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1999 Volume 10 Issue 1
1999, 10(1): 1-4
Abstract:
A new method to synthesize heterocycle-fused troponoid compounds by oxidizing azocoupling products of 3-isopropenyltropolone and 3-cinnamoyItropolone with bromine in the presence of pyridine was reported for the first time. Reaction of azo-couping products of 3-isopropenyl tropolone la~f and 3-cinnamoyltropoIone 3a-d with excess bromine afforded heterocycle-fused troponoid compounds 2a-f, 4a-d, respectively.
A new method to synthesize heterocycle-fused troponoid compounds by oxidizing azocoupling products of 3-isopropenyltropolone and 3-cinnamoyItropolone with bromine in the presence of pyridine was reported for the first time. Reaction of azo-couping products of 3-isopropenyl tropolone la~f and 3-cinnamoyltropoIone 3a-d with excess bromine afforded heterocycle-fused troponoid compounds 2a-f, 4a-d, respectively.
1999, 10(1): 5-6
Abstract:
The title compounds 3 and 4 condensed with aromatic aldehydes to give α-aroyl-α-cinnamoyl ketene cyclic dithioacetals 5 and 6 with sodium ethoxide as the base. The stereochemistry of 5 and 6 was assigned as E-configuration by lH NMR.
The title compounds 3 and 4 condensed with aromatic aldehydes to give α-aroyl-α-cinnamoyl ketene cyclic dithioacetals 5 and 6 with sodium ethoxide as the base. The stereochemistry of 5 and 6 was assigned as E-configuration by lH NMR.
1999, 10(1): 7-8
Abstract:
The reduction of disulfides by samarium diiodide led to sa arium thiolates (ArSSmI2). This new thiolate anion species reacted smoothly with α, β -unsaturated esters (nitriles) to give 1, 4-addition products β -thioesters and β -thionitriles in good yields under mild and neutral condition.
The reduction of disulfides by samarium diiodide led to sa arium thiolates (ArSSmI2). This new thiolate anion species reacted smoothly with α, β -unsaturated esters (nitriles) to give 1, 4-addition products β -thioesters and β -thionitriles in good yields under mild and neutral condition.
1999, 10(1): 9-10
Abstract:
Adducts of Schiff bases and acyl chlorides react with allylsamarium bromide to afford the corresponding tertiary amides.
Adducts of Schiff bases and acyl chlorides react with allylsamarium bromide to afford the corresponding tertiary amides.
1999, 10(1): 11-12
Abstract:
Acyldesilylation of 5-trimethylsilyl-2-furancarboxaldehyde with acyl chlorides was investigated and the unexpected 5-acyl-2-dichloromethylfuran were obtained as main products. The expected 5-acyl-2-furancarboxaldehydes were also found after hydrolyzing of the corresponding dichloro-compounds.
Acyldesilylation of 5-trimethylsilyl-2-furancarboxaldehyde with acyl chlorides was investigated and the unexpected 5-acyl-2-dichloromethylfuran were obtained as main products. The expected 5-acyl-2-furancarboxaldehydes were also found after hydrolyzing of the corresponding dichloro-compounds.
1999, 10(1): 13-14
Abstract:
A novel nucleophilic substitution of pyridazines is found, in which phenoxy group is dislodged rather than the halogen atom, on treating 3-haIo-6-phenoxypyridazines with alkoxy anion. The reactivity of substituents on benzene ring and the halogen atom of pyridazines are studied. Reasonable explanation based on the quantum chemical calculations are given.
A novel nucleophilic substitution of pyridazines is found, in which phenoxy group is dislodged rather than the halogen atom, on treating 3-haIo-6-phenoxypyridazines with alkoxy anion. The reactivity of substituents on benzene ring and the halogen atom of pyridazines are studied. Reasonable explanation based on the quantum chemical calculations are given.
1999, 10(1): 15-16
Abstract:
Two new long-chain spirobenzopyrans and their crowned derivatives were designed and synthesized.
Two new long-chain spirobenzopyrans and their crowned derivatives were designed and synthesized.
1999, 10(1): 17-18
Abstract:
Functionalized organozinc reagents can easily under 1, 4-addition reaction with unsaturated esters in the presence of catalytic amount of Ni (acac)2 and tertiary amines under very mild conditions to give the products in excellent yields.
Functionalized organozinc reagents can easily under 1, 4-addition reaction with unsaturated esters in the presence of catalytic amount of Ni (acac)2 and tertiary amines under very mild conditions to give the products in excellent yields.
1999, 10(1): 19-20
Abstract:
β-Ketosulfoxides were synthesized by the reaction of acetone with aryl sulfinate esters in the presence of hydrochloric acid and the structure of title compounds were finally confirmed by IR, 1HNMR and 13CNMR spectra.
β-Ketosulfoxides were synthesized by the reaction of acetone with aryl sulfinate esters in the presence of hydrochloric acid and the structure of title compounds were finally confirmed by IR, 1HNMR and 13CNMR spectra.
1999, 10(1): 21-22
Abstract:
The synthesis of 3-(2'-hydroxybutyl) isobenzofuran-1 (3H)-one 1 from phthalic anhydride via the intermediate 3-(2'-oxoethyl) isobenzofuran-1 (3H)-one 6 was described.
The synthesis of 3-(2'-hydroxybutyl) isobenzofuran-1 (3H)-one 1 from phthalic anhydride via the intermediate 3-(2'-oxoethyl) isobenzofuran-1 (3H)-one 6 was described.
1999, 10(1): 23-26
Abstract:
1, 5-Benzothiazepines 1 react with phenylacetyl chloride to give the title compounds. The structures of these new compounds were confirmed by elemental analysis, 1H NMR, l3C NMR and MS spectroscopy, and their configuration (the mutual positions of the substituents relative to the β-lactam ring) and conformation of the compounds were determined by X-ray crystal analysis.
1, 5-Benzothiazepines 1 react with phenylacetyl chloride to give the title compounds. The structures of these new compounds were confirmed by elemental analysis, 1H NMR, l3C NMR and MS spectroscopy, and their configuration (the mutual positions of the substituents relative to the β-lactam ring) and conformation of the compounds were determined by X-ray crystal analysis.
1999, 10(1): 27-28
Abstract:
Six antigenic peptides of 26 kDa glutathione S-transferase of Schistosoma japonicum (Sj26) have been predicted according to their hydrophilicity. flexibility, accessibility, charge distribution and β -turn in the secondary structure by the determination of its primary structure and synthesized by solid phase method. All of them showed antigenicity with anti-schistosoma japonicum immunoglobulin polyclonal antibody, anti-Sj-IgG PcAb by Dot-ELISA. Three of them showed good antigenicity. They would serve as candidates of synthetic anti-schistosomal vaccine.
Six antigenic peptides of 26 kDa glutathione S-transferase of Schistosoma japonicum (Sj26) have been predicted according to their hydrophilicity. flexibility, accessibility, charge distribution and β -turn in the secondary structure by the determination of its primary structure and synthesized by solid phase method. All of them showed antigenicity with anti-schistosoma japonicum immunoglobulin polyclonal antibody, anti-Sj-IgG PcAb by Dot-ELISA. Three of them showed good antigenicity. They would serve as candidates of synthetic anti-schistosomal vaccine.
1999, 10(1): 29-30
Abstract:
A new bisabolane sesquiterpene, 5β-acetoxy-4β, 8- diangeloyloxy-2β, 3β,:10, 11-diepoxy-bisabola-7 (14)-ene, was isolated from the roots of Ligularia songarica and its structure was elucidated on the basis of spectroscopic methods, especially 2D-NMR techniques.
A new bisabolane sesquiterpene, 5β-acetoxy-4β, 8- diangeloyloxy-2β, 3β,:10, 11-diepoxy-bisabola-7 (14)-ene, was isolated from the roots of Ligularia songarica and its structure was elucidated on the basis of spectroscopic methods, especially 2D-NMR techniques.
1999, 10(1): 31-32
Abstract:
Two new diterpenoids, maoecrystal U and epi-maoecrystal P were isolated from the leaves of Isodon eriocalyx. Their structures were determined as 6β-acetoxy-15β-hydroxy-3α, 20epoxy-enf-kaur-16-ene-1, 7-dione 1 and 16 (s)-methoxymethyl-6β, 7β-dihydroxy-7α, 20-epoxy-ent-kaur-2. 3-ethenylene-l. 15-dione 2 respectively, by spectroscopic methods.
Two new diterpenoids, maoecrystal U and epi-maoecrystal P were isolated from the leaves of Isodon eriocalyx. Their structures were determined as 6β-acetoxy-15β-hydroxy-3α, 20epoxy-enf-kaur-16-ene-1, 7-dione 1 and 16 (s)-methoxymethyl-6β, 7β-dihydroxy-7α, 20-epoxy-ent-kaur-2. 3-ethenylene-l. 15-dione 2 respectively, by spectroscopic methods.
1999, 10(1): 33-36
Abstract:
A new triterpenoid saponin, named silenoside, with sugar chains esterified by two different acyl groups was isolated from Silene szechuensis. Its structure was elucidated by chemical and spectral methods.
A new triterpenoid saponin, named silenoside, with sugar chains esterified by two different acyl groups was isolated from Silene szechuensis. Its structure was elucidated by chemical and spectral methods.
1999, 10(1): 37-38
Abstract:
A new 7-9'-monoepoxy tetrahydrofuran type lignan glucoside with the cis-relationship of H-7 and H-8, named tibeticoside A 1, was isolated from the medicinal whole plants of Lancea tibetica. Its structure was elucidated by spectroscopic methods and chemical transformation.
A new 7-9'-monoepoxy tetrahydrofuran type lignan glucoside with the cis-relationship of H-7 and H-8, named tibeticoside A 1, was isolated from the medicinal whole plants of Lancea tibetica. Its structure was elucidated by spectroscopic methods and chemical transformation.
1999, 10(1): 39-42
Abstract:
Sulfobutylether-β-cyclodextrin (SBE-β-CD) was used as a chiral selector for separating ten chiral drugs with resolution ≥ 1.2 by capillary zone electrophoresis (CZE), The background electrolyte solution comprised of 120 mmol/L Britton-Robinson buffer (BRB) containing 1~10 mmol/L SBE-β-CD with the pH value adjusted from 5.0~6.8. Five of the drugs were better resolved than those previously reported with neutral CDs.
Sulfobutylether-β-cyclodextrin (SBE-β-CD) was used as a chiral selector for separating ten chiral drugs with resolution ≥ 1.2 by capillary zone electrophoresis (CZE), The background electrolyte solution comprised of 120 mmol/L Britton-Robinson buffer (BRB) containing 1~10 mmol/L SBE-β-CD with the pH value adjusted from 5.0~6.8. Five of the drugs were better resolved than those previously reported with neutral CDs.
1999, 10(1): 43-44
Abstract:
Taxayuntin I, a new 11 (15->l)abeotaxane, was isolated from the leaves and stems of Taxus yunnanensis. Its structure was elucidated on the basis of spectroscopic data.
Taxayuntin I, a new 11 (15->l)abeotaxane, was isolated from the leaves and stems of Taxus yunnanensis. Its structure was elucidated on the basis of spectroscopic data.
1999, 10(1): 45-46
Abstract:
An excellent separation of xylene isomers is reported using 2, 6-0-di-pentyl-3-0-acetyl- β -CD as capillary stationary phase. The optimum conditions for the separation are also discussed.
An excellent separation of xylene isomers is reported using 2, 6-0-di-pentyl-3-0-acetyl- β -CD as capillary stationary phase. The optimum conditions for the separation are also discussed.
1999, 10(1): 47-50
Abstract:
The reduction of nitrite at Au or carbon electrode in H2SO4 was found to follow a chemical-electrochemical (CE) mechanism with a very thin (4x10-8 cm) preceding reaction zone. It was proposed and experimentally verified that for such kind of electrode processes the total reaction rate could be effectively enhanced by using electrodes with increased true surface area, such as porous electrodes. As a combination of porous electrode and microelectrode, the powder microelectrode shows excellent performance for nitrite detection.
The reduction of nitrite at Au or carbon electrode in H2SO4 was found to follow a chemical-electrochemical (CE) mechanism with a very thin (4x10-8 cm) preceding reaction zone. It was proposed and experimentally verified that for such kind of electrode processes the total reaction rate could be effectively enhanced by using electrodes with increased true surface area, such as porous electrodes. As a combination of porous electrode and microelectrode, the powder microelectrode shows excellent performance for nitrite detection.
1999, 10(1): 51-54
Abstract:
Based on the inhibitory effect of metal ions on the decolourization reaction of a dye taking place in a mixed micellar medium, a differential rate method was developed for the detection of metal ions. The present kinetic spectrophotometric system has several advantages due to introduction of the mixed micelles.
Based on the inhibitory effect of metal ions on the decolourization reaction of a dye taking place in a mixed micellar medium, a differential rate method was developed for the detection of metal ions. The present kinetic spectrophotometric system has several advantages due to introduction of the mixed micelles.
1999, 10(1): 55-58
Abstract:
Guillain-Barre syndrome (GBS) is considered to be an autoimmune disorder of peripheral nervous system. In this paper, capillary SDS gel electrophoresis was performed on neutral coated fused-silica capillary to determine the molecular weight of purified IgG samples from GBS patient.
Guillain-Barre syndrome (GBS) is considered to be an autoimmune disorder of peripheral nervous system. In this paper, capillary SDS gel electrophoresis was performed on neutral coated fused-silica capillary to determine the molecular weight of purified IgG samples from GBS patient.
1999, 10(1): 59-62
Abstract:
The fluorescence spectra of the poly (N-vinylcarbazole) in solution obtained with chirally organic salts or acid as catalyst or initiator[(-)Sp:(-)-Sparteine, (+)CSA:D- (+)-Camphor-10-sulfonic acid)], respectively, have been investigated. It is found that the two emission peaks at the longer wavelength (λmax,ca, 415nm) and the shorter wavelength (λmax,ca,370nm) are assigned to the sandwich excimer and second excimer (partial overlap) fluorescence, respectively. The sandwich excimer and partially overlapped excimer are attributed to a fully overlapped structure of neighbouring carbazole chromophores in a totally elipsed conformation of the isotactic sequence, and partially overlapped structure of the syndiotactic sequence. The estimated values of I4l5/I370 and isotactic sequence content by using the fluorescence spectra are in the order:(-)Sp+ (+)CSA > (+)CSA > (-)Sp+C104- (no peak at 415nm for AIBN).
The fluorescence spectra of the poly (N-vinylcarbazole) in solution obtained with chirally organic salts or acid as catalyst or initiator[(-)Sp:(-)-Sparteine, (+)CSA:D- (+)-Camphor-10-sulfonic acid)], respectively, have been investigated. It is found that the two emission peaks at the longer wavelength (λmax,ca, 415nm) and the shorter wavelength (λmax,ca,370nm) are assigned to the sandwich excimer and second excimer (partial overlap) fluorescence, respectively. The sandwich excimer and partially overlapped excimer are attributed to a fully overlapped structure of neighbouring carbazole chromophores in a totally elipsed conformation of the isotactic sequence, and partially overlapped structure of the syndiotactic sequence. The estimated values of I4l5/I370 and isotactic sequence content by using the fluorescence spectra are in the order:(-)Sp+ (+)CSA > (+)CSA > (-)Sp+C104- (no peak at 415nm for AIBN).
1999, 10(1): 63-66
Abstract:
In this letter, vve report that oxidation of 4-aminothiophenol self-assembled monolayer on Au electrode produces a couple of redox current peaks with close peak potentials in 0.5 mol/L HCIO4 aqueous solution, and the peaks are ascribed to an electroactive monolayer. Electrochemical properties of the monolayer polymer were investigated with use of electrochemical quartz crystal microbalance and cyclic voltammetry.
In this letter, vve report that oxidation of 4-aminothiophenol self-assembled monolayer on Au electrode produces a couple of redox current peaks with close peak potentials in 0.5 mol/L HCIO4 aqueous solution, and the peaks are ascribed to an electroactive monolayer. Electrochemical properties of the monolayer polymer were investigated with use of electrochemical quartz crystal microbalance and cyclic voltammetry.
1999, 10(1): 67-68
Abstract:
Poly (ethyl acrylate-co-lithium methacrylate) (PEM) latex film was synthesized by emulsion-free polymerization. The electrochemical window of plasticized PEM latex film is exceeding 5.0 V. LiCo02/Li battery with PEM latex film as electrolyte exhibits excellent reversibility and when the discharge current density is 0.3 mA/cm2, the specific discharge capacity achieves 4.4 mAh/cm2.
Poly (ethyl acrylate-co-lithium methacrylate) (PEM) latex film was synthesized by emulsion-free polymerization. The electrochemical window of plasticized PEM latex film is exceeding 5.0 V. LiCo02/Li battery with PEM latex film as electrolyte exhibits excellent reversibility and when the discharge current density is 0.3 mA/cm2, the specific discharge capacity achieves 4.4 mAh/cm2.
1999, 10(1): 69-72
Abstract:
Acrylamide was used as functional monomer to make high chiral selective molecule imprinting polymers against Nα-protected amino acid in polar solvent. The factor, which influence the efficiency of the polymer and the mechanism of chiral recognition were investigated.
Acrylamide was used as functional monomer to make high chiral selective molecule imprinting polymers against Nα-protected amino acid in polar solvent. The factor, which influence the efficiency of the polymer and the mechanism of chiral recognition were investigated.
1999, 10(1): 73-76
Abstract:
Electrochemical quartz crystal impedance system (EQCIS) which allows in situ dynamic quartz crystal impedance measurement in an electrochemical experiment was developed by combining an HP 4395A Network/Spectrum/Impedance analyzer with an EG&G M283 potentiostat. Equivalent circuit parameters of crystal resonance change significantly during electrodeposition and dissolution of copper in 0.1 mol/L H2S04 aqueous solution in a cyclic potential sweep experiment, which is explained with an overall picture of mass loading, solution density and viscosity, etc.
Electrochemical quartz crystal impedance system (EQCIS) which allows in situ dynamic quartz crystal impedance measurement in an electrochemical experiment was developed by combining an HP 4395A Network/Spectrum/Impedance analyzer with an EG&G M283 potentiostat. Equivalent circuit parameters of crystal resonance change significantly during electrodeposition and dissolution of copper in 0.1 mol/L H2S04 aqueous solution in a cyclic potential sweep experiment, which is explained with an overall picture of mass loading, solution density and viscosity, etc.
1999, 10(1): 77-78
Abstract:
The reactions of 5- (p-hydroxyphenyl)-lO, 15. 20-tris (p-methoxyphenyl) porphyrin (H2Por) 1 respectively with triruthenium dodecacarbonyl[Ru3 (CO)12] and triosmium dodecacarbonyl[Os3 (CO)12] under N2 gave complexes 2 and 3. Treatment of 2 (and 3) with Memfield' peptide resin gave 4 (and 5) respectively.
The reactions of 5- (p-hydroxyphenyl)-lO, 15. 20-tris (p-methoxyphenyl) porphyrin (H2Por) 1 respectively with triruthenium dodecacarbonyl[Ru3 (CO)12] and triosmium dodecacarbonyl[Os3 (CO)12] under N2 gave complexes 2 and 3. Treatment of 2 (and 3) with Memfield' peptide resin gave 4 (and 5) respectively.
1999, 10(1): 79-82
Abstract:
The dioxygen affinities and catalytic epoxidation performance of transition-metal hydroxamates were investigated for the first time. The effects of substituents on these properties were also discussed in the paper.
The dioxygen affinities and catalytic epoxidation performance of transition-metal hydroxamates were investigated for the first time. The effects of substituents on these properties were also discussed in the paper.
1999, 10(1): 83-86
Abstract:
The catalytic decomposition of NO over Ag-ZSM-5 catalyst prepared by ion-exchange was investigated. The exchanged silver in the zeolite was reduced and it collected in the course of the reaction to form silver particles of about 20 nm. The catalytic reaction induced a pronounced restructuring of the Ag particles through preferential formation of the (111) facets. These facets were shown to bind a tightly bound oxygen species (0Y). The OY species occupies the active sites for NO adsorption resulting in catalyst deactivation. It could be removed by appropriate reducing agents, such as CO, to recover the active sites at elevated temperatures.
The catalytic decomposition of NO over Ag-ZSM-5 catalyst prepared by ion-exchange was investigated. The exchanged silver in the zeolite was reduced and it collected in the course of the reaction to form silver particles of about 20 nm. The catalytic reaction induced a pronounced restructuring of the Ag particles through preferential formation of the (111) facets. These facets were shown to bind a tightly bound oxygen species (0Y). The OY species occupies the active sites for NO adsorption resulting in catalyst deactivation. It could be removed by appropriate reducing agents, such as CO, to recover the active sites at elevated temperatures.
1999, 10(1): 87-90
Abstract:
Lead (Ⅱ)-binding properties of rabbit liver thionein 2 (apo-MT2) have been studied. Two kinds of complexes, Pb7-MT and Pb7-MT', are observed upon the binding of Pb2+ to apo-MT at different pH. From their characteristic peaks in UV and CD spectra, it is deduced that Pb2+ in Pb7-MT is coordinated by four sulfhydryl groups in Td microsymmetry, while multiple coordination types including two-coordination maybe present in Pb7-MT'.
Lead (Ⅱ)-binding properties of rabbit liver thionein 2 (apo-MT2) have been studied. Two kinds of complexes, Pb7-MT and Pb7-MT', are observed upon the binding of Pb2+ to apo-MT at different pH. From their characteristic peaks in UV and CD spectra, it is deduced that Pb2+ in Pb7-MT is coordinated by four sulfhydryl groups in Td microsymmetry, while multiple coordination types including two-coordination maybe present in Pb7-MT'.
1999, 10(1): 91-94
Abstract:
The relationship between bond valence and bond covalency in RMn205 (R=La, Pr, Nd, Sm, Eu) has been investigated by a semiempirical method. This method is the generalization of the dielectric description theory of Phillips, Van Vechten, Levine and Tanaka scheme. The results indicate that larger valences usually result in higher bond covalencies, in good agreement with the point that the excess charge in the bonding region is the origin of formation of bond covalency. Other factors, such as oxidation state of elements, only make a small contribution to bond covalency.
The relationship between bond valence and bond covalency in RMn205 (R=La, Pr, Nd, Sm, Eu) has been investigated by a semiempirical method. This method is the generalization of the dielectric description theory of Phillips, Van Vechten, Levine and Tanaka scheme. The results indicate that larger valences usually result in higher bond covalencies, in good agreement with the point that the excess charge in the bonding region is the origin of formation of bond covalency. Other factors, such as oxidation state of elements, only make a small contribution to bond covalency.
