investigated in dichloromethane (CH2Cl2) by steady-state fluorescence, UV-vis absorption, MS, and XRD spectroscopic techniques. These spectra showed that under irradiation MgTPP reacted with SO2 to form 1:1 molecular adduct at first step. During the process of keeping irradiation and maintaining the flow of SO2, SO2 was reduced into S2- by MgTPP and the results were detected using MS and XRD techniques. Understanding the photochemical reaction of MgTPP with SO2 is of key interest in elucidating fundamental photochemical reaction mechanisms associated with this class of chlorophyll in the presence of SO2.
The photochemical reaction of magnesium tetraphenyl porphyrin (MgTPP) with sulfur dioxide (SO2) was investigated in dichloromethane (CH2Cl2) by steady-state fluorescence, UV-vis absorption, MS, and XRD spectroscopic techniques. These spectra showed that under irradiation MgTPP reacted with SO2 to form 1:1 molecular adduct at first step. During the process of keeping irradiation and maintaining the flow of SO2, SO2 was reduced into S2- by MgTPP and the results were detected using MS and XRD techniques. Understanding the photochemical reaction of MgTPP with SO2 is of key interest in elucidating fundamental photochemical reaction mechanisms associated with this class of chlorophyll in the presence of SO2.
P2O5 mediated rapid condensation of 2-aminothiophenol with aromatic aldehydes at ambient temperature
2010, 21(7): 790-793
doi: 10.1016/j.cclet.2010.03.006
Abstract:
2-Arylbenzothiazoles formed in good yields (65-90%) by the condensation of aminothiophenols with aromatic aldehydes using P2O5 at ambient temperature.
2-Arylbenzothiazoles formed in good yields (65-90%) by the condensation of aminothiophenols with aromatic aldehydes using P2O5 at ambient temperature.
2010, 21(7): 794-797
doi: 10.1016/j.cclet.2010.03.012
Abstract:
Sulfamic acid has been proved to be the most efficient and recyclable catalyst in carbamate synthesis from alkylamine and dialkyl carbonate. High selectivity, cost-efficiency and simple product separation were the advantageous features obtained in this process. Sulfamic acid could be reused several times and keep its initial activity in the recycle runs. In addition, sulfamic acid has also exhibited the potential catalytic ability for alkylation of aromatic amines.
Sulfamic acid has been proved to be the most efficient and recyclable catalyst in carbamate synthesis from alkylamine and dialkyl carbonate. High selectivity, cost-efficiency and simple product separation were the advantageous features obtained in this process. Sulfamic acid could be reused several times and keep its initial activity in the recycle runs. In addition, sulfamic acid has also exhibited the potential catalytic ability for alkylation of aromatic amines.
2010, 21(7): 798-801
doi: 10.1016/j.cclet.2010.02.020
Abstract:
The building block of N-alkyl derivative of allosamidin (chitinase inhibitor), 4,6-O-benzylidene-N-octyl-D-allosamine hydro-chloride was stereoselectively synthesized in two steps under mild conditions. Nucleophilic addition of octylamine to 2-oxoglucopyranoside gave a ‘carbonyl group transfer’ product in 62% yield. Subsequent stereoselective reduction of newly formed C=O with NaBH4 produced title compound in 75% yield. X-ray diffraction analysis indicates the title compound adopts syn 1,2,3 stereochemistry and chair-chair conformation. The crystal structure is stabilized by hydrogen bonds.
The building block of N-alkyl derivative of allosamidin (chitinase inhibitor), 4,6-O-benzylidene-N-octyl-D-allosamine hydro-chloride was stereoselectively synthesized in two steps under mild conditions. Nucleophilic addition of octylamine to 2-oxoglucopyranoside gave a ‘carbonyl group transfer’ product in 62% yield. Subsequent stereoselective reduction of newly formed C=O with NaBH4 produced title compound in 75% yield. X-ray diffraction analysis indicates the title compound adopts syn 1,2,3 stereochemistry and chair-chair conformation. The crystal structure is stabilized by hydrogen bonds.
2010, 21(7): 802-806
doi: 10.1016/j.cclet.2010.03.011
Abstract:
A chiral ruthenium complex [(1S,2S)-DPEN]-RuCl2 (PPh3)2 (DPEN=1,2-diphenylethylenediamine, PPh3=triphenylphosph-ine) was encapsulated in the channel of Al-MCM-41 by electrostatic adsorption and 1,1-dichlorosilacyclobutane modification. The prepared heterogeneous catalyst showed the same catalytic activity and enantioselectivity as the corresponding homogeneous catalyst in the asymmetric hydrogenation of acetophenone, and could be reused at least seven times without significant loss of catalytic activity and enantioselectivity.
A chiral ruthenium complex [(1S,2S)-DPEN]-RuCl2 (PPh3)2 (DPEN=1,2-diphenylethylenediamine, PPh3=triphenylphosph-ine) was encapsulated in the channel of Al-MCM-41 by electrostatic adsorption and 1,1-dichlorosilacyclobutane modification. The prepared heterogeneous catalyst showed the same catalytic activity and enantioselectivity as the corresponding homogeneous catalyst in the asymmetric hydrogenation of acetophenone, and could be reused at least seven times without significant loss of catalytic activity and enantioselectivity.
2010, 21(7): 807-809
doi: 10.1016/j.cclet.2010.02.023
Abstract:
A novel series of calix [4]azacrown derivatives with the reaction between calix [4]azacrown and the different fluorophore derivatives, which may be useful fluorescent receptors, have been synthesized and structurally characterized by IR, 1H NMR, 13C NMR and MS. From their analysis data, it was found those compounds adopted a cone conformation.
A novel series of calix [4]azacrown derivatives with the reaction between calix [4]azacrown and the different fluorophore derivatives, which may be useful fluorescent receptors, have been synthesized and structurally characterized by IR, 1H NMR, 13C NMR and MS. From their analysis data, it was found those compounds adopted a cone conformation.
2010, 21(7): 810-812
doi: 10.1016/j.cclet.2010.03.035
Abstract:
A novel organophosphorus compound containing the structure of both β-amino acid and B-aminophosphonate is designed and synthesized. Arbuzov reaction with P(OEt)3, the N-Boc protected iodide 3 cannot provide the desired product but 2-oxazolidinone 4 because of the neighboring-group participation of the Boc moiety.To avoid the intramolecular participation of the carbamates, the Ts protecting group is employed and the Ts-protected iodide 5 affords the target product successfully.
A novel organophosphorus compound containing the structure of both β-amino acid and B-aminophosphonate is designed and synthesized. Arbuzov reaction with P(OEt)3, the N-Boc protected iodide 3 cannot provide the desired product but 2-oxazolidinone 4 because of the neighboring-group participation of the Boc moiety.To avoid the intramolecular participation of the carbamates, the Ts protecting group is employed and the Ts-protected iodide 5 affords the target product successfully.
2010, 21(7): 813-815
doi: 10.1016/j.cclet.2010.02.024
Abstract:
sSeveral bisabolane sesquiterpenes, (±)-curcumene, (±)-curcuphenol, (±)-curcudiol and (±)-curcuhydroquinone, have been synthesized in racemic form and fully characterized. The salient characteristic of our approach is that a Johnson-Claisen arrangement was involved as a key step.
sSeveral bisabolane sesquiterpenes, (±)-curcumene, (±)-curcuphenol, (±)-curcudiol and (±)-curcuhydroquinone, have been synthesized in racemic form and fully characterized. The salient characteristic of our approach is that a Johnson-Claisen arrangement was involved as a key step.
2010, 21(7): 816-817
doi: 10.1016/j.cclet.2010.03.020
Abstract:
A new compound, 9,10-dihydrophenanthrinic acid, 9,10-dione-3,4-methylenedioxy-8-methoxy (1) was isolated from the roots of Peucedanum praeruptorum Dunn on the basis of spectral evidences.
A new compound, 9,10-dihydrophenanthrinic acid, 9,10-dione-3,4-methylenedioxy-8-methoxy (1) was isolated from the roots of Peucedanum praeruptorum Dunn on the basis of spectral evidences.
2010, 21(7): 818-820
doi: 10.1016/j.cclet.2010.03.021
Abstract:
Two new chalcones, β,2',4',5'-tetramethoxychalcone 1, and β,2',5'-trimethoxyfurano [4",5":3',4']-chalcone 2 were obtained from an ethyl acetate-soluble fraction of ethanol extract of the stem of Fordia cauliflora. Their chemical structures were determined by analysis of spectroscopic evidences.
Two new chalcones, β,2',4',5'-tetramethoxychalcone 1, and β,2',5'-trimethoxyfurano [4",5":3',4']-chalcone 2 were obtained from an ethyl acetate-soluble fraction of ethanol extract of the stem of Fordia cauliflora. Their chemical structures were determined by analysis of spectroscopic evidences.
2010, 21(7): 821-823
doi: 10.1016/j.cclet.2010.02.016
Abstract:
A new alkylene dihydrofuran glycoside (1) was isolated from the root bark of Morus alba L., along with moracin M-3'-O-β-D-glucopyranoside (2), and moracin M-6,3'-di-O-β-D-glucopyranoside (3). Compound 1 was identified as 2-methylene-3-methoxy-2, 5-dihydrofuran-4-O-β-D-glucopyranoside on the basis of chemical and spectroscopic data including ID and 2D NMR spectral analysis. In addition, the antioxidant activity of 1 was evaluated using the l,l-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay. The IC50 values were 2.49 and 0.45 mg/mL, respectively.
A new alkylene dihydrofuran glycoside (1) was isolated from the root bark of Morus alba L., along with moracin M-3'-O-β-D-glucopyranoside (2), and moracin M-6,3'-di-O-β-D-glucopyranoside (3). Compound 1 was identified as 2-methylene-3-methoxy-2, 5-dihydrofuran-4-O-β-D-glucopyranoside on the basis of chemical and spectroscopic data including ID and 2D NMR spectral analysis. In addition, the antioxidant activity of 1 was evaluated using the l,l-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay. The IC50 values were 2.49 and 0.45 mg/mL, respectively.
2010, 21(7): 824-826
doi: 10.1016/j.cclet.2010.02.019
Abstract:
Three new aspochalsins (R-T) (1-3) were isolated from the marine-derived fungus Spicaria elegans. Their structures were elucidated on the basis of comprehensive spectral analysis including 1D and 2D NMR techniques, and HR-ESI-MS.
Three new aspochalsins (R-T) (1-3) were isolated from the marine-derived fungus Spicaria elegans. Their structures were elucidated on the basis of comprehensive spectral analysis including 1D and 2D NMR techniques, and HR-ESI-MS.
2010, 21(7): 827-829
doi: 10.1016/j.cclet.2010.03.007
Abstract:
Two new terpenes,wilfornine H (1)and triptobenzene Q (2)were isolated from Tripterygium wilfordii,as well as 11 terpenes.Their structures were elucidated by spectroscopic methods.Compounds 5,9-13 shewed significant immunosuppressive activities.
Two new terpenes,wilfornine H (1)and triptobenzene Q (2)were isolated from Tripterygium wilfordii,as well as 11 terpenes.Their structures were elucidated by spectroscopic methods.Compounds 5,9-13 shewed significant immunosuppressive activities.
2010, 21(7): 830-833
doi: 10.1016/j.cclet.2010.02.021
Abstract:
Three new sesquiterpene alkaloids,1-desaeetylwilforgine (1),1-desaeetylwilforine (2),and 9'-hydroxy-2-nicotinoylwilforine (3)were isolated from the roots of Tripterygium wilfordii Hook f.,along with six known alkaloids.Their structures were established on the basis of spectral analysis.
Three new sesquiterpene alkaloids,1-desaeetylwilforgine (1),1-desaeetylwilforine (2),and 9'-hydroxy-2-nicotinoylwilforine (3)were isolated from the roots of Tripterygium wilfordii Hook f.,along with six known alkaloids.Their structures were established on the basis of spectral analysis.
2010, 21(7): 834-837
doi: 10.1016/j.cclet.2010.02.022
Abstract:
A new derivative of triterpene named Erigeronol 1 was isolated from the EtOH extract of the aerial part of Conyza canadensis together with 15 known compounds for the first time from this plant.The structure of Erigeronol 1 was elucidated as 3-O-(hydroxyacetyl)-23,28-dihydroxy-β-amyrin by hydrolysis and spectroscopic analysis.Erigeronol 1 showed potent cytotoxic activity with IC50 value of 7.77±0.47 μg/mL against melanoma B16 determined by the 3-(4,5-dimethylthiazo-2-yl)-2,5-dipbenyltetrazolium bromide(MTT)method.
A new derivative of triterpene named Erigeronol 1 was isolated from the EtOH extract of the aerial part of Conyza canadensis together with 15 known compounds for the first time from this plant.The structure of Erigeronol 1 was elucidated as 3-O-(hydroxyacetyl)-23,28-dihydroxy-β-amyrin by hydrolysis and spectroscopic analysis.Erigeronol 1 showed potent cytotoxic activity with IC50 value of 7.77±0.47 μg/mL against melanoma B16 determined by the 3-(4,5-dimethylthiazo-2-yl)-2,5-dipbenyltetrazolium bromide(MTT)method.
2010, 21(7): 838-841
doi: 10.1016/j.cclet.2010.02.018
Abstract:
Two new limonoids,1α-tigloyloxy-3α-acetoxyl-7α-hydroxyl-12α-ethoxyl nimbolinin (1)and 1α-benzoyloxy-3α-acetoxyl-7α-hydroxyl-12α-ethoxyl nimbolinin (2),were isolated from the fruits of Melia toosendan.Their structures were established on the basis of various NMR spectroscopic analyses,including 2D-NMR techniques (HSQC,HMBC,NOESY)and HR-ESI-MS.
Two new limonoids,1α-tigloyloxy-3α-acetoxyl-7α-hydroxyl-12α-ethoxyl nimbolinin (1)and 1α-benzoyloxy-3α-acetoxyl-7α-hydroxyl-12α-ethoxyl nimbolinin (2),were isolated from the fruits of Melia toosendan.Their structures were established on the basis of various NMR spectroscopic analyses,including 2D-NMR techniques (HSQC,HMBC,NOESY)and HR-ESI-MS.
2010, 21(7): 842-845
doi: 10.1016/j.cclet.2010.03.024
Abstract:
A new naphthoquinone compound named 7-hydroxyl-8-methoxyltrypethelone 3 together with two known compounds trypethelone 1 and trypethelone methyl ether 2 was isolated from cultured mycobiunt of Astrothelium sp.The structures were elucidated by 1D and 2D NMR spectroscopic analysis as well as comparison with those reported in literatures.Compound 1 displayed significant antibacterial activity against Bacillus subtilis (ATCC 6633),and showed modest antibacterial activity against Staphylococcus aureus col (MRSA) (CGMCC 1.2465),while compounds 2 and 3 showed modest antibacterial activity against Enterococcus faecalis 850E (CGMCC 1.2135)and S.aureus col (MRSA) (CGMCC 1.2465).
A new naphthoquinone compound named 7-hydroxyl-8-methoxyltrypethelone 3 together with two known compounds trypethelone 1 and trypethelone methyl ether 2 was isolated from cultured mycobiunt of Astrothelium sp.The structures were elucidated by 1D and 2D NMR spectroscopic analysis as well as comparison with those reported in literatures.Compound 1 displayed significant antibacterial activity against Bacillus subtilis (ATCC 6633),and showed modest antibacterial activity against Staphylococcus aureus col (MRSA) (CGMCC 1.2465),while compounds 2 and 3 showed modest antibacterial activity against Enterococcus faecalis 850E (CGMCC 1.2135)and S.aureus col (MRSA) (CGMCC 1.2465).
2010, 21(7): 846-849
doi: 10.1016/j.cclet.2010.03.034
Abstract:
A new 5α-adynerin-type cardenolide,named funingenoside U (1),together with its aglycone,(17R)-3β-hydroxy-4β-acetoxy-8,14β-epoxy-5α-card-20 (22)-enolide,was isolated from the roots of Parepigynum funingense.Their structures were established on the basis of spectral (MS,1D and 2D NMR) measurements and chemical evidences.
A new 5α-adynerin-type cardenolide,named funingenoside U (1),together with its aglycone,(17R)-3β-hydroxy-4β-acetoxy-8,14β-epoxy-5α-card-20 (22)-enolide,was isolated from the roots of Parepigynum funingense.Their structures were established on the basis of spectral (MS,1D and 2D NMR) measurements and chemical evidences.
2010, 21(7): 850-852
doi: 10.1016/j.cclet.2010.03.026
Abstract:
A new polyacetylene glycoside, (1,3Z,11E)-tridecatriene-7,9-diyne-5-hydroxyl-6-O-β-D-glucopyranoside,was isolated from the rhizomes of Atractylodes lancea (Thunb.)DC.Its structure was elucidated on the basis of spectral analysis.
A new polyacetylene glycoside, (1,3Z,11E)-tridecatriene-7,9-diyne-5-hydroxyl-6-O-β-D-glucopyranoside,was isolated from the rhizomes of Atractylodes lancea (Thunb.)DC.Its structure was elucidated on the basis of spectral analysis.
2010, 21(7): 853-855
doi: 10.1016/j.cclet.2010.02.017
Abstract:
Tolylene-2,4-diisocyanate (2,4-TDI)1 reacts with methanol through two simultaneous paths in the polyurethane reaction,which involve two different intermediates-tolylene-4-caxbamatic-2-isocyanate 2 and tolylene-2-carbamatic-4-isocyanate 3,and the final product is tolylene-2,4-dicarbamate 4.The-CH3 chemical shifts in benzene ring in compounds 1,2,3 and 4 can be easily tested and well distinguished,through which those four compounds are quantified and their kinetics are investigated.It shows that four rate constants for the tolylene-2,4-diisocyanate-methanol reaction in CCl4 at 50℃ are k1=9.6×10-2h-2mol-2min-1,k2=1.4×10-2h-2mol-2min-l,k3=4.0×10-3h-2mol-2min-1,k4=1.4×10-3h-2mol-2min-1.(k1 is the reaction rate constant from compounds 1 to 2; k2 is the reaction rate constant from compounds 1 to 3; k3 is the reaction rate constant from compounds 3 to 4; k4 is the reaction rate constant from compounds 2 to 4).
Tolylene-2,4-diisocyanate (2,4-TDI)1 reacts with methanol through two simultaneous paths in the polyurethane reaction,which involve two different intermediates-tolylene-4-caxbamatic-2-isocyanate 2 and tolylene-2-carbamatic-4-isocyanate 3,and the final product is tolylene-2,4-dicarbamate 4.The-CH3 chemical shifts in benzene ring in compounds 1,2,3 and 4 can be easily tested and well distinguished,through which those four compounds are quantified and their kinetics are investigated.It shows that four rate constants for the tolylene-2,4-diisocyanate-methanol reaction in CCl4 at 50℃ are k1=9.6×10-2h-2mol-2min-1,k2=1.4×10-2h-2mol-2min-l,k3=4.0×10-3h-2mol-2min-1,k4=1.4×10-3h-2mol-2min-1.(k1 is the reaction rate constant from compounds 1 to 2; k2 is the reaction rate constant from compounds 1 to 3; k3 is the reaction rate constant from compounds 3 to 4; k4 is the reaction rate constant from compounds 2 to 4).
2010, 21(7): 856-859
doi: 10.1016/j.cclet.2010.01.025
Abstract:
It was found that 20 amino acids could inhibit the intensity of the luminol-H2O2-CuSO4 chemiluminescence system.Using this character,a rapid and sensitive method for the determination of 20 amino acids was developed with flow injection coupled with chemiluminescence detection.Under the optimal conditions,the detection limits of 20 amino acids were in the range of 4.5×10-7-4.3×10-10 mol/L,and the relative standard deviations were less than 3.2%.The proposed method was successfully applied to drug analysis.The possible mechanism was also discussed.
It was found that 20 amino acids could inhibit the intensity of the luminol-H2O2-CuSO4 chemiluminescence system.Using this character,a rapid and sensitive method for the determination of 20 amino acids was developed with flow injection coupled with chemiluminescence detection.Under the optimal conditions,the detection limits of 20 amino acids were in the range of 4.5×10-7-4.3×10-10 mol/L,and the relative standard deviations were less than 3.2%.The proposed method was successfully applied to drug analysis.The possible mechanism was also discussed.
2010, 21(7): 860-863
doi: 10.1016/j.cclet.2010.01.024
Abstract:
A method of high performance liquid chromatographic separation of clausenamide enantiomers with chiral-AGP (α1-acid glycoprotein)stationary phases has been established.The absolute configurations of (-)clausenamide and (+)clausenamide are 3S,4R,5R,6S and 3R,4S,5S,6R,respectively.The present method has been used to analyze the (-) clausenamide and (+) clausenamide and its analogues such as the major metabolite and synthetic derivatives of clansenamide.
A method of high performance liquid chromatographic separation of clausenamide enantiomers with chiral-AGP (α1-acid glycoprotein)stationary phases has been established.The absolute configurations of (-)clausenamide and (+)clausenamide are 3S,4R,5R,6S and 3R,4S,5S,6R,respectively.The present method has been used to analyze the (-) clausenamide and (+) clausenamide and its analogues such as the major metabolite and synthetic derivatives of clansenamide.
2010, 21(7): 864-867
doi: 10.1016/j.cclet.2010.01.039
Abstract:
The triple-shelled hollow spheres with optical properties were prepared via reversible addition-fragmentation chain transfer (RAFT)polymerization.After removal the core templates of the poly (styrene),the hollow silica spheres were obtained.The coating process of poly (methyl methacrylate) (PMMA)on the hollow silica spheres surface via surface RAFT polymerization was performed subsequently.The polymers coated on the hollow spheres surfaces were end-functionalized by trithiocarbonate,and they were used as RAFT agent to proceed the chain extension polymerization using Tb complex as monomer.The samples were characterized by FT-IR,SEM and luminescence spectroscopy respectively.The results indicated that the triple-shelled hollow spheres had been prepared successfully and the average diameter of the hollow core was about 1 μm.
The triple-shelled hollow spheres with optical properties were prepared via reversible addition-fragmentation chain transfer (RAFT)polymerization.After removal the core templates of the poly (styrene),the hollow silica spheres were obtained.The coating process of poly (methyl methacrylate) (PMMA)on the hollow silica spheres surface via surface RAFT polymerization was performed subsequently.The polymers coated on the hollow spheres surfaces were end-functionalized by trithiocarbonate,and they were used as RAFT agent to proceed the chain extension polymerization using Tb complex as monomer.The samples were characterized by FT-IR,SEM and luminescence spectroscopy respectively.The results indicated that the triple-shelled hollow spheres had been prepared successfully and the average diameter of the hollow core was about 1 μm.
2010, 21(7): 868-871
doi: 10.1016/j.cclet.2010.01.007
Abstract:
A novel benzoxazine-based phenolic resin containing furan groups (PFB)was synthesized via simple two-step reactions and the structure of PFB was confirmed by FTIR and 1H NMR spectra.Differential scanning calorimetry (DSC)showed that the polybenzoxazine cured from PFB had good heat resistance and lower polymerization temperature compared with that of benzoxazine-hased phenolic resins.
A novel benzoxazine-based phenolic resin containing furan groups (PFB)was synthesized via simple two-step reactions and the structure of PFB was confirmed by FTIR and 1H NMR spectra.Differential scanning calorimetry (DSC)showed that the polybenzoxazine cured from PFB had good heat resistance and lower polymerization temperature compared with that of benzoxazine-hased phenolic resins.
2010, 21(7): 872-875
doi: 10.1016/j.cclet.2010.01.036
Abstract:
Silver nanorods have been successfully synthesized in large scale by the ethylene glycol (EG) reduction in the presence of ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) and polyvinyl-pyrrolidone (PVP).The silver nanorods were characterized by scanning electron microscopy (SEM),high-resolution transmission electron microscopy (HRTEM),transmission electron microscopy (TEM),electron energy disperse spectroscopy (EDS) and UV-vis spectroscopy.The results showed that the uniform silver nanorods have an average diameter of about 100 nm and the aspect ratio from 15 to 20.IL,bmimBF4 may play a role of capping agent together with PVP in the formation of silver nanorods.On the other hand,bmimBF4 may accelerate nucleation and improve the stability of the resulting Ag nanorods due to the low interface tension of IL.
Silver nanorods have been successfully synthesized in large scale by the ethylene glycol (EG) reduction in the presence of ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) and polyvinyl-pyrrolidone (PVP).The silver nanorods were characterized by scanning electron microscopy (SEM),high-resolution transmission electron microscopy (HRTEM),transmission electron microscopy (TEM),electron energy disperse spectroscopy (EDS) and UV-vis spectroscopy.The results showed that the uniform silver nanorods have an average diameter of about 100 nm and the aspect ratio from 15 to 20.IL,bmimBF4 may play a role of capping agent together with PVP in the formation of silver nanorods.On the other hand,bmimBF4 may accelerate nucleation and improve the stability of the resulting Ag nanorods due to the low interface tension of IL.
2010, 21(7): 876-879
doi: 10.1016/j.cclet.2010.02.003
Abstract:
The layer-by-layer (LBL) selfassembly of anionic and cationic multi-walled carbon nanotubes (MWNTs) through electrostatic interaction has been carried out to fabricate all-MWNT multilayer films.The alternate uniform assembly of anionic and cationic MWNTs was investigated by UV-vis spectroscopy.Scanning electron microscopy (SEM) images displayed the growth of the MWNT films.
The layer-by-layer (LBL) selfassembly of anionic and cationic multi-walled carbon nanotubes (MWNTs) through electrostatic interaction has been carried out to fabricate all-MWNT multilayer films.The alternate uniform assembly of anionic and cationic MWNTs was investigated by UV-vis spectroscopy.Scanning electron microscopy (SEM) images displayed the growth of the MWNT films.
2010, 21(7): 880-883
doi: 10.1016/j.cclet.2010.01.029
Abstract:
Generally,a microemulsion consists of oil,water,surfactant and sometimes cosurfactant.Herein,we report a novel surfactantfree microemulsion (denoted as SFME) composed of benzene,water and ethanol without the amphiphilic molecular structure of traditional surfactant.The phase behavior of the ternary system was investigated,finding that there were a single-phase region and a two-phase region in ternary phase diagram.The electrical conductivity measurement was employed to investigate the microregion of the single-phase region,and a bicontinuous microregion and a benzene-in-water (O/W) microemulsion microregion were identified,which was confirmed by freeze-fracture transmission electron microscopy (FF-TEM) observations.The sizes of the microemulsion droplets are in the range of 20-50 nm.
Generally,a microemulsion consists of oil,water,surfactant and sometimes cosurfactant.Herein,we report a novel surfactantfree microemulsion (denoted as SFME) composed of benzene,water and ethanol without the amphiphilic molecular structure of traditional surfactant.The phase behavior of the ternary system was investigated,finding that there were a single-phase region and a two-phase region in ternary phase diagram.The electrical conductivity measurement was employed to investigate the microregion of the single-phase region,and a bicontinuous microregion and a benzene-in-water (O/W) microemulsion microregion were identified,which was confirmed by freeze-fracture transmission electron microscopy (FF-TEM) observations.The sizes of the microemulsion droplets are in the range of 20-50 nm.
2010, 21(7): 884-887
doi: 10.1016/j.cclet.2010.01.005
Abstract:
Polypyrrole/polyvinylalcohol (PPy/PVA) foam was prepared by direct foam polymerization in water and then it was coated on the indium-tin oxide transparent conductive glass (ITO) to form conventional three-electrode cell.FTIR and UV-vis spectra were adopted to characterize the molecular structure and the absorption spectra of foam material,respectively.The porous structure of PPy/PVA foams and their photoelectric conversion behaviors were studied.The dimension of the pores is bigger than 100 μm in diameter.Compared with the smooth film,the Voc and Isc of the foam film enhanced by 1.58-fold and 5.59-fold,respectively.
Polypyrrole/polyvinylalcohol (PPy/PVA) foam was prepared by direct foam polymerization in water and then it was coated on the indium-tin oxide transparent conductive glass (ITO) to form conventional three-electrode cell.FTIR and UV-vis spectra were adopted to characterize the molecular structure and the absorption spectra of foam material,respectively.The porous structure of PPy/PVA foams and their photoelectric conversion behaviors were studied.The dimension of the pores is bigger than 100 μm in diameter.Compared with the smooth film,the Voc and Isc of the foam film enhanced by 1.58-fold and 5.59-fold,respectively.
