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2001 Volume 12 Issue 9
2001, 12(9): 753-756
Abstract:
Isomerizaton of 4-amino-6-tert-butyl-3-methylthio-1, 2, 4-triazin-5 (4H)-one in the presence of base is described. Mechanism of this rearrangement reaction involving four-member ring intermediate formation has been proposed.
Isomerizaton of 4-amino-6-tert-butyl-3-methylthio-1, 2, 4-triazin-5 (4H)-one in the presence of base is described. Mechanism of this rearrangement reaction involving four-member ring intermediate formation has been proposed.
2001, 12(9): 757-760
Abstract:
The intramolecular hydrogen bond self-template effect was suggested in the process of directly synthesizing the first six chiral metal-free Robson-type macrocyclic ligands. These ligands were characterized by 1H NMR, IR, FAB-MS.
The intramolecular hydrogen bond self-template effect was suggested in the process of directly synthesizing the first six chiral metal-free Robson-type macrocyclic ligands. These ligands were characterized by 1H NMR, IR, FAB-MS.
2001, 12(9): 761-762
Abstract:
Amorphous poly (L-2-hydroxy-3-phenylpropanoic acid) (PLHPPA) was synthesized by the microwave-assisted polycondensation of L-2-hydroxy-3-phenylpropanoic acid (LHPPA). The weight average molar mass (Mw) of PLHPPA ranged from 3600 to 5300 and polydispersity index (Mw/Mn) from 1.0 to 1.4 when the reaction mixture was irradiated by microwave at 255, 340 and 510 w for 1 to 10 h, respectively.
Amorphous poly (L-2-hydroxy-3-phenylpropanoic acid) (PLHPPA) was synthesized by the microwave-assisted polycondensation of L-2-hydroxy-3-phenylpropanoic acid (LHPPA). The weight average molar mass (Mw) of PLHPPA ranged from 3600 to 5300 and polydispersity index (Mw/Mn) from 1.0 to 1.4 when the reaction mixture was irradiated by microwave at 255, 340 and 510 w for 1 to 10 h, respectively.
2001, 12(9): 763-764
Abstract:
Aryl azides and α-keto phosphorus ylides were reacted within 4~10 minutes with silica gel support, under microwave irridiation to afford corresponding l-aryl-l, 2, 3-triazoles in moderate to good yields.
Aryl azides and α-keto phosphorus ylides were reacted within 4~10 minutes with silica gel support, under microwave irridiation to afford corresponding l-aryl-l, 2, 3-triazoles in moderate to good yields.
2001, 12(9): 765-766
Abstract:
Two chiral building blocks 1 and 2 for anti-and syn-l, 3-diols has been achieved in 8steps and 7 steps respectively, starting from the readily available and inexpensive D (+)-xylose 3.
Two chiral building blocks 1 and 2 for anti-and syn-l, 3-diols has been achieved in 8steps and 7 steps respectively, starting from the readily available and inexpensive D (+)-xylose 3.
2001, 12(9): 767-768
Abstract:
A convenient method to synthesize (s)-(-)-benzyl-2-tert-butoxy carbonylamino-4-iodobutyrate from L-(+)methionine 1 was reported, the enantiomeric purity of the product was established by comparison of optical rotation data with literature values, indicating that the reaction process occurred without racemization.
A convenient method to synthesize (s)-(-)-benzyl-2-tert-butoxy carbonylamino-4-iodobutyrate from L-(+)methionine 1 was reported, the enantiomeric purity of the product was established by comparison of optical rotation data with literature values, indicating that the reaction process occurred without racemization.
2001, 12(9): 769-770
Abstract:
Synthesis of a series of chiral aza crown ethers ((S,S)-1, 5-bis (4-alkyl-5-hydroxy-2-oxo-3-azapentyl)-1, 5-diazacyclooctane) are described.
Synthesis of a series of chiral aza crown ethers ((S,S)-1, 5-bis (4-alkyl-5-hydroxy-2-oxo-3-azapentyl)-1, 5-diazacyclooctane) are described.
2001, 12(9): 771-774
Abstract:
Cleroindicin B, C and E, three new natural products originally isolated from Clerodendrum indicum, have been synthesized (in racemic forms for Cleroindicin C and E) by a facile route, starting from 2-(p-methoxy-phenyl) ethanol 1. The (±) cleroindicin C (5) has been resovled by the enantioselective inclusion methodology.
Cleroindicin B, C and E, three new natural products originally isolated from Clerodendrum indicum, have been synthesized (in racemic forms for Cleroindicin C and E) by a facile route, starting from 2-(p-methoxy-phenyl) ethanol 1. The (±) cleroindicin C (5) has been resovled by the enantioselective inclusion methodology.
2001, 12(9): 775-778
Abstract:
design, synthesis and in vivo evaluation of a new class of COX-2 inhibitors 3,4-diaryl-3-pyrrolin-2-ones are reported.
design, synthesis and in vivo evaluation of a new class of COX-2 inhibitors 3,4-diaryl-3-pyrrolin-2-ones are reported.
2001, 12(9): 779-782
Abstract:
Some novel lipids bearing nucleosides were designed and synthesized as gene vectors,and the structures of these compounds were characterized by UV, IR, 1HNMR, 13CNMR and elemental analysis.
Some novel lipids bearing nucleosides were designed and synthesized as gene vectors,and the structures of these compounds were characterized by UV, IR, 1HNMR, 13CNMR and elemental analysis.
2001, 12(9): 783-786
Abstract:
Semiempirical PM3 and density function theory B3LYP/3-2 1 g* calculations in vacuum and in water indicated that the "syn" orientation was preferred in the 1:2 complex of cucurbit[8]uril with protonated 2, 6-bis(4, 5-dihydro-lH-imidazol-2-yl)naphthalene. The π-π stacking interaction between the two substrate molecules was proposed as the physical origin of such a behavior.
Semiempirical PM3 and density function theory B3LYP/3-2 1 g* calculations in vacuum and in water indicated that the "syn" orientation was preferred in the 1:2 complex of cucurbit[8]uril with protonated 2, 6-bis(4, 5-dihydro-lH-imidazol-2-yl)naphthalene. The π-π stacking interaction between the two substrate molecules was proposed as the physical origin of such a behavior.
2001, 12(9): 787-790
Abstract:
Two new compounds, gonioquinone (1) and goniofufurone acetonide (2), have been isolated from the roots of Goniothalamus cheliensis Hu. Their structures were determined on the basis of spectral and chemical evidence.
Two new compounds, gonioquinone (1) and goniofufurone acetonide (2), have been isolated from the roots of Goniothalamus cheliensis Hu. Their structures were determined on the basis of spectral and chemical evidence.
2001, 12(9): 791-792
Abstract:
A New flavone named Macrophyllol was isolated from the roots of Uvaria macrophylla.The structure of 1 was elucidated on the basis of spectroscopic evidence.
A New flavone named Macrophyllol was isolated from the roots of Uvaria macrophylla.The structure of 1 was elucidated on the basis of spectroscopic evidence.
2001, 12(9): 793-796
Abstract:
A novel phenolic glucoside was isolated from stem barks of Alangium plantanifolium,its structure was elucidated to be 1-O-[2-(l-hydroxy-6-oxocyclohex-2-ene-l-carboxymcthyl)-phenyl]-4, 6-O-[(S)-4, 4', 5, 5', 6, 6'-hexahydroxydi-phenoyl]-β-D-glucopyranose 1 byspectroscopic methods including 2D NMR techniques.
A novel phenolic glucoside was isolated from stem barks of Alangium plantanifolium,its structure was elucidated to be 1-O-[2-(l-hydroxy-6-oxocyclohex-2-ene-l-carboxymcthyl)-phenyl]-4, 6-O-[(S)-4, 4', 5, 5', 6, 6'-hexahydroxydi-phenoyl]-β-D-glucopyranose 1 byspectroscopic methods including 2D NMR techniques.
2001, 12(9): 797-798
Abstract:
A new phytoecdysteroid was isolated from the root of Rhaponticum uniflorum. Its structure has been shown to be 2, 3, 20, 22-diacetonide ajugasterone.
A new phytoecdysteroid was isolated from the root of Rhaponticum uniflorum. Its structure has been shown to be 2, 3, 20, 22-diacetonide ajugasterone.
2001, 12(9): 799-802
Abstract:
Combined with flow-injection (Fl) technology, a simple chemiluminescence(CL)method was developed for hydrazine determination in this paper. It was found that hydrazine could greatly decrease the strong CL signal produced by the reaction between luminol and hexacyanoferrate (Ⅲ) in alkaline medium. The decreased CL intensity was linear with hydrazine concentration in the range of 5.0×10-9 gmL-1 to 4.0×10-5 gmL1, and the limit of detection was 2.0×10-9 g mL-1 (3Ó) with a relative standard deviation of 2.4~4.1% (n=5).
Combined with flow-injection (Fl) technology, a simple chemiluminescence(CL)method was developed for hydrazine determination in this paper. It was found that hydrazine could greatly decrease the strong CL signal produced by the reaction between luminol and hexacyanoferrate (Ⅲ) in alkaline medium. The decreased CL intensity was linear with hydrazine concentration in the range of 5.0×10-9 gmL-1 to 4.0×10-5 gmL1, and the limit of detection was 2.0×10-9 g mL-1 (3Ó) with a relative standard deviation of 2.4~4.1% (n=5).
2001, 12(9): 803-806
Abstract:
The cellulose tris (4-methylbenzoate) has been synthesised by the catalytic method and was supported at Gas Chrom Q. The absorption capability of cellulose tris (4-methylbenzoate)used as a gas chromatographic stationary phase was characterized by chromatographic method and the Clausius-Clapeyron equation. However, n-alcohols (C1-C8) were successfully separated on the column packed with Gas Chrom Q coated with cellullose tris (4-methylbenzoate).
The cellulose tris (4-methylbenzoate) has been synthesised by the catalytic method and was supported at Gas Chrom Q. The absorption capability of cellulose tris (4-methylbenzoate)used as a gas chromatographic stationary phase was characterized by chromatographic method and the Clausius-Clapeyron equation. However, n-alcohols (C1-C8) were successfully separated on the column packed with Gas Chrom Q coated with cellullose tris (4-methylbenzoate).
2001, 12(9): 807-808
Abstract:
It was found that phosphorylation of small peptide could improve the sensitivity in mass spectrometry. Density functional theory calculations showed that the energy for the protonation of N-(O, O'-dimethyl) phosphoryl glycylglycine is lower than that of glycylglycine. These could help to understanding the experimental results.
It was found that phosphorylation of small peptide could improve the sensitivity in mass spectrometry. Density functional theory calculations showed that the energy for the protonation of N-(O, O'-dimethyl) phosphoryl glycylglycine is lower than that of glycylglycine. These could help to understanding the experimental results.
2001, 12(9): 809-812
Abstract:
A multi-phase model was developed and Tb(Ⅲ) speciation in human blood plasma was studied. At a concentration below 3.744×10-4mol/L (or at the concentration), Tb(Ⅲ) is mostly bound to phosphate to form precipitate of TbPO4. As the concentration of Tb(Ⅲ) increases,phosphate is exceeded and another kind of precipitate of Tb2(CO3)3 appears. Among soluble Tb(Ⅲ) species, Tb(Ⅲ) mainly distribute in [Tb (Tf)] at low concentration and in [Tb (HSA)], [Tb2(Tf], [Tb (IgG)], [Tb (Lactate)]2+, [Tb (CitArgH)] and free Tb(Ⅲ) at high concentration.
A multi-phase model was developed and Tb(Ⅲ) speciation in human blood plasma was studied. At a concentration below 3.744×10-4mol/L (or at the concentration), Tb(Ⅲ) is mostly bound to phosphate to form precipitate of TbPO4. As the concentration of Tb(Ⅲ) increases,phosphate is exceeded and another kind of precipitate of Tb2(CO3)3 appears. Among soluble Tb(Ⅲ) species, Tb(Ⅲ) mainly distribute in [Tb (Tf)] at low concentration and in [Tb (HSA)], [Tb2(Tf], [Tb (IgG)], [Tb (Lactate)]2+, [Tb (CitArgH)] and free Tb(Ⅲ) at high concentration.
2001, 12(9): 813-814
Abstract:
We used whole-vacuolar patch-clamp recording mode to study the action mechanism of La3+ to Slow Vacuolar (SV) channels for the first time. We recorded SV channel currents of Xinlimei (Raphanus satirus L.) vacuolars. The minimum activation potentials of voltage-dependent SV channels lied in 25±5 mV. The increase in cytoplasmic Ca2+ led toenhancement of SV-type currents. It was found that the threshold potential of activation shifted towards more depolarized values whenever cytoplasmic Ca2+ was increased. When 10-10 mol/Lfree La3+ was added to the bath, SV-type current was suppressed by 60~75%. These data showed La3+ reduced ion permeabilities of Xinlimei root vacuolar membrane.
We used whole-vacuolar patch-clamp recording mode to study the action mechanism of La3+ to Slow Vacuolar (SV) channels for the first time. We recorded SV channel currents of Xinlimei (Raphanus satirus L.) vacuolars. The minimum activation potentials of voltage-dependent SV channels lied in 25±5 mV. The increase in cytoplasmic Ca2+ led toenhancement of SV-type currents. It was found that the threshold potential of activation shifted towards more depolarized values whenever cytoplasmic Ca2+ was increased. When 10-10 mol/Lfree La3+ was added to the bath, SV-type current was suppressed by 60~75%. These data showed La3+ reduced ion permeabilities of Xinlimei root vacuolar membrane.
2001, 12(9): 815-816
Abstract:
We determined whether La3+ enter human peripheral blood lymphocytes via Na+/Ca2+exchanger (measured with fura-2) We first compared the sensitivity of fura-2 with La3+ and Ca2+,the result indicates that the sensitiwty of fura-2 for La3+ is much greater than for Ca2+ . La3+ orms a 1:1 La3+-fura-2 complex (apparent dissociation constant=l.7%#215;l0-12mol/L, pH 7.05).Ouabain-pretreated cells, suspended in Na+-free medium, showed that La3+ can enter human lvmphocvtes via the Na+i/Ca2+ (La3+)o exchanger and is found to be about 10-12 mol/L in cells exp osed to 0.4 mmol/L La3+. Otherwise, the higher concentration (0.1 mmol/L) blocks theNa+i/Ca2+(La3+)o exchange-mediated influx of Ca2+, but the lower concentration (0.01 mmol/L)appears to increase Ca2+ entry.
We determined whether La3+ enter human peripheral blood lymphocytes via Na+/Ca2+exchanger (measured with fura-2) We first compared the sensitivity of fura-2 with La3+ and Ca2+,the result indicates that the sensitiwty of fura-2 for La3+ is much greater than for Ca2+ . La3+ orms a 1:1 La3+-fura-2 complex (apparent dissociation constant=l.7%#215;l0-12mol/L, pH 7.05).Ouabain-pretreated cells, suspended in Na+-free medium, showed that La3+ can enter human lvmphocvtes via the Na+i/Ca2+ (La3+)o exchanger and is found to be about 10-12 mol/L in cells exp osed to 0.4 mmol/L La3+. Otherwise, the higher concentration (0.1 mmol/L) blocks theNa+i/Ca2+(La3+)o exchange-mediated influx of Ca2+, but the lower concentration (0.01 mmol/L)appears to increase Ca2+ entry.
2001, 12(9): 817-820
Abstract:
The addition of a suitable amount of PPh3 to PdCI2 or PdCl2(PhCN)2 in situ canconsiderably increase the catalytic activity in the hydrogenation of nitrobenzene, while the catalytic activities of PdCI2 (reduced)＋PPh3, PdCI2(PPh3)2 and Pd(PPh3)4 are very poor. The poisoning of catalyst by mercury indicates that the catalytically active species are composed of Pd(0) colloidal particles. Transmission electron micrographs show that the size of nanometric Pd(0)particles of PdCI2 with PPh3 added in situ is smaller than that of PhCl2(PPh3) or PdC12(reduced)＋PPh3. A synergic effect of bimetallic catalysts such as PdCI2＋nPPh3＋NiCl2 (n=0.5, 1)and PdCl2(PhCN)2＋PPh3＋FeCI3 gives rise to a further increase in the catalytic activity.
The addition of a suitable amount of PPh3 to PdCI2 or PdCl2(PhCN)2 in situ canconsiderably increase the catalytic activity in the hydrogenation of nitrobenzene, while the catalytic activities of PdCI2 (reduced)＋PPh3, PdCI2(PPh3)2 and Pd(PPh3)4 are very poor. The poisoning of catalyst by mercury indicates that the catalytically active species are composed of Pd(0) colloidal particles. Transmission electron micrographs show that the size of nanometric Pd(0)particles of PdCI2 with PPh3 added in situ is smaller than that of PhCl2(PPh3) or PdC12(reduced)＋PPh3. A synergic effect of bimetallic catalysts such as PdCI2＋nPPh3＋NiCl2 (n=0.5, 1)and PdCl2(PhCN)2＋PPh3＋FeCI3 gives rise to a further increase in the catalytic activity.
2001, 12(9): 821-822
Abstract:
Samarocene complex was supported on a series of mesoporous silica with various pore sizes. Polymerization of methyl methacrylate (MMA) by these catalysts provide highly syndiotactic PMMAs with higher molecular weights compared with those obtained by solution polymerization with homogeneous catalyst system.
Samarocene complex was supported on a series of mesoporous silica with various pore sizes. Polymerization of methyl methacrylate (MMA) by these catalysts provide highly syndiotactic PMMAs with higher molecular weights compared with those obtained by solution polymerization with homogeneous catalyst system.
2001, 12(9): 823-926
Abstract:
The AIMCM-41 molecular sieves with two different pore sizes arc hydrothermally synthesized in the presence of surfactants with two different chain lengths. H-AIMCM-41 and Ru-Sn-B/H-AIMCM-41 which are prepared by the conventional ion-exchange and incipient wetness techniques of the AIMCM-41 show tair catalytic activity for esterification of glycerol by oleic acid and selective hydrogenation of oleic acid methylester, respectively.
The AIMCM-41 molecular sieves with two different pore sizes arc hydrothermally synthesized in the presence of surfactants with two different chain lengths. H-AIMCM-41 and Ru-Sn-B/H-AIMCM-41 which are prepared by the conventional ion-exchange and incipient wetness techniques of the AIMCM-41 show tair catalytic activity for esterification of glycerol by oleic acid and selective hydrogenation of oleic acid methylester, respectively.
2001, 12(9): 827-828
Abstract:
The effect of chromophores to the glass transition temperature of polyimide ensemble has been investigated by means of molecular dynamics simulation in conjunction with barrier analysis. Simulated Tg results indicated a good agreement with experimental value. This study showed the MD simulation could estimate the effect of chromophores to the Tg of polyimide ensemble conveniently and an estimation approach method had a surprising deviation of Tg from experiment. At the same time, a polyimide structure with higher barrier energy was designed and validated by MD simulation.
The effect of chromophores to the glass transition temperature of polyimide ensemble has been investigated by means of molecular dynamics simulation in conjunction with barrier analysis. Simulated Tg results indicated a good agreement with experimental value. This study showed the MD simulation could estimate the effect of chromophores to the Tg of polyimide ensemble conveniently and an estimation approach method had a surprising deviation of Tg from experiment. At the same time, a polyimide structure with higher barrier energy was designed and validated by MD simulation.
2001, 12(9): 829-832
Abstract:
In this study, the constant volume, visual method is used to measure thc critical point of CO2toluene, CO2＋cyclohexane, CO2＋n-butyraldehyde, CO2＋i-butyraldchyde, CO2＋methanol and CO2＋alcohol binary systems. The relationship between critical point and the concentration of the entrainer for different substances has been discussed, and the comparison of the phase behavior of single component system and that of binary systems have been carried out.
In this study, the constant volume, visual method is used to measure thc critical point of CO2toluene, CO2＋cyclohexane, CO2＋n-butyraldehyde, CO2＋i-butyraldchyde, CO2＋methanol and CO2＋alcohol binary systems. The relationship between critical point and the concentration of the entrainer for different substances has been discussed, and the comparison of the phase behavior of single component system and that of binary systems have been carried out.
2001, 12(9): 833-834
Abstract:
The chemical shift of 23Na in excimer NaXe was measured by using nuclear magnetic resonance (NMR) spectra, which is in good agreement with the theoretical value obtained by ab initio calculations. The bond length, dissociation energy, dipole of NaXe and Mulliken charges at Na and Xe in NaXe were calculated, respectively. The spectra of ultraviolet (UV) fluorescence and surface-enhanced Raman scattering of NaXe were also measured.
The chemical shift of 23Na in excimer NaXe was measured by using nuclear magnetic resonance (NMR) spectra, which is in good agreement with the theoretical value obtained by ab initio calculations. The bond length, dissociation energy, dipole of NaXe and Mulliken charges at Na and Xe in NaXe were calculated, respectively. The spectra of ultraviolet (UV) fluorescence and surface-enhanced Raman scattering of NaXe were also measured.
2001, 12(9): 835-838
Abstract:
A novel zirconium-based membrane material of BaCo0.4Fe0.4Zr0.2O3-ä with cubic perovskite structure was synthesized for the first time through a method of citric and EDTA acid combined complexes. The structural stability was characterized by XRD, O2-TPD and H2-TPR techniques respectively. The high oxygen permeation flux of 0.873 mL/cm2·min at 950℃ was obtained under He/Air gradient. Meanwhile, the single activation energy for oxygen permeation and the long-term steady operation of 200 h at 800℃ were achieved.
A novel zirconium-based membrane material of BaCo0.4Fe0.4Zr0.2O3-ä with cubic perovskite structure was synthesized for the first time through a method of citric and EDTA acid combined complexes. The structural stability was characterized by XRD, O2-TPD and H2-TPR techniques respectively. The high oxygen permeation flux of 0.873 mL/cm2·min at 950℃ was obtained under He/Air gradient. Meanwhile, the single activation energy for oxygen permeation and the long-term steady operation of 200 h at 800℃ were achieved.
2001, 12(9): 839-842
Abstract:
Carbon nanotubes (CNTs) of narrow size distribution can be abundantly produced in the catalytic decomposition of CH4 over pre-reduced LaNiO3, La4Ni3O10, La3Ni2O7 and La2NiO4.The CNTs obtained were characterized by means of transmission electron microscopy (TEM).Thermal oxidation of CNTs in air was monitored thermogravimetrically (TG). The resultsrevealed that a lower La/Ni ratio of the catalysts would lead to a wider diameter distribution and a higher degree of graphitic nature.
Carbon nanotubes (CNTs) of narrow size distribution can be abundantly produced in the catalytic decomposition of CH4 over pre-reduced LaNiO3, La4Ni3O10, La3Ni2O7 and La2NiO4.The CNTs obtained were characterized by means of transmission electron microscopy (TEM).Thermal oxidation of CNTs in air was monitored thermogravimetrically (TG). The resultsrevealed that a lower La/Ni ratio of the catalysts would lead to a wider diameter distribution and a higher degree of graphitic nature.
2001, 12(9): 843-846
Abstract:
Polyaniline (PANI) nanofibrils were prepared within the anodic aluminum oxide (AAO)template. The surface appearance of PAN1 nanofibrils and the structure of nanofibril array were observed by scanning electron microscopy (SEM). The diameter and the length of PANI nanofibrils are dependent on the pore diameter and the thickness of AAO template. X-rayphotoelectron spectroscopy (XPS) supplies the surface analysis confidence on the PANI nanofibrils.Fourier Transmission Infrared (FTIR) was used to confirm the fibrils composed of PANI.
Polyaniline (PANI) nanofibrils were prepared within the anodic aluminum oxide (AAO)template. The surface appearance of PAN1 nanofibrils and the structure of nanofibril array were observed by scanning electron microscopy (SEM). The diameter and the length of PANI nanofibrils are dependent on the pore diameter and the thickness of AAO template. X-rayphotoelectron spectroscopy (XPS) supplies the surface analysis confidence on the PANI nanofibrils.Fourier Transmission Infrared (FTIR) was used to confirm the fibrils composed of PANI.
