Login In
2011 Volume 22 Issue 5
2011, 22(5): 505-507
doi: 10.1016/j.cclet.2010.11.023
Abstract:
(3S,4R)-Bengamide E (2) was synthesized starting from D-glucono-δ-lactone (3) and the key deoxygenation step from13to15was achieved by the application of NaBH3CN and ZnI2.Compared with natural bengamide E (1), the synthetic compound (3S,4R)-bengamide E (2) was inactive against the cell growth of HUVEC and cancer cells.These data represent the significance of the stereochemistry at C-3 and C-4 of bengamides for structural recognition and binding with the target(s).
(3S,4R)-Bengamide E (2) was synthesized starting from D-glucono-δ-lactone (3) and the key deoxygenation step from13to15was achieved by the application of NaBH3CN and ZnI2.Compared with natural bengamide E (1), the synthetic compound (3S,4R)-bengamide E (2) was inactive against the cell growth of HUVEC and cancer cells.These data represent the significance of the stereochemistry at C-3 and C-4 of bengamides for structural recognition and binding with the target(s).
2011, 22(5): 508-510
doi: 10.1016/j.cclet.2010.12.013
Abstract:
A series of l,2,4-triazolo [3,4-b]-thiadiazoles were synthesized following microwave irradiation method and also by conventional method.Newly synthesized compounds were evaluated for their anti-inflammatory and analgesic activities.
A series of l,2,4-triazolo [3,4-b]-thiadiazoles were synthesized following microwave irradiation method and also by conventional method.Newly synthesized compounds were evaluated for their anti-inflammatory and analgesic activities.
2011, 22(5): 511-514
doi: 10.1016/j.cclet.2010.11.019
Abstract:
A new method for preparation of N-tosylimines by InCl3-mediated condensation of aldehydes with p-toluenesulfonamide in refluxing benzene is reported.The procedure is lauded by its simplicity, mild reaction conditions, excellent yields and adaptability to electron deficient and electron rich aromatic, and α,β-unsaturated aldehydes.
A new method for preparation of N-tosylimines by InCl3-mediated condensation of aldehydes with p-toluenesulfonamide in refluxing benzene is reported.The procedure is lauded by its simplicity, mild reaction conditions, excellent yields and adaptability to electron deficient and electron rich aromatic, and α,β-unsaturated aldehydes.
2011, 22(5): 515-518
doi: 10.1016/j.cclet.2010.11.026
Abstract:
An efficient synthetic method for bis (indol-3-yl) alkane derivatives has been developed.In the presence of 5 mol% of pyridinium tribromide (PTB), the condensation of indoles and aldehydes proceeded smoothly under mild conditions, giving rise to the corresponding bis (indol-3-yl) alkanes in good to excellent yields.
An efficient synthetic method for bis (indol-3-yl) alkane derivatives has been developed.In the presence of 5 mol% of pyridinium tribromide (PTB), the condensation of indoles and aldehydes proceeded smoothly under mild conditions, giving rise to the corresponding bis (indol-3-yl) alkanes in good to excellent yields.
2011, 22(5): 519-522
doi: 10.1016/j.cclet.2010.11.029
Abstract:
Based on the active site of lanosterol 14α-demethylase of azole antifungal agents, sixteen l-(lH-l,2,4-triazole-l-yl)-2-(2,4-difluorophenyl)-3-(N-n-butyl-N-l-substitutedbenzyl-4-methylene-lH-l,2,3-triazole)-2-propanols have been designed, synthesized and evaluated as antifungal agents.Results of preliminary antifungal tests against eight human pathogenic fungi in vitro showed that some of the compounds exhibited excellent activities with broad spectrum.
Based on the active site of lanosterol 14α-demethylase of azole antifungal agents, sixteen l-(lH-l,2,4-triazole-l-yl)-2-(2,4-difluorophenyl)-3-(N-n-butyl-N-l-substitutedbenzyl-4-methylene-lH-l,2,3-triazole)-2-propanols have been designed, synthesized and evaluated as antifungal agents.Results of preliminary antifungal tests against eight human pathogenic fungi in vitro showed that some of the compounds exhibited excellent activities with broad spectrum.
2011, 22(5): 523-526
doi: 10.1016/j.cclet.2010.11.030
Abstract:
An improved and scalable process for substituted 3,8-diazabicyclo [3.2.1]octane was developed.N-Benzyl-2,5-dicarbethoxy-pyrrolidine 2 was reduced to N-benzyl-2,5-dihydroxymethylpyrrolidine 9 and subsequently debenzylated to afford N-Boc-2,5-dihydroxymethylpyrrolidine 10.After mesylation of the diol 10 and cyclization with benzylamine, a diversity of scaffold, 3,8-diazabicyclo [3.2.1]octane analogue 12 was obtained in a total yield of 42% in five steps.
An improved and scalable process for substituted 3,8-diazabicyclo [3.2.1]octane was developed.N-Benzyl-2,5-dicarbethoxy-pyrrolidine 2 was reduced to N-benzyl-2,5-dihydroxymethylpyrrolidine 9 and subsequently debenzylated to afford N-Boc-2,5-dihydroxymethylpyrrolidine 10.After mesylation of the diol 10 and cyclization with benzylamine, a diversity of scaffold, 3,8-diazabicyclo [3.2.1]octane analogue 12 was obtained in a total yield of 42% in five steps.
2011, 22(5): 527-530
doi: 10.1016/j.cclet.2010.12.011
Abstract:
A novel thiol-derivative porphyrin [2,7,12,18-tetramethyl-13,17-di(3-disulfidepropyl)porphyrin] bearing the symmetrical disulphide bond and its metal complexes have been successfully prepared by means of modification on naturally easily derived heme.The results are described by MS-MS and UV-vis spectroscopy.
A novel thiol-derivative porphyrin [2,7,12,18-tetramethyl-13,17-di(3-disulfidepropyl)porphyrin] bearing the symmetrical disulphide bond and its metal complexes have been successfully prepared by means of modification on naturally easily derived heme.The results are described by MS-MS and UV-vis spectroscopy.
2011, 22(5): 531-534
doi: 10.1016/j.cclet.2010.12.012
Abstract:
Multicomponent synthesis of mono and bis 4-substituted-l,4-dihydropyridines from aldehydes, dimedone and ammonium acetate in the presence of an efficient recyclable catalyst, L-proline, in high yield and short reaction time is reported.
Multicomponent synthesis of mono and bis 4-substituted-l,4-dihydropyridines from aldehydes, dimedone and ammonium acetate in the presence of an efficient recyclable catalyst, L-proline, in high yield and short reaction time is reported.
2011, 22(5): 535-538
doi: 10.1016/j.cclet.2010.12.001
Abstract:
A facile method for the synthesis of a new series of R,R-2-(4-(2-(4-(5-chloro-3-halopyridin-2-yloxy)-phenoxy)-propionyloxy)-phenoxy)-propionic acid ester derivatives containing a halo-substituted pyridine carrying two R,R chiral centers from (R)-2-(4-hydroxyphenoxy)propionic acid, halopyridines and alcohols using base/cyanuric chloride/catalyst system is reported.Their herbicidal activities against grass weeds and crops selectivity were evaluated.
A facile method for the synthesis of a new series of R,R-2-(4-(2-(4-(5-chloro-3-halopyridin-2-yloxy)-phenoxy)-propionyloxy)-phenoxy)-propionic acid ester derivatives containing a halo-substituted pyridine carrying two R,R chiral centers from (R)-2-(4-hydroxyphenoxy)propionic acid, halopyridines and alcohols using base/cyanuric chloride/catalyst system is reported.Their herbicidal activities against grass weeds and crops selectivity were evaluated.
2011, 22(5): 539-542
doi: 10.1016/j.cclet.2010.11.031
Abstract:
One novel porphyrin p-Q2 is planned to be synthesized by condensation between ATPP and Q1.However, after separation by chromatography and characterization with IR, 1H NMR, HR-MS and X-ray, p-Q1 is obtained unexpectedly.Compared the structure of p-Q1 with that of p-Q2, it is realized that an intramolecular cyclization rearrangement takes place when the azo group is situated in the o-position to the amido group.This rearrangement offers a new way to prepare indazole heterocycle.In addition, the spectral properties of p-Q1 have been studied by UV-vis and steady state fluorescence spectroscopy.Strong fluorescence quenching is observed in the preliminary emission spectrum due to the proposed electron transfer from the excited porphyrin to the anthraquinone moieties.
One novel porphyrin p-Q2 is planned to be synthesized by condensation between ATPP and Q1.However, after separation by chromatography and characterization with IR, 1H NMR, HR-MS and X-ray, p-Q1 is obtained unexpectedly.Compared the structure of p-Q1 with that of p-Q2, it is realized that an intramolecular cyclization rearrangement takes place when the azo group is situated in the o-position to the amido group.This rearrangement offers a new way to prepare indazole heterocycle.In addition, the spectral properties of p-Q1 have been studied by UV-vis and steady state fluorescence spectroscopy.Strong fluorescence quenching is observed in the preliminary emission spectrum due to the proposed electron transfer from the excited porphyrin to the anthraquinone moieties.
2011, 22(5): 543-546
doi: 10.1016/j.cclet.2010.12.002
Abstract:
A simple, efficient, and general method has been developed for the synthesis of α-amino nitriles.Oxalic acid as a Brønsted acid promotes the addition of TMSCN to various imines (generated in situ).
A simple, efficient, and general method has been developed for the synthesis of α-amino nitriles.Oxalic acid as a Brønsted acid promotes the addition of TMSCN to various imines (generated in situ).
2011, 22(5): 547-550
doi: 10.1016/j.cclet.2010.11.017
Abstract:
Nanomaterials are considered as suitable heterogeneous catalysts for many organic reactions.Herein nano-tube TiO2 has been reported as a heterogeneous catalyst, for synthesis of imines in sunlight at room temperature under solvent-free conditions.The condensation of less electrophilic carbonyl compounds with poorly nucleophilic amines was afforded imines in excellent yields.
Nanomaterials are considered as suitable heterogeneous catalysts for many organic reactions.Herein nano-tube TiO2 has been reported as a heterogeneous catalyst, for synthesis of imines in sunlight at room temperature under solvent-free conditions.The condensation of less electrophilic carbonyl compounds with poorly nucleophilic amines was afforded imines in excellent yields.
2011, 22(5): 551-554
doi: 10.1016/j.cclet.2010.11.018
Abstract:
Amidoalkyl naphthols have been synthesized in high yields in the presence of 1-hexanesulphonic acid sodium salt as an inexpensive solid catalyst under solvent-free conditions and microwave-irradiation.This catalyst provides clean conversion|greater selectivity and easy workup make this protocol practical and economically attractive.
Amidoalkyl naphthols have been synthesized in high yields in the presence of 1-hexanesulphonic acid sodium salt as an inexpensive solid catalyst under solvent-free conditions and microwave-irradiation.This catalyst provides clean conversion|greater selectivity and easy workup make this protocol practical and economically attractive.
2011, 22(5): 555-558
doi: 10.1016/j.cclet.2010.12.003
Abstract:
A simple and efficient method has been developed for the synthesis of α-amino nitriles from aldehydes, amines and trimethylsilyl cyanide (Me3 SiCN) in the presence of a catalytic amount of cyanuric acid at room temperature.
A simple and efficient method has been developed for the synthesis of α-amino nitriles from aldehydes, amines and trimethylsilyl cyanide (Me3 SiCN) in the presence of a catalytic amount of cyanuric acid at room temperature.
2011, 22(5): 559-562
doi: 10.1016/j.cclet.2010.11.034
Abstract:
A simple, efficient, and general method has been developed for the one-pot, three-component synthesis of α-aminophosphonates from condensation reaction of trimethyl phosphite, aryl aldehydes and aryl amines in the presence of CoCl2·6H2O under solvent-free conditions.Thus α-aminophosphonates were synthesized relatively quickly in good yields at room temperature.
A simple, efficient, and general method has been developed for the one-pot, three-component synthesis of α-aminophosphonates from condensation reaction of trimethyl phosphite, aryl aldehydes and aryl amines in the presence of CoCl2·6H2O under solvent-free conditions.Thus α-aminophosphonates were synthesized relatively quickly in good yields at room temperature.
2011, 22(5): 563-566
doi: 10.1016/j.cclet.2010.11.021
Abstract:
An efficient synthesis of novel α-aminophosphonates by the reaction of aldehydes and amines with triethyl phosphite in the presence of the easily available, inexpensive, and nontoxic catalyst thiamine hydrochloride (VB1).This method affords the α-aminophosphonates under the influence of ultrasound irradiation in aqueous medium, in short reaction times (4-6 min), high yields(85-95%), with improved purity.The process is green, mild, inexpensive and excellent yields are the main compensation of this procedure.
An efficient synthesis of novel α-aminophosphonates by the reaction of aldehydes and amines with triethyl phosphite in the presence of the easily available, inexpensive, and nontoxic catalyst thiamine hydrochloride (VB1).This method affords the α-aminophosphonates under the influence of ultrasound irradiation in aqueous medium, in short reaction times (4-6 min), high yields(85-95%), with improved purity.The process is green, mild, inexpensive and excellent yields are the main compensation of this procedure.
2011, 22(5): 567-570
doi: 10.1016/j.cclet.2010.10.055
Abstract:
A series of new methyl-4-((substituted phenyl)[6H-indolo(2,3-b)quinoxalin-6yllmethylamino) benzoate derivatives have been synthesized and assayed for their antibacterial activity on 9 different bacterial strains.Among the screened compounds 2e-2g exhibited potent inhibitory activity compared to standard drug employed, worth further investigation.
A series of new methyl-4-((substituted phenyl)[6H-indolo(2,3-b)quinoxalin-6yllmethylamino) benzoate derivatives have been synthesized and assayed for their antibacterial activity on 9 different bacterial strains.Among the screened compounds 2e-2g exhibited potent inhibitory activity compared to standard drug employed, worth further investigation.
2011, 22(5): 571-574
doi: 10.1016/j.cclet.2010.11.022
Abstract:
A novel and convenient iron-catalyzed ketonization of 2-aryl-1,1-dibromoalkenes with KOAc has been achieved.A series of α-acetoxy aryl ketones were prepared with moderate yields via 2-carbon position functionalization of 2-aryl-1,1-dibromoalkenes.
A novel and convenient iron-catalyzed ketonization of 2-aryl-1,1-dibromoalkenes with KOAc has been achieved.A series of α-acetoxy aryl ketones were prepared with moderate yields via 2-carbon position functionalization of 2-aryl-1,1-dibromoalkenes.
2011, 22(5): 575-579
doi: 10.1016/j.cclet.2010.11.027
Abstract:
An unusual oleanane triterpene (1) was isolated from aerial parts of Rhododendron campanulatum.The compound had shown prominent antibacterial and immunomodulatory activities.The structure of the compound was determined by spectroscopic data including ID and 2D NMR spectral analysis.
An unusual oleanane triterpene (1) was isolated from aerial parts of Rhododendron campanulatum.The compound had shown prominent antibacterial and immunomodulatory activities.The structure of the compound was determined by spectroscopic data including ID and 2D NMR spectral analysis.
2011, 22(5): 580-582
doi: 10.1016/j.cclet.2010.12.015
Abstract:
Two new diterpenoids, 3,4,18 β-cyclopropa-ent-abieta-8(14),13(15)-dien-16,12-olide (1) and 3-oxojolkinolide B (2), were isolated from the roots of Suregada glomerulata(Blume)Baill.Their structures were determined by spectroscopic evidences.Compound 2 showed moderate cytotoxicity.
Two new diterpenoids, 3,4,18 β-cyclopropa-ent-abieta-8(14),13(15)-dien-16,12-olide (1) and 3-oxojolkinolide B (2), were isolated from the roots of Suregada glomerulata(Blume)Baill.Their structures were determined by spectroscopic evidences.Compound 2 showed moderate cytotoxicity.
2011, 22(5): 583-586
doi: 10.1016/j.cclet.2010.11.033
Abstract:
Two new cucurbitane-type triterpenoids,(23E)-5 β,19-epoxycucurbita-6,23,25-triene-3β-ol(1)and(19R, 23E)-5β,19-epoxy-19-ethoxycucurbita-6,23-diene-3 β,25-diol(2), together with three known compounds, have been isolated from the fruit of Momordica charantia L.Their structures were determined on the basis of spectral analysis.Their cytotoxic activity was tested on 5 cancer cell lines, MCF-7, HepG2, Dul45, Colon205 and HL-60 by MTT assay.Compounds 1, 3 and 4 showed weak cytotoxicity.
Two new cucurbitane-type triterpenoids,(23E)-5 β,19-epoxycucurbita-6,23,25-triene-3β-ol(1)and(19R, 23E)-5β,19-epoxy-19-ethoxycucurbita-6,23-diene-3 β,25-diol(2), together with three known compounds, have been isolated from the fruit of Momordica charantia L.Their structures were determined on the basis of spectral analysis.Their cytotoxic activity was tested on 5 cancer cell lines, MCF-7, HepG2, Dul45, Colon205 and HL-60 by MTT assay.Compounds 1, 3 and 4 showed weak cytotoxicity.
2011, 22(5): 587-590
doi: 10.1016/j.cclet.2010.11.032
Abstract:
The formation of charge transfer complex between iodine with 4'-nitrobenzo-15-crown-5(NB15C5)and benzo-15-crowN-5(B15C5)is investigated spectrophotometrically in chloroform and dichloromethane(DCM)solutions at 25℃.The pseudo-first-order rate constants for the transformation process were evaluated from the absorbance-time data and found to vary in the order of DCM > CHCl3.The values of the formation constant, Kf, for each complex are evaluated from Benesi-Hilebrand equation.Stability of the resulting complex in two solvents was also found to vary in the order of DCM > CHC13.
The formation of charge transfer complex between iodine with 4'-nitrobenzo-15-crown-5(NB15C5)and benzo-15-crowN-5(B15C5)is investigated spectrophotometrically in chloroform and dichloromethane(DCM)solutions at 25℃.The pseudo-first-order rate constants for the transformation process were evaluated from the absorbance-time data and found to vary in the order of DCM > CHCl3.The values of the formation constant, Kf, for each complex are evaluated from Benesi-Hilebrand equation.Stability of the resulting complex in two solvents was also found to vary in the order of DCM > CHC13.
2011, 22(5): 591-594
doi: 10.1016/j.cclet.2010.12.014
Abstract:
The voltammetric behaviour of three 5-nitroimidazoles, metronidazole, tinidazole and ornidazole, was investigated, and a method was developed for the simultaneous determination of these compounds, based on their reduction at a hanging mercury drop electrode(HMDE)in pH 8.95 buffer with differential pulse voltammetric(DPV)approach.Well defined voltammetric waves with peak potentials of-692,-640 and-652 mV were observed for these compounds, respectively.It is difficult to determine them individually from their mixtures without preseparation, for their voltammetric peaks overlapped seriously, so the chemometrics were used to resolve the overlapped voltammogram and quantify the mixtures.The proposed method was successfully applied to the determination of three 5-nitroimidazoles in milk and honey samples.
The voltammetric behaviour of three 5-nitroimidazoles, metronidazole, tinidazole and ornidazole, was investigated, and a method was developed for the simultaneous determination of these compounds, based on their reduction at a hanging mercury drop electrode(HMDE)in pH 8.95 buffer with differential pulse voltammetric(DPV)approach.Well defined voltammetric waves with peak potentials of-692,-640 and-652 mV were observed for these compounds, respectively.It is difficult to determine them individually from their mixtures without preseparation, for their voltammetric peaks overlapped seriously, so the chemometrics were used to resolve the overlapped voltammogram and quantify the mixtures.The proposed method was successfully applied to the determination of three 5-nitroimidazoles in milk and honey samples.
2011, 22(5): 595-598
doi: 10.1016/j.cclet.2010.10.054
Abstract:
A simple, rapid and sensitive method has been described for the determination of the trace amounts of bromide.The method is based on the catalytic effect of bromide ion on the oxidation of methylene blue by bromate in sulfuric acid media.The reaction is monitored spectrophotometrically by measuring the decrease in the absorbance of methylene blue at 665 nm.Bromide was determined in the range of 0.05-1.90 μg/mL with the detection limit of 0.03 μg/mL.The relative standard deviations of five replicate determinations of 0.20 and 10.0 μg/mL of bromide were 2.4% and 1.8%, respectively.The influence of potential interfering ions and substances was studied.The method is applied to the analysis of bromide in clidinium-c tablet as a real sample.
A simple, rapid and sensitive method has been described for the determination of the trace amounts of bromide.The method is based on the catalytic effect of bromide ion on the oxidation of methylene blue by bromate in sulfuric acid media.The reaction is monitored spectrophotometrically by measuring the decrease in the absorbance of methylene blue at 665 nm.Bromide was determined in the range of 0.05-1.90 μg/mL with the detection limit of 0.03 μg/mL.The relative standard deviations of five replicate determinations of 0.20 and 10.0 μg/mL of bromide were 2.4% and 1.8%, respectively.The influence of potential interfering ions and substances was studied.The method is applied to the analysis of bromide in clidinium-c tablet as a real sample.
2011, 22(5): 599-602
doi: 10.1016/j.cclet.2010.10.053
Abstract:
A new 1,3,4-oxadiazole compound with a dimesitylboryl group was synthesized and characterized by 1H NMR.MS, element analysis and X-ray single-crystal diffraction.It exhibits good blue emission at 425 nm and high sensitivity to fluoride anion.
A new 1,3,4-oxadiazole compound with a dimesitylboryl group was synthesized and characterized by 1H NMR.MS, element analysis and X-ray single-crystal diffraction.It exhibits good blue emission at 425 nm and high sensitivity to fluoride anion.
2011, 22(5): 603-606
doi: 10.1016/j.cclet.2010.11.020
Abstract:
In this paper, the TiO2 nanotubes were synthesized by hydrothermal method usinga 10 mol/LNaOH aqueous solution at 150℃.The structure of prepared materials was characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), scanning electron microscope(SEM)and Brunauer-Emmett-Teller(BET).The prepared TiO2 nanotubes were used to prepare thick film gas sensors and the gas sensing properties to various gases were tested.Results show the prepared TiO2 nanotube gas sensors responses to ethanol under dry condition at 450℃.This could be attributed to the fact that it had high porous morphology and a higher pore volume, which can promote the diffusion of ethanol deep inside the films and improve the sensor response.Moreover, the gas sensor made with nanotubes exhibit high selective response towards ethanol gas compared with H2, CO, acetone.
In this paper, the TiO2 nanotubes were synthesized by hydrothermal method usinga 10 mol/LNaOH aqueous solution at 150℃.The structure of prepared materials was characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), scanning electron microscope(SEM)and Brunauer-Emmett-Teller(BET).The prepared TiO2 nanotubes were used to prepare thick film gas sensors and the gas sensing properties to various gases were tested.Results show the prepared TiO2 nanotube gas sensors responses to ethanol under dry condition at 450℃.This could be attributed to the fact that it had high porous morphology and a higher pore volume, which can promote the diffusion of ethanol deep inside the films and improve the sensor response.Moreover, the gas sensor made with nanotubes exhibit high selective response towards ethanol gas compared with H2, CO, acetone.
2011, 22(5): 607-610
doi: 10.1016/j.cclet.2010.11.016
Abstract:
L-Lysine hydrochloride was transformed to ethyl L-lysine dihydrochloride.This salt was reacted with trimellitic anhydride to yield the corresponding diacid(1).Interfacial polycondensation results novel poly(ester-imide)s(PEIa-i).These polymers have inherent viscosities in the range of 0.23-0.47 dl g-1, display optical activity, and are readily soluble in polar aprotic solvents.They start to decompose(T10%)above 350℃ and display glass-transition temperatures at 100.42-172.81℃.All of the above polymers were fully characterized by UV, FT-IR and 1H NMR spectroscopy, elemental analysis, TGA, DSC, inherent viscosity measurement and specific rotation.
L-Lysine hydrochloride was transformed to ethyl L-lysine dihydrochloride.This salt was reacted with trimellitic anhydride to yield the corresponding diacid(1).Interfacial polycondensation results novel poly(ester-imide)s(PEIa-i).These polymers have inherent viscosities in the range of 0.23-0.47 dl g-1, display optical activity, and are readily soluble in polar aprotic solvents.They start to decompose(T10%)above 350℃ and display glass-transition temperatures at 100.42-172.81℃.All of the above polymers were fully characterized by UV, FT-IR and 1H NMR spectroscopy, elemental analysis, TGA, DSC, inherent viscosity measurement and specific rotation.
2011, 22(5): 611-614
doi: 10.1016/j.cclet.2010.12.004
Abstract:
Hydrophilic molecularly imprinted polymers(MIPs)were prepared using tetracycline as template, methacrylic acid as monomer and glycidilmethacrylate as pro-hydrophilic co-monomer.Compared with common MIPs, the imprinting effect and adsorption amounts of hydrophilic MIPs for tetracycline(TC)were greatly improved in water media.Furthermore, the electrochemical sensor fabricated by modifying hydrophilic MIPs on glassy carbon electrode was developed for the determination of TC in foodstuff samples.
Hydrophilic molecularly imprinted polymers(MIPs)were prepared using tetracycline as template, methacrylic acid as monomer and glycidilmethacrylate as pro-hydrophilic co-monomer.Compared with common MIPs, the imprinting effect and adsorption amounts of hydrophilic MIPs for tetracycline(TC)were greatly improved in water media.Furthermore, the electrochemical sensor fabricated by modifying hydrophilic MIPs on glassy carbon electrode was developed for the determination of TC in foodstuff samples.
2011, 22(5): 615-618
doi: 10.1016/j.cclet.2010.12.010
Abstract:
Multi-cyclic CaO carbonation/calcination is an attractive method for CO2 capture during coal combustion. However, the capture capacity of CaO sharply decreases with increasing carbonation/calcination cycles. In order to improve the stability of CO2 capture capacity of CaO during carbonation/calcination cycles, synthetic CaO/Al2O3 sorbents were synthesized by two methods: wet chemistry and sol-gel-combustion-synthesis(SGCS)to make a further comparison. The results indicate that the SGCS-made CaO/ Al2O3=80:20 wt% sorbent provides a competitive performance of a capture capacity of 0.43 g-CO2/g-sorbent after 20 cycles.
Multi-cyclic CaO carbonation/calcination is an attractive method for CO2 capture during coal combustion. However, the capture capacity of CaO sharply decreases with increasing carbonation/calcination cycles. In order to improve the stability of CO2 capture capacity of CaO during carbonation/calcination cycles, synthetic CaO/Al2O3 sorbents were synthesized by two methods: wet chemistry and sol-gel-combustion-synthesis(SGCS)to make a further comparison. The results indicate that the SGCS-made CaO/ Al2O3=80:20 wt% sorbent provides a competitive performance of a capture capacity of 0.43 g-CO2/g-sorbent after 20 cycles.
2011, 22(5): 619-622
doi: 10.1016/j.cclet.2010.10.042
Abstract:
The design and synthesis of new calamitic benzothiazole-based liquid crystals, 2-[4-(4-alkyloxybenzoyloxy)-phenyI]ben-zothiazoles are presented.The target compound was characterized using spectroscopic techniques, such as FT-IR, NMR(1H and 13C), microanalysis and EI-MS.The liquid crystalline behaviours of these compounds were thoroughly examined by differential scanning calorimetry and polarizing optical microscope techniques.These materials exhibited enantiotropic nematic phase with high thermal stability(> 168℃).Smectic A phase starts to emerge as monotropic(metastable)phase from C10 member and changes into enantiotropic(stable)phase from C12 and persists up to C16 members.
The design and synthesis of new calamitic benzothiazole-based liquid crystals, 2-[4-(4-alkyloxybenzoyloxy)-phenyI]ben-zothiazoles are presented.The target compound was characterized using spectroscopic techniques, such as FT-IR, NMR(1H and 13C), microanalysis and EI-MS.The liquid crystalline behaviours of these compounds were thoroughly examined by differential scanning calorimetry and polarizing optical microscope techniques.These materials exhibited enantiotropic nematic phase with high thermal stability(> 168℃).Smectic A phase starts to emerge as monotropic(metastable)phase from C10 member and changes into enantiotropic(stable)phase from C12 and persists up to C16 members.
2011, 22(5): 623-625
doi: 10.1016/j.cclet.2010.11.028
Abstract:
A thermodynamic study on the interaction of myelin basic protein with mercury ion was studied by using isothermal titration calorimetry, ITC, at 300.15, 310.15 and 320.15 K in Tris buffer solution at pH 7.The enthalpies of MBP+Hg2+ interaction are reported and analysed in terms of the extended solvation model.It was found that MBP has two identical and non-cooperative binding sites for Hg2+ ions.The intrinsic dissociation equilibrium constants are 99.904,112.968 and 126.724 μmol/L, and the molar enthalpy of binding are-11.634,-10.768 and-10.117 kJ mol -1 at 300.15, 310.15 and 320.15 K, respectively.
A thermodynamic study on the interaction of myelin basic protein with mercury ion was studied by using isothermal titration calorimetry, ITC, at 300.15, 310.15 and 320.15 K in Tris buffer solution at pH 7.The enthalpies of MBP+Hg2+ interaction are reported and analysed in terms of the extended solvation model.It was found that MBP has two identical and non-cooperative binding sites for Hg2+ ions.The intrinsic dissociation equilibrium constants are 99.904,112.968 and 126.724 μmol/L, and the molar enthalpy of binding are-11.634,-10.768 and-10.117 kJ mol -1 at 300.15, 310.15 and 320.15 K, respectively.
2011, 22(5): 626-630
doi: 10.1016/j.cclet.2010.11.006
Abstract:
By means of a stochastic model suggested in this paper for the systems with local non-equilibrium excited thermal fluctuations, the famous Shannon entropy is extended to include the heat conduction processes controlled externally by boundary constraints of constant temperature gradients at two sides.Meanwhile, using the description of master equation for the continuous Markov processes a balance equation of stochastic entropy production valid for one dimension gaseous heat conduction systems with high values of Prandtl number has been also established.Based on it, a general expression for both the stochastic entropy production and the entropy production of fluctuations have been further deduced by the Ω-expansions.In this formalism, all kinds of stochastic contributions to the dissipation from the non-equilibrium thermal fluctuation and internal noise turn explicit.
By means of a stochastic model suggested in this paper for the systems with local non-equilibrium excited thermal fluctuations, the famous Shannon entropy is extended to include the heat conduction processes controlled externally by boundary constraints of constant temperature gradients at two sides.Meanwhile, using the description of master equation for the continuous Markov processes a balance equation of stochastic entropy production valid for one dimension gaseous heat conduction systems with high values of Prandtl number has been also established.Based on it, a general expression for both the stochastic entropy production and the entropy production of fluctuations have been further deduced by the Ω-expansions.In this formalism, all kinds of stochastic contributions to the dissipation from the non-equilibrium thermal fluctuation and internal noise turn explicit.
