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1991 Volume 2 Issue 6
1991, 2(6): 423-424
Abstract:
(E,E)-2,8-dimethyl-5-isoprepenyl-2,8-decadien-1,10-diol (1),a key intermediate for the synthesis of β-elemene (2),was prepared through 5 steps from geraniol.
(E,E)-2,8-dimethyl-5-isoprepenyl-2,8-decadien-1,10-diol (1),a key intermediate for the synthesis of β-elemene (2),was prepared through 5 steps from geraniol.
1991, 2(6): 425-428
Abstract:
The first synthesis of dehydrobaimuxinol 1 in seven steps and isobaimuxinol 2 by further hydrogenation has been achieved in a stereoselective manner from (-)-carvone.The key step is the regiospecific and exclusive mono-substitution at C-4 to give the enone intermediate 8.The absolute configurations of these two natural products[2] have been unambiguously established by the present synthesis.
The first synthesis of dehydrobaimuxinol 1 in seven steps and isobaimuxinol 2 by further hydrogenation has been achieved in a stereoselective manner from (-)-carvone.The key step is the regiospecific and exclusive mono-substitution at C-4 to give the enone intermediate 8.The absolute configurations of these two natural products[2] have been unambiguously established by the present synthesis.
1991, 2(6): 429-432
Abstract:
The photostimulated reactions of aryl halides with phenothiazinyl and benziraidazolyl nitrogen anion,in dimethyl sulfoxide,form the corresponding N-arylated products.These reactions are promised to occur by the SRN1 mechanism of nucleophilic substitution.
The photostimulated reactions of aryl halides with phenothiazinyl and benziraidazolyl nitrogen anion,in dimethyl sulfoxide,form the corresponding N-arylated products.These reactions are promised to occur by the SRN1 mechanism of nucleophilic substitution.
1991, 2(6): 433-436
Abstract:
A series of new N-aryl-N'-(5-aryl-2-furoyl)thioureas were synthesized by means of solid-liquid phase transfer catalysis.The promoting effects of these new compounds on wheat growth were observed.
A series of new N-aryl-N'-(5-aryl-2-furoyl)thioureas were synthesized by means of solid-liquid phase transfer catalysis.The promoting effects of these new compounds on wheat growth were observed.
OXYGENATION OF AROMATIC ALDEHYDES BY THE MANGANESE(111) PORPHYRIN COMPLEX-SODIUM HYPOCHLORITE SYSTEM
1991, 2(6): 437-438
Abstract:
Aromatic aldehydes have been oxidized to their corresponding carboxylic acids in good yields.The reactions were performed in the manganese(111) porphyrin complex-sodium hypochlorite system under mild conditions.
Aromatic aldehydes have been oxidized to their corresponding carboxylic acids in good yields.The reactions were performed in the manganese(111) porphyrin complex-sodium hypochlorite system under mild conditions.
1991, 2(6): 439-440
Abstract:
Reduction of 4-nitroketones with TiCl4-Zn reagent affords △'-pyrrolines(2);a special case is the formation of 8-azabicyclo[3,2,1]octane(4) from 4-nitro-1,7-alkadione(3) by the same method;the stereochemistry has been confirmed by X-ray crystal structure determination of (4a).
Reduction of 4-nitroketones with TiCl4-Zn reagent affords △'-pyrrolines(2);a special case is the formation of 8-azabicyclo[3,2,1]octane(4) from 4-nitro-1,7-alkadione(3) by the same method;the stereochemistry has been confirmed by X-ray crystal structure determination of (4a).
1991, 2(6): 441-442
Abstract:
An extract of the barks of Taxus yunnanensis has afforded eight constituents,taxane diterpenoids and alkaloids,of which one appear to be new.The structure of the new taxane diterpene,named yunnanxane(Ⅰ) was elucidated by spectroscopic means (UV,IR,MS,1H NMR,13C NMR,1H-1H COSY,13C-1H COSY and 13C-1H COLOC) and X-ray diffraction analysis.
An extract of the barks of Taxus yunnanensis has afforded eight constituents,taxane diterpenoids and alkaloids,of which one appear to be new.The structure of the new taxane diterpene,named yunnanxane(Ⅰ) was elucidated by spectroscopic means (UV,IR,MS,1H NMR,13C NMR,1H-1H COSY,13C-1H COSY and 13C-1H COLOC) and X-ray diffraction analysis.
1991, 2(6): 443-446
Abstract:
The influence of n-tetrabutylammonium tetrafluoroborate(R4NBF4) on the conversion and product distribution is studied in 9,10-dicyanoanthracence(DCA) sensitized photooxidation of 3,4-dihydro-2H-pyran (DHP).The source of singlet oxygen in this reaction is discussed and electron transfer mechanism is confirmed by the observation of salt effect.
The influence of n-tetrabutylammonium tetrafluoroborate(R4NBF4) on the conversion and product distribution is studied in 9,10-dicyanoanthracence(DCA) sensitized photooxidation of 3,4-dihydro-2H-pyran (DHP).The source of singlet oxygen in this reaction is discussed and electron transfer mechanism is confirmed by the observation of salt effect.
1991, 2(6): 447-450
Abstract:
Tetraalkylammonium hydroxides were used in coupled oxidation of hemin.The alkyl substitutes on ammonium restricted the accessibility of active oxygen species to methine bridges of hemin and produced various compositions of biliverdin Ⅸ isomers.The content of Ⅸα isomer could reach to more than 60%.
Tetraalkylammonium hydroxides were used in coupled oxidation of hemin.The alkyl substitutes on ammonium restricted the accessibility of active oxygen species to methine bridges of hemin and produced various compositions of biliverdin Ⅸ isomers.The content of Ⅸα isomer could reach to more than 60%.
1991, 2(6): 451-452
Abstract:
Papain was successfully immobilized on flyash-bead,waste from fire-power plant,cross-linked by means of glutaraldehyde.The optimum conditions and the properties of the immobilized papain were studied.The activity of the immobilized papain could be increased about 30% by suitable infrared irradiation.
Papain was successfully immobilized on flyash-bead,waste from fire-power plant,cross-linked by means of glutaraldehyde.The optimum conditions and the properties of the immobilized papain were studied.The activity of the immobilized papain could be increased about 30% by suitable infrared irradiation.
1991, 2(6): 453-456
Abstract:
Retention time of triglyceride by non-aqueous reversed phase HPLC is related to its adjusted total carbon number——theoretical carbon number (TCN).TCN values of fatty acids composing triglycerides are computed by variance analysis through actually determined HPLC retention times of various triglycerides.Predicting triglyceride HPLC retention times is re-alized.
Retention time of triglyceride by non-aqueous reversed phase HPLC is related to its adjusted total carbon number——theoretical carbon number (TCN).TCN values of fatty acids composing triglycerides are computed by variance analysis through actually determined HPLC retention times of various triglycerides.Predicting triglyceride HPLC retention times is re-alized.
1991, 2(6): 457-458
Abstract:
Essential oil was obtained by steam distillation of Michelia leaves.It was analysed and 27 compounds were identified.The main component is linalool.
Essential oil was obtained by steam distillation of Michelia leaves.It was analysed and 27 compounds were identified.The main component is linalool.
1991, 2(6): 459-460
Abstract:
The product with lower melting point of Dieckmann's reaction with 2,2,6,6-tetra(β-ethyl-carboxyethyl) cyclohexanone was verified to be the raceme consisted of (R,R) and (S,S)2,10-di(β-carboxyethyl)-3,11-dihydroxydispiro [5.1.5.3] hexadecan-2,10-dien-7-one (Fig.1 shows the molecular structure )with X-ray diffraction method.
The product with lower melting point of Dieckmann's reaction with 2,2,6,6-tetra(β-ethyl-carboxyethyl) cyclohexanone was verified to be the raceme consisted of (R,R) and (S,S)2,10-di(β-carboxyethyl)-3,11-dihydroxydispiro [5.1.5.3] hexadecan-2,10-dien-7-one (Fig.1 shows the molecular structure )with X-ray diffraction method.
1991, 2(6): 461-462
Abstract:
In this paper Lanthanide-induced shifts have been measured for 13C and 1H nuclei of glycyl-glycine,glycyl-DL-valine and glycyl-L-leucine in the presence of lanthanide cations (La3+,Ho3+ and Yb3+) in aqueous solution.The simulation to conformations of lanthanide dipeptide complexes shows that the ligands are coordinated to lanthanide ions through oxygen donors of carboxyl groups.In the complexes dipeptides are in extended state.
In this paper Lanthanide-induced shifts have been measured for 13C and 1H nuclei of glycyl-glycine,glycyl-DL-valine and glycyl-L-leucine in the presence of lanthanide cations (La3+,Ho3+ and Yb3+) in aqueous solution.The simulation to conformations of lanthanide dipeptide complexes shows that the ligands are coordinated to lanthanide ions through oxygen donors of carboxyl groups.In the complexes dipeptides are in extended state.
1991, 2(6): 463-464
Abstract:
Copper N-(meta-methoxy)-phenyl Iminodiacetate dihydrate,{Cu[CH3OC6H4N(CH2COO)2]}·2H2O,orthorhombic,space group Pbca with unit cell dimensions a=10.725(3),b=10.851(4),c=21.827(5)Å,V=2540(3)Å3,Z=8,Mr=336.78,Dx=1.76 Mg·m-3,μ=1.81mm-1,F(000)=1376.The structure was solved by di-rect method and refined to R=0.078.The Cu ion is coordinated to one N,two O from two water molecules and two O from two carboxyls to form a square pyramid configuration.
Copper N-(meta-methoxy)-phenyl Iminodiacetate dihydrate,{Cu[CH3OC6H4N(CH2COO)2]}·2H2O,orthorhombic,space group Pbca with unit cell dimensions a=10.725(3),b=10.851(4),c=21.827(5)Å,V=2540(3)Å3,Z=8,Mr=336.78,Dx=1.76 Mg·m-3,μ=1.81mm-1,F(000)=1376.The structure was solved by di-rect method and refined to R=0.078.The Cu ion is coordinated to one N,two O from two water molecules and two O from two carboxyls to form a square pyramid configuration.
1991, 2(6): 465-468
Abstract:
The strong SERS effect was found for p-aminobenzoic acid (PABA) molecules adsorbed on Ag4Fe(CN)6 colloid for the first time.The enhancement factor is 8×107 in estimation.The enhancement mechanism was discussed by studying the influence of ferrocyanide,ferricyanide,thiosulfate,hydrogen per-oxide,sodium chloride or potassium chloride,and pH value on the SERS intensity of PABA in Ag4Fe(CN)6 colloid.
The strong SERS effect was found for p-aminobenzoic acid (PABA) molecules adsorbed on Ag4Fe(CN)6 colloid for the first time.The enhancement factor is 8×107 in estimation.The enhancement mechanism was discussed by studying the influence of ferrocyanide,ferricyanide,thiosulfate,hydrogen per-oxide,sodium chloride or potassium chloride,and pH value on the SERS intensity of PABA in Ag4Fe(CN)6 colloid.
1991, 2(6): 469-470
Abstract:
Adsorption properties of SCO in collophane system has been studied by ESCA.The results indicate that affinity of SCO with magnesium is stronger than that with calcium,and surface conversion is main reason of SCO selectivity falling.
Adsorption properties of SCO in collophane system has been studied by ESCA.The results indicate that affinity of SCO with magnesium is stronger than that with calcium,and surface conversion is main reason of SCO selectivity falling.
1991, 2(6): 471-472
Abstract:
The photoelectrochemical polymerization of aniline was carried out on n-type semiconductor anodes in aqueous acid solution (pH=1).The oxidation behavior was examined.It was noted that,polyaniline was easily obtained even at the potentials more negative than +0.20V (vs.SCE).The probable oxidation mechanism of aniline in this system was proposed.
The photoelectrochemical polymerization of aniline was carried out on n-type semiconductor anodes in aqueous acid solution (pH=1).The oxidation behavior was examined.It was noted that,polyaniline was easily obtained even at the potentials more negative than +0.20V (vs.SCE).The probable oxidation mechanism of aniline in this system was proposed.
1991, 2(6): 473-474
Abstract:
Self-reinforced materials can be obtained by incorporating mesogenic groups into flexible molecular chains.In this paper the crystallization kinetics and mechanisms of phase transitions for sequential block copolyesters(A) synthesized through polycondensation of the mesogenic group 2-methy1-p-phenylene di(4-chloroformyl)
Self-reinforced materials can be obtained by incorporating mesogenic groups into flexible molecular chains.In this paper the crystallization kinetics and mechanisms of phase transitions for sequential block copolyesters(A) synthesized through polycondensation of the mesogenic group 2-methy1-p-phenylene di(4-chloroformyl)
1991, 2(6): 475-478
Abstract:
The polarization result of layer-structured n-InSe in Fe2+/Fe3+ solution was briefly reported.Photoanodic corrosion was observed.A method to determine the thickness of selenium film formed was described,the fraction of photocurrent participating in the corrosion reaction can be approximately estimated.
The polarization result of layer-structured n-InSe in Fe2+/Fe3+ solution was briefly reported.Photoanodic corrosion was observed.A method to determine the thickness of selenium film formed was described,the fraction of photocurrent participating in the corrosion reaction can be approximately estimated.
1991, 2(6): 479-482
Abstract:
PASCA,in conjunction with IR and chemical analysis,has been used to study Al2O3 and Pt/Al2O3 catalytic systems with and without chlorine.In the absence of Cl- ions,Pt,can not interact with any surface sites of Al2O3.This indicates that Cl- ions play a very important role in the interaction between the metal (Pt) and its support (All2O3).Platinum,in form of [PtCl6]=,interacts with the surface sites of Al2O3 by replacing the hydroxyls (OH-) from the surface,resulting in the formation of MSIC (metal-support interaction complex).
PASCA,in conjunction with IR and chemical analysis,has been used to study Al2O3 and Pt/Al2O3 catalytic systems with and without chlorine.In the absence of Cl- ions,Pt,can not interact with any surface sites of Al2O3.This indicates that Cl- ions play a very important role in the interaction between the metal (Pt) and its support (All2O3).Platinum,in form of [PtCl6]=,interacts with the surface sites of Al2O3 by replacing the hydroxyls (OH-) from the surface,resulting in the formation of MSIC (metal-support interaction complex).
1991, 2(6): 483-484
Abstract:
Rhus laccase-catalyzed oxidation of coexistent ferrocene (Fc-H) and K4Fe (CN)6 in the diethylene glycol monobutyl ether/phosphate buffer (V/V 1/4) was studied.We found that Fc-H can promote oxidation of K4Fe (CN)6,and put forward the reaction mechanism.
Rhus laccase-catalyzed oxidation of coexistent ferrocene (Fc-H) and K4Fe (CN)6 in the diethylene glycol monobutyl ether/phosphate buffer (V/V 1/4) was studied.We found that Fc-H can promote oxidation of K4Fe (CN)6,and put forward the reaction mechanism.
1991, 2(6): 485-486
Abstract:
The precursor of LaFeO3 was prepared in alcohol.Nanocrystals of LaFeO3 were synthesized by solid reaction at 550℃ for 2h.XRP,DTA and TEM were used to characterize the samples.Results show that alcohols are better liquid dispersing mediums.The grain size distribution-concentrated and well-dispersed LaFeO3 nanocrystals were obtained by the calcination.
The precursor of LaFeO3 was prepared in alcohol.Nanocrystals of LaFeO3 were synthesized by solid reaction at 550℃ for 2h.XRP,DTA and TEM were used to characterize the samples.Results show that alcohols are better liquid dispersing mediums.The grain size distribution-concentrated and well-dispersed LaFeO3 nanocrystals were obtained by the calcination.
1991, 2(6): 487-488
Abstract:
Crown ether was used as a coating substrate for a piezoelectric crystal to assay toluene vapor,and a reversible and highly sensitive adsorption was observed.
Crown ether was used as a coating substrate for a piezoelectric crystal to assay toluene vapor,and a reversible and highly sensitive adsorption was observed.
1991, 2(6): 489-492
Abstract:
The electrode process of bilirubin/human serum albumin complex studied by in situ circular dichroism electrochemistry has been reported.Circular dichroism spectra of the complex were given at different potentials.An s-shape curve shows that there is a sudden change of bilirubin conformation existing in the process of electrolysis.The mechanism of the circular dichroism spectral changes in electrooxidation process of the complex was proposed.
The electrode process of bilirubin/human serum albumin complex studied by in situ circular dichroism electrochemistry has been reported.Circular dichroism spectra of the complex were given at different potentials.An s-shape curve shows that there is a sudden change of bilirubin conformation existing in the process of electrolysis.The mechanism of the circular dichroism spectral changes in electrooxidation process of the complex was proposed.
1991, 2(6): 493-494
Abstract:
New oscillating reactions with the participation of a tetraaza-macrocyclic Ni (Ⅱ) complex as catalyst in acidic bromate medium are des-cribed.The complex contains the unsaturated macrocyclic ligand 2,4,9,9,11-hehamethyl-1,5,8,12-tetraaza-cyclopentadeca-1,11-diene.
New oscillating reactions with the participation of a tetraaza-macrocyclic Ni (Ⅱ) complex as catalyst in acidic bromate medium are des-cribed.The complex contains the unsaturated macrocyclic ligand 2,4,9,9,11-hehamethyl-1,5,8,12-tetraaza-cyclopentadeca-1,11-diene.
1991, 2(6): 495-496
Abstract:
By using TPD GC,TGA and DTA,we have investigated the dehydrating processes of a set of metal ion exchange montmorillonites.The results show that there can be only one species of water in the montmorilionite,which is different from the view universally accepted at present.
By using TPD GC,TGA and DTA,we have investigated the dehydrating processes of a set of metal ion exchange montmorillonites.The results show that there can be only one species of water in the montmorilionite,which is different from the view universally accepted at present.
1991, 2(6): 497-498
Abstract:
A fiber optic-based Optically Transparent Thin-layer Electrode (OTTLE) is described,which shows the advantages of usefulness in remote sensing,low cell volume and experimental simplicity.
A fiber optic-based Optically Transparent Thin-layer Electrode (OTTLE) is described,which shows the advantages of usefulness in remote sensing,low cell volume and experimental simplicity.
1991, 2(6): 499-500
Abstract:
ZSM-5 type zeolite containing lanthanum was synthesized in hydrothermal system.The structure and physicochemical property of the catalyst were investigated.
ZSM-5 type zeolite containing lanthanum was synthesized in hydrothermal system.The structure and physicochemical property of the catalyst were investigated.
