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1997 Volume 8 Issue 9
1997, 8(9): 747-748
Abstract:
PEG (polyethylene glycol.average molecular weight 300) is used as absorbent of NO2.The absorption efficiency is found to reach up to 97%.The absorbing product,PEG·NO2,can be used to cleave benzyl ethers mildly and selectively to benzaldehyde and corresponding fatty alcohols showing that PEG is a valuable oxidizing agent of benzyl ethers.As a carrier of NO2,PEG can be recovered and utilized repeatedly after the oxidation.
PEG (polyethylene glycol.average molecular weight 300) is used as absorbent of NO2.The absorption efficiency is found to reach up to 97%.The absorbing product,PEG·NO2,can be used to cleave benzyl ethers mildly and selectively to benzaldehyde and corresponding fatty alcohols showing that PEG is a valuable oxidizing agent of benzyl ethers.As a carrier of NO2,PEG can be recovered and utilized repeatedly after the oxidation.
1997, 8(9): 749-750
Abstract:
DEPBT,a novel coupling reagent containing phosphorus,was used in synthesis of pentapeptide Boc-Ile-Asn-Met-Trp (For)-Gly OMe by solution method.
DEPBT,a novel coupling reagent containing phosphorus,was used in synthesis of pentapeptide Boc-Ile-Asn-Met-Trp (For)-Gly OMe by solution method.
1997, 8(9): 751-754
Abstract:
The cyclization reactions of Lawesson's reagent(LR) with the substrates containing two functional groups such as hydroxy groups,amino groups,has been applied to prepare the O-P-O,N-P-N type 5-membered and 6-membered phosphorus heterocycles.The heterocyclizational possibility of LR with bifunctional compounds was also discussed.
The cyclization reactions of Lawesson's reagent(LR) with the substrates containing two functional groups such as hydroxy groups,amino groups,has been applied to prepare the O-P-O,N-P-N type 5-membered and 6-membered phosphorus heterocycles.The heterocyclizational possibility of LR with bifunctional compounds was also discussed.
1997, 8(9): 755-758
Abstract:
The condensation of aromatic aldehydes with isopropylidene malonate or 5,5-dimethyl-1,3-cyclohexanedione is carried out by DMF as solvent without catalyst.
The condensation of aromatic aldehydes with isopropylidene malonate or 5,5-dimethyl-1,3-cyclohexanedione is carried out by DMF as solvent without catalyst.
1997, 8(9): 759-762
Abstract:
Allyl and cinnamyl and propargyl bromide reacted under mild conditions with triarylbismuth under catalysis by Pd(0) to give 3-arylpropenes,1,3-diarylpropenes and arylpropadienes in modest to excellent yields.
Allyl and cinnamyl and propargyl bromide reacted under mild conditions with triarylbismuth under catalysis by Pd(0) to give 3-arylpropenes,1,3-diarylpropenes and arylpropadienes in modest to excellent yields.
1997, 8(9): 763-764
Abstract:
A high turnover number was achieved in the photocatalytic carbonylation of C-H bonds of cyclohexane catalyzed by Co (acac)2 under ambient conditions (1 atm,25℃)to give mainly cyclohexanecarboxaldehyde.
A high turnover number was achieved in the photocatalytic carbonylation of C-H bonds of cyclohexane catalyzed by Co (acac)2 under ambient conditions (1 atm,25℃)to give mainly cyclohexanecarboxaldehyde.
1997, 8(9): 765-768
Abstract:
The investigation of the scope and limitation of retro-Micheal reaction of 1,5-dicarbonyl compounds showed that the reaction worked well for 1,5-diketones and 1,5-ketoaldehydes but gave poor yield for 1,5-ketoesters and 1,5-ketoacids.
The investigation of the scope and limitation of retro-Micheal reaction of 1,5-dicarbonyl compounds showed that the reaction worked well for 1,5-diketones and 1,5-ketoaldehydes but gave poor yield for 1,5-ketoesters and 1,5-ketoacids.
1997, 8(9): 769-772
Abstract:
3-(3,5-Dimethoxybenzyl)-5-hexenoic acid (13) could be cycloacylated by a variant consistion of treating its mixed formate anhydride with tin chloride to give a moderate yield of 3-allyl-6,8-dimethoxy-1-tetralone (24).Both allyl chains of unsaturated acid 13 and substituted tetralone 24 could be hydroxylated with concentrated sulfuric acid.These results make possible a study of synthesis of some natural perylenequinones and their stereochemistry.
3-(3,5-Dimethoxybenzyl)-5-hexenoic acid (13) could be cycloacylated by a variant consistion of treating its mixed formate anhydride with tin chloride to give a moderate yield of 3-allyl-6,8-dimethoxy-1-tetralone (24).Both allyl chains of unsaturated acid 13 and substituted tetralone 24 could be hydroxylated with concentrated sulfuric acid.These results make possible a study of synthesis of some natural perylenequinones and their stereochemistry.
1997, 8(9): 773-776
Abstract:
A new approach to the construction of pyrrolizidine and indolizidine skeleton was described.By employing this cvclization method,the synthesis of (1S.7aS)-1-hydroxypyrrolizidine (1a) and (1S.8aS)-1-hydroxyindolizidine (1b) was achieved by treatment of the trimesylate 6a or 6b with aqueous ammonia in the presence of K2CO3 (or Cs2CO3) in one-pot fashion.
A new approach to the construction of pyrrolizidine and indolizidine skeleton was described.By employing this cvclization method,the synthesis of (1S.7aS)-1-hydroxypyrrolizidine (1a) and (1S.8aS)-1-hydroxyindolizidine (1b) was achieved by treatment of the trimesylate 6a or 6b with aqueous ammonia in the presence of K2CO3 (or Cs2CO3) in one-pot fashion.
1997, 8(9): 777-778
Abstract:
The synthesis of a novel type of calixcrown 5,11,17,23-p-tert-butyl-25,27 dihy-droxy-26,28-(3',7'-diselena-5',5'-dimethylnonylene) dioxy-calix[4] arene is described.
The synthesis of a novel type of calixcrown 5,11,17,23-p-tert-butyl-25,27 dihy-droxy-26,28-(3',7'-diselena-5',5'-dimethylnonylene) dioxy-calix[4] arene is described.
1997, 8(9): 779-780
Abstract:
The substrate hippuryl phenylalanine of carboxypeptidase A was selected as model to design new hapten molecule.N-Benzoyl tauryl phenylalanine (Ⅰ) was synthesized and its structure was characterized by X-ray crystallography method.
The substrate hippuryl phenylalanine of carboxypeptidase A was selected as model to design new hapten molecule.N-Benzoyl tauryl phenylalanine (Ⅰ) was synthesized and its structure was characterized by X-ray crystallography method.
1997, 8(9): 781-784
Abstract:
The product,obtained by the photoaddition of terpinolene to methyl 2.4-dioxopentanoate.was subjected to cyclization to generate a spirocyclic compound having spiro[5.5] undecan structure,which was further transformed into α-Chamigrene-3-one by subsequent reactions.
The product,obtained by the photoaddition of terpinolene to methyl 2.4-dioxopentanoate.was subjected to cyclization to generate a spirocyclic compound having spiro[5.5] undecan structure,which was further transformed into α-Chamigrene-3-one by subsequent reactions.
1997, 8(9): 785-788
Abstract:
Diosgenyl α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (1) and Diosgenyl α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranoside (2) were shown to be fascinating "facial amphiphiles" by conformational analysis based on NOE-MD method.
Diosgenyl α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside (1) and Diosgenyl α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranoside (2) were shown to be fascinating "facial amphiphiles" by conformational analysis based on NOE-MD method.
1997, 8(9): 789-790
Abstract:
The absolute stereochemistries of Annonaceous acetogenins.tonkinin A and B,have been established by the use of the convenient conversion to their formaldehyde acetal derivatives and the subsequent application of the Mosher ester methodology.
The absolute stereochemistries of Annonaceous acetogenins.tonkinin A and B,have been established by the use of the convenient conversion to their formaldehyde acetal derivatives and the subsequent application of the Mosher ester methodology.
1997, 8(9): 791-792
Abstract:
The phytochemical investigation of Delphinium tongolense Franck.yielded two new diterpenoid alkaloids tongolenine C and tongolenine D.Their structures were elucidated by spectroscopical methods.
The phytochemical investigation of Delphinium tongolense Franck.yielded two new diterpenoid alkaloids tongolenine C and tongolenine D.Their structures were elucidated by spectroscopical methods.
1997, 8(9): 793-796
Abstract:
Coated capillary columns were prepared by sol-gel technology and used in the separation of basic proteins with capillary zone electrophoresis.The results indicated that a significant decrease in protein adsorption was obtained and EOF was also diminished to zero in the pH range of 3-10.
Coated capillary columns were prepared by sol-gel technology and used in the separation of basic proteins with capillary zone electrophoresis.The results indicated that a significant decrease in protein adsorption was obtained and EOF was also diminished to zero in the pH range of 3-10.
1997, 8(9): 797-880
Abstract:
Cholesterol could be adsorbed on the surface of hanging mercury drop electrode,and gave a sensitive 2.5 order oxidative peak by anodic stripping procedure.The peak potential is-0.01v (Vs SEC).The peak current is linearly proportional to the cholesterol concentration in the range of 1.0×10-5~1.0×10-7mol/L.The dection limit is 5.0×10-8 mol/L.In this paper,The electrode response mechanism of cholesterol has been studied,and the optimum experimental conditons have been found.This new method for determination of cholesterol has been applied to actual samples.
Cholesterol could be adsorbed on the surface of hanging mercury drop electrode,and gave a sensitive 2.5 order oxidative peak by anodic stripping procedure.The peak potential is-0.01v (Vs SEC).The peak current is linearly proportional to the cholesterol concentration in the range of 1.0×10-5~1.0×10-7mol/L.The dection limit is 5.0×10-8 mol/L.In this paper,The electrode response mechanism of cholesterol has been studied,and the optimum experimental conditons have been found.This new method for determination of cholesterol has been applied to actual samples.
1997, 8(9): 801-802
Abstract:
The electrochemical reduction of alkylaquabis(dimethylglyoximato) Cobalt (Ⅲ) in the absence and presence of β-Cyclodextrin (β-CD) was investigated by means of cyclic voltammetry.It was found that β-CD facilitates the cleavage of Co-C bond during the reduction process.
The electrochemical reduction of alkylaquabis(dimethylglyoximato) Cobalt (Ⅲ) in the absence and presence of β-Cyclodextrin (β-CD) was investigated by means of cyclic voltammetry.It was found that β-CD facilitates the cleavage of Co-C bond during the reduction process.
1997, 8(9): 803-804
Abstract:
The interaction of β-cyclodextrin (β-CD),hydroxypropyl-β-CD and γ-CD with the drug rutin has been investigated by usingfluorimetry.The stoichiometry of the complexes and their formation constants have been estimated.The thermodynamic parameters for the formation of complexes were obtained.The complexing ability of HP-β-CD is remarkably stronger than β-CD and γ-CD.
The interaction of β-cyclodextrin (β-CD),hydroxypropyl-β-CD and γ-CD with the drug rutin has been investigated by usingfluorimetry.The stoichiometry of the complexes and their formation constants have been estimated.The thermodynamic parameters for the formation of complexes were obtained.The complexing ability of HP-β-CD is remarkably stronger than β-CD and γ-CD.
1997, 8(9): 805-806
Abstract:
The clusters generated by direct laser vaporization of KH2PO4 and Cu3(PO4)2 samples are studied by a TOF mass spectrometer.It is found that mainly the[K(KPO3)n] cluster series is generated from KH2PO4 sample and it demonstrates obvious magic numbers,which are n=3,6,9,12,15.Direct laser vaporization of Cu3(PO4)2 sample produced[Cu(CuPO3)n] cluster series as well as other series with the same building block of (CuPO3).
The clusters generated by direct laser vaporization of KH2PO4 and Cu3(PO4)2 samples are studied by a TOF mass spectrometer.It is found that mainly the[K(KPO3)n] cluster series is generated from KH2PO4 sample and it demonstrates obvious magic numbers,which are n=3,6,9,12,15.Direct laser vaporization of Cu3(PO4)2 sample produced[Cu(CuPO3)n] cluster series as well as other series with the same building block of (CuPO3).
1997, 8(9): 807-810
Abstract:
A new PVK-based photorefractive polymer composite sensitized by C60 and doped with a higher content of EO chromophore was prepared.The high optical quality thin-film was formed between two ITO-covered glass electrodes.Two-beam-coupling (2BC) experiment was performed by using a He-Ne laser (at wavelength 632.8nm),and an obvious photorefractive performance was observed.The dependence of two-beam-coupling gain coefficient on the applied poling dc electric field was measured.
A new PVK-based photorefractive polymer composite sensitized by C60 and doped with a higher content of EO chromophore was prepared.The high optical quality thin-film was formed between two ITO-covered glass electrodes.Two-beam-coupling (2BC) experiment was performed by using a He-Ne laser (at wavelength 632.8nm),and an obvious photorefractive performance was observed.The dependence of two-beam-coupling gain coefficient on the applied poling dc electric field was measured.
1997, 8(9): 811-814
Abstract:
A new copper phthalocyanine-fullerene dyad (CuPc-C60) was synthesized by Diels-Alder adduct of corresponding CuPc and C60.The chemical structure of this compound was characterized by elemental analysis,MS,IR,UV-VIS and NMR.
A new copper phthalocyanine-fullerene dyad (CuPc-C60) was synthesized by Diels-Alder adduct of corresponding CuPc and C60.The chemical structure of this compound was characterized by elemental analysis,MS,IR,UV-VIS and NMR.
1997, 8(9): 815-818
Abstract:
The synthesis of phthalocyanines bearing one crown ether macrocycle and three alkoxyl chains is described.They form stable monolayers and can be employed for the preparation of multilayer films by the Langmuir-Blogett technique.The orientations of the molecules in the film were affected by alkali metal ions in the subphase.It is suggested that a kind of "sandwich" dimer was formed in the film induced by potassium ions.
The synthesis of phthalocyanines bearing one crown ether macrocycle and three alkoxyl chains is described.They form stable monolayers and can be employed for the preparation of multilayer films by the Langmuir-Blogett technique.The orientations of the molecules in the film were affected by alkali metal ions in the subphase.It is suggested that a kind of "sandwich" dimer was formed in the film induced by potassium ions.
1997, 8(9): 819-820
Abstract:
A series of 3-trichlorostannylpropionate complexes with dibutylsulfoxide and pyridine oxide were synthesized by transesterification reaction and characterized by means of elemental analysis,IR,NMR (1H,13C) and X-ray single crystal diffraction.
A series of 3-trichlorostannylpropionate complexes with dibutylsulfoxide and pyridine oxide were synthesized by transesterification reaction and characterized by means of elemental analysis,IR,NMR (1H,13C) and X-ray single crystal diffraction.
1997, 8(9): 821-824
Abstract:
The lytropic liquid crystals in dodecanic acid diethanolamine (DAD)/n-butanol (C4OH)/octane (n-C8H18)/deuteron (D2O) system were studied to determine the phase regions and were investigated by 2H-NMR spectroscopy,optical polarizing microscope and small-angle X-ray diffraction (SAXD) methods.The results indicate that the lamellar,hexagonal and cubic liquid crystals all exist in the above system.Keeping the weight ratio of DAD and C4OH constant,the microphase structure,2H quadruple splitting and the interlayer spacing are all changed with the addition of deuteron.
The lytropic liquid crystals in dodecanic acid diethanolamine (DAD)/n-butanol (C4OH)/octane (n-C8H18)/deuteron (D2O) system were studied to determine the phase regions and were investigated by 2H-NMR spectroscopy,optical polarizing microscope and small-angle X-ray diffraction (SAXD) methods.The results indicate that the lamellar,hexagonal and cubic liquid crystals all exist in the above system.Keeping the weight ratio of DAD and C4OH constant,the microphase structure,2H quadruple splitting and the interlayer spacing are all changed with the addition of deuteron.
1997, 8(9): 825-828
Abstract:
The diffusion coefficients(Dapp) and the heterogeneous electron-transfer rate constants(ks) for ferrocene and its seven derivatives in MPEG/LiClO4 electrolyte were determined by using steady-state voltammetry.The two parameters increase with increasing temperature,indicating Arrhenius behavior.The effects of the nature of electroactive solute molecules on Dapp,ks,and the half-wave potentials(E1/2) are discussed.
The diffusion coefficients(Dapp) and the heterogeneous electron-transfer rate constants(ks) for ferrocene and its seven derivatives in MPEG/LiClO4 electrolyte were determined by using steady-state voltammetry.The two parameters increase with increasing temperature,indicating Arrhenius behavior.The effects of the nature of electroactive solute molecules on Dapp,ks,and the half-wave potentials(E1/2) are discussed.
1997, 8(9): 829-830
Abstract:
The [Zr6(μ2-Cl)12Cl6H4]3- ion with C4v symmetry in the title compounds has been calculated by DV-Xα program.The calculated results show that there is almost no available covalence bonding between zirconium atoms and significant Zr 4d AO compositions in the MOs.but there are much stronger Zr-Cl(bridging) bonding.All analysis results suggest that these compounds would be the cluster with Zr6Cl12cage linked by Zr-Cl bridging bonding plus six Cl terminal ligands rather than the hexazirconium cluster in view of the chemical bonding.
The [Zr6(μ2-Cl)12Cl6H4]3- ion with C4v symmetry in the title compounds has been calculated by DV-Xα program.The calculated results show that there is almost no available covalence bonding between zirconium atoms and significant Zr 4d AO compositions in the MOs.but there are much stronger Zr-Cl(bridging) bonding.All analysis results suggest that these compounds would be the cluster with Zr6Cl12cage linked by Zr-Cl bridging bonding plus six Cl terminal ligands rather than the hexazirconium cluster in view of the chemical bonding.
1997, 8(9): 831-832
Abstract:
Nanocrystalline CdSe thin film prepared by chemical solution deposition was imaged in air with a scanning tunneling microscope (STM).Scanning tunneling current spectroscopy(STS) was taken at a fixed tip-sample separation.Tunneling current (i)-voltage(v) curve and differential conductance spectrum show an n-type schottky rectifying behaviour and yield a direct measure of band gap energy.An increase of bandgap energy (1.8-2.1eV) was measured indicating energy quantization of this particular thin film.
Nanocrystalline CdSe thin film prepared by chemical solution deposition was imaged in air with a scanning tunneling microscope (STM).Scanning tunneling current spectroscopy(STS) was taken at a fixed tip-sample separation.Tunneling current (i)-voltage(v) curve and differential conductance spectrum show an n-type schottky rectifying behaviour and yield a direct measure of band gap energy.An increase of bandgap energy (1.8-2.1eV) was measured indicating energy quantization of this particular thin film.
1997, 8(9): 833-836
Abstract:
Zeolite ZSM-35 was synthesized using hexamethyleneimine as an organic template and its crystallographic structure was studied by X-ray diffraction and IR spectroscopy.Its adsorption property was also evaluated.
Zeolite ZSM-35 was synthesized using hexamethyleneimine as an organic template and its crystallographic structure was studied by X-ray diffraction and IR spectroscopy.Its adsorption property was also evaluated.
1997, 8(9): 837-840
Abstract:
The atomic weight of germanium was determined as Ar (Ge)=72.6284 (22).Application of substitute calibration using the true isotopic ratio of Ga69/71 results in Ar(Ge)=72.6389 (29),both on 2σ basis.
The atomic weight of germanium was determined as Ar (Ge)=72.6284 (22).Application of substitute calibration using the true isotopic ratio of Ga69/71 results in Ar(Ge)=72.6389 (29),both on 2σ basis.
