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1993 Volume 4 Issue 9
1993, 4(9): 753-756
Abstract:
A convenient method for the asymmetric synthesis of 1-aminoalkylphosphonic acids was described.It involved the diastereoselctive alkylation of bicyclic chloromethylphosphonamide derived from (S)-2-ani-linomethylpyrrolidine followed by subsequent conversions leading to amino compounds by Staudinger method.Acid hydrolysis afforded the target molecule in good yield.
A convenient method for the asymmetric synthesis of 1-aminoalkylphosphonic acids was described.It involved the diastereoselctive alkylation of bicyclic chloromethylphosphonamide derived from (S)-2-ani-linomethylpyrrolidine followed by subsequent conversions leading to amino compounds by Staudinger method.Acid hydrolysis afforded the target molecule in good yield.
1993, 4(9): 757-758
Abstract:
A stereoselective and regiospecific synthesis of procursors (2),(4),(6) and (7) of prostacyclin analogues from 2, 3-epoxylbicyclo[3.2.0]hept-6-one (1) are described.
A stereoselective and regiospecific synthesis of procursors (2),(4),(6) and (7) of prostacyclin analogues from 2, 3-epoxylbicyclo[3.2.0]hept-6-one (1) are described.
1993, 4(9): 759-762
Abstract:
Aliphatic α-oxo ketene cyclic dithioacetals 1 were reacted with allyl magnesium bromide to afford the 1, 2-addition products 2.Catalyzed by boron trifluoride etherate, the adducts 2 were etherified by methanol to afford the corresponding methyl ethers 3.This process provides a new method for the protection of the acid sensitive hydroxyl group in 2 under mild condition.
Aliphatic α-oxo ketene cyclic dithioacetals 1 were reacted with allyl magnesium bromide to afford the 1, 2-addition products 2.Catalyzed by boron trifluoride etherate, the adducts 2 were etherified by methanol to afford the corresponding methyl ethers 3.This process provides a new method for the protection of the acid sensitive hydroxyl group in 2 under mild condition.
1993, 4(9): 763-766
Abstract:
Reaction of α-(1H-1, 2, 4-triazol-1-yl) acetophenone with phenyl isothiocyanate in the presence of a base and subsequent alkylation leads to the ketene S, N-acetal (2), (4), (7), (8);thiazolidone (3), thiazolidine (5) and 1, 3-thiazine (6).
Reaction of α-(1H-1, 2, 4-triazol-1-yl) acetophenone with phenyl isothiocyanate in the presence of a base and subsequent alkylation leads to the ketene S, N-acetal (2), (4), (7), (8);thiazolidone (3), thiazolidine (5) and 1, 3-thiazine (6).
1993, 4(9): 767-768
Abstract:
Keeping in view the biological activities of 3-hydroxyisoxazole and cyclic phosphate derivatives, some compounds possessing these two moieties have been synthesized, the structural elucidation of these diastereomers was made depending on spectral analyses.The mechanism could be illustrated by the theories of trigonal bipyramide intermediate and pseudorotation.
Keeping in view the biological activities of 3-hydroxyisoxazole and cyclic phosphate derivatives, some compounds possessing these two moieties have been synthesized, the structural elucidation of these diastereomers was made depending on spectral analyses.The mechanism could be illustrated by the theories of trigonal bipyramide intermediate and pseudorotation.
1993, 4(9): 769-770
Abstract:
A dicarbonyl precursor of 9-hydroxy-cembrene-C, 8-tetrahydropyranoxy-3, 7, 11, 15-tetramethyl-14-oxo-2E, 6E, 10E-hexdecatrienal, was prepared from farnesyl acetate via four steps.
A dicarbonyl precursor of 9-hydroxy-cembrene-C, 8-tetrahydropyranoxy-3, 7, 11, 15-tetramethyl-14-oxo-2E, 6E, 10E-hexdecatrienal, was prepared from farnesyl acetate via four steps.
1993, 4(9): 771-774
Abstract:
3-Methylthio-5-hydroxy-1, 2, 4-triazine (1c) reacted with substituted benzenesulfonyl chloride to give 3-methylthio-5-oxy-1, 2, 4-triazin-6-yl pyridinium betaine (4) in anhydrous pyridine.But when NaOH/H2O/CH3COCH3 or NaOH/CH3OH were used as reactant and solvent, 3-methylthio-4-substituted benzenesulfonyl-5-oxo-6-hydroxy-1, 4, 5, 6-tetrahydro-1, 2, 4-triazine (6) or 1-tosyl-3-methylthio-5-oxo-6-methyloxy-1, 4, 5, 6-tetrahydro-1, 2, 4-triazine (7) was obtained respectively.The above reactions show anomalous properties of nucleophilic attack on 6-carbon in 1, 2, 4-triazine ring.
3-Methylthio-5-hydroxy-1, 2, 4-triazine (1c) reacted with substituted benzenesulfonyl chloride to give 3-methylthio-5-oxy-1, 2, 4-triazin-6-yl pyridinium betaine (4) in anhydrous pyridine.But when NaOH/H2O/CH3COCH3 or NaOH/CH3OH were used as reactant and solvent, 3-methylthio-4-substituted benzenesulfonyl-5-oxo-6-hydroxy-1, 4, 5, 6-tetrahydro-1, 2, 4-triazine (6) or 1-tosyl-3-methylthio-5-oxo-6-methyloxy-1, 4, 5, 6-tetrahydro-1, 2, 4-triazine (7) was obtained respectively.The above reactions show anomalous properties of nucleophilic attack on 6-carbon in 1, 2, 4-triazine ring.
1993, 4(9): 775-778
Abstract:
Here reported the ester exchange of DIPP-His with primary alcohols and found that the rate of this reaction was increased as the increment of the carbon chain of alcohols used.
Here reported the ester exchange of DIPP-His with primary alcohols and found that the rate of this reaction was increased as the increment of the carbon chain of alcohols used.
1993, 4(9): 779-782
Abstract:
Molecular simulation technique was used in an examination of the possibilities of chain packing in the crystalline state for poly (p-phenylene benzobisthiazole).It has been found that one reason of hardly forming very ordered crystal of the polymer is the existence of so many stable positions of interchain interaction along chain axis.
Molecular simulation technique was used in an examination of the possibilities of chain packing in the crystalline state for poly (p-phenylene benzobisthiazole).It has been found that one reason of hardly forming very ordered crystal of the polymer is the existence of so many stable positions of interchain interaction along chain axis.
1993, 4(9): 783-784
Abstract:
On the basis of spectral analysis combined with preparation of derivatives, nervosin D was identified as ent-1α, 6β, 7β, 11α, 15β-pentahydro-xy-7α, 20-epoxykaur-16-ene.
On the basis of spectral analysis combined with preparation of derivatives, nervosin D was identified as ent-1α, 6β, 7β, 11α, 15β-pentahydro-xy-7α, 20-epoxykaur-16-ene.
1993, 4(9): 785-786
Abstract:
Two new iridoid glycosides, plicatoside A and plicatoside B, were isolated from whole plants of Pedicularis plicata.Their structures were identified as 2'-O-β-D-glucosyl ixoroside and 4'-O-β-D-xylosyl mussaenoside by means of chemical evidence and spectral data.
Two new iridoid glycosides, plicatoside A and plicatoside B, were isolated from whole plants of Pedicularis plicata.Their structures were identified as 2'-O-β-D-glucosyl ixoroside and 4'-O-β-D-xylosyl mussaenoside by means of chemical evidence and spectral data.
1993, 4(9): 787-790
Abstract:
A new Mutactimycin group antibiotic (XF-1) was isolated from the mycelium of Streptomyces sp.80-115 and its structure has been determined on the basis of its spectroscopical and chemical properties.XF-1 showed active against some Gram positive bacteria.
A new Mutactimycin group antibiotic (XF-1) was isolated from the mycelium of Streptomyces sp.80-115 and its structure has been determined on the basis of its spectroscopical and chemical properties.XF-1 showed active against some Gram positive bacteria.
1993, 4(9): 791-792
Abstract:
Degradation reaction of doxycycline or methacycline was carried out in KOH solution and intense fluorescence was obtained.A degradation mechanism of doxycycline or methacycline was suggested.
Degradation reaction of doxycycline or methacycline was carried out in KOH solution and intense fluorescence was obtained.A degradation mechanism of doxycycline or methacycline was suggested.
1993, 4(9): 793-794
Abstract:
The graphtheory method is used to enumerate the numbers of constitutions, configurations, chiral and achiral configurations of substituted crown ethers.The numerical results are tabulated.
The graphtheory method is used to enumerate the numbers of constitutions, configurations, chiral and achiral configurations of substituted crown ethers.The numerical results are tabulated.
1993, 4(9): 795-796
Abstract:
The intersection point rule for homologues in gas chromatography was discovered many years ago[1], now more and more application and development are occurring in recent years[2-6], but there are few systemic theoretical studies.In this paper, based on the basic equation of retention values in gas chromatography, we prove the intersection point rule of homologues from mathematics, study the factors affecting intersection point position, give the physical meaning of intersection point, and explain the experimental rules in references.
The intersection point rule for homologues in gas chromatography was discovered many years ago[1], now more and more application and development are occurring in recent years[2-6], but there are few systemic theoretical studies.In this paper, based on the basic equation of retention values in gas chromatography, we prove the intersection point rule of homologues from mathematics, study the factors affecting intersection point position, give the physical meaning of intersection point, and explain the experimental rules in references.
1993, 4(9): 797-800
Abstract:
Reactions of C60 with Si(CH3)nCl4-n (n=2, 3) in the ion source of the mass spectrometer have been studied.The corresponding adduct ions[C60Si(CH3)mCl3-m]+(m=1, 2, 3), [C60SiCl]+ and [C60CH3]+ were observed and their possible structures were discussed.The results indicated that C60 is very reactive to electrophiles in the gas phase.
Reactions of C60 with Si(CH3)nCl4-n (n=2, 3) in the ion source of the mass spectrometer have been studied.The corresponding adduct ions[C60Si(CH3)mCl3-m]+(m=1, 2, 3), [C60SiCl]+ and [C60CH3]+ were observed and their possible structures were discussed.The results indicated that C60 is very reactive to electrophiles in the gas phase.
1993, 4(9): 801-804
Abstract:
The mathematical model for the thermokinetics of irreversible consecutive first order reactions has been suggested, which was used for the calculation of rate constants and molar enthalpies of the two consecutive steps.And its validity has been verified by the experimental results.
The mathematical model for the thermokinetics of irreversible consecutive first order reactions has been suggested, which was used for the calculation of rate constants and molar enthalpies of the two consecutive steps.And its validity has been verified by the experimental results.
1993, 4(9): 805-808
Abstract:
We compute the thermodynamic and the kinetic properties for the reaction:HCOCN→HCH+CO using the statistical theory and the transition-state theory.The equilibrium constants and the rate coefficients of this reaction are also reported here, and the half lives of formyl cyanide at different temperatures are first estimated in this work.
We compute the thermodynamic and the kinetic properties for the reaction:HCOCN→HCH+CO using the statistical theory and the transition-state theory.The equilibrium constants and the rate coefficients of this reaction are also reported here, and the half lives of formyl cyanide at different temperatures are first estimated in this work.
1993, 4(9): 809-812
Abstract:
The stability constants of the binary complexes of Cu2+ with isoquinoline and benzimidazole as well as the ternary complexes of Cu(ATP) with the same ligands have been measured in aqueous solution spectrophotometrically and a strong stacking interaction between the heteroaromatic ring of the ligands and the purine moiety of ATP has been found.The fact of this stacking interaction is much stronger than that in the systems of Cu(ATP) with pyridine and imidazole shows that the stacking interaction increases with the size of the heteroaromatic ring of the ligands.
The stability constants of the binary complexes of Cu2+ with isoquinoline and benzimidazole as well as the ternary complexes of Cu(ATP) with the same ligands have been measured in aqueous solution spectrophotometrically and a strong stacking interaction between the heteroaromatic ring of the ligands and the purine moiety of ATP has been found.The fact of this stacking interaction is much stronger than that in the systems of Cu(ATP) with pyridine and imidazole shows that the stacking interaction increases with the size of the heteroaromatic ring of the ligands.
1993, 4(9): 813-814
Abstract:
Single quantum wells (SQWs) of GaAs/AlxGa1-xAs have been investigated as photoelectrodes in photoelectrochemical cells.Structured photocurrent spectra for well widths of 50Å and 100Å SQWs were obtained in nonaqueous solution.The dependence of structured photocurrent spectra on electrode potential were exhibited.The quantum yield was higher in SQW with 100Å well compared to 50Å well.
Single quantum wells (SQWs) of GaAs/AlxGa1-xAs have been investigated as photoelectrodes in photoelectrochemical cells.Structured photocurrent spectra for well widths of 50Å and 100Å SQWs were obtained in nonaqueous solution.The dependence of structured photocurrent spectra on electrode potential were exhibited.The quantum yield was higher in SQW with 100Å well compared to 50Å well.
1993, 4(9): 815-816
Abstract:
The kinetics of interracial processes of CdSe thin film electrode before and after surface modification of 1, 1'-di linolene ferrocenyl L-B films have been studied in K4Fe(CN)6 solution by Intensity Modulated Photocurrent Spectroscopy (IMPS).Potential dependence of surface state relaxation time (Ts), steady state photocurrent (Is), collection coefficient of minority carriers (Go), rate constant of photocorrosion (Kcr), and density of surface state (Nss) were determined in terms of frequency response analysis of IMPS plots.
The kinetics of interracial processes of CdSe thin film electrode before and after surface modification of 1, 1'-di linolene ferrocenyl L-B films have been studied in K4Fe(CN)6 solution by Intensity Modulated Photocurrent Spectroscopy (IMPS).Potential dependence of surface state relaxation time (Ts), steady state photocurrent (Is), collection coefficient of minority carriers (Go), rate constant of photocorrosion (Kcr), and density of surface state (Nss) were determined in terms of frequency response analysis of IMPS plots.
1993, 4(9): 817-820
Abstract:
The formation of color centers in BaFCl:Eu2+ crystal is studied in more detail and further evidence for FA centers in BaFCl:Eu2+ is reported.The creation of color centers in BaFCl:Eu2+ may be devided into three stages.Under long time X-irradiation beyond stage 1, the concentration of FA centers depends linearly on the nth (n=1, 2 or 3) power of F center concentration.While under short time X-irradiation within stage 1, the concentration dependence of FA centers on F center is complex.Simple centers are easier to create than complex centers.Possible mechanisms for color centers formation in BaFCl:Eu2+ are also proposed and discussed.
The formation of color centers in BaFCl:Eu2+ crystal is studied in more detail and further evidence for FA centers in BaFCl:Eu2+ is reported.The creation of color centers in BaFCl:Eu2+ may be devided into three stages.Under long time X-irradiation beyond stage 1, the concentration of FA centers depends linearly on the nth (n=1, 2 or 3) power of F center concentration.While under short time X-irradiation within stage 1, the concentration dependence of FA centers on F center is complex.Simple centers are easier to create than complex centers.Possible mechanisms for color centers formation in BaFCl:Eu2+ are also proposed and discussed.
1993, 4(9): 821-824
Abstract:
A spinel oxide NiCo204 prepared by thermal decomposition is of very high activity for the oxygen evolution reaction (OER) in alkaline solution.The oxygen evolution overpotential on NiCo204 is 0.252-0.262V in 10 M NaOH solution at 343K and current density 100 mAcm-2.
A spinel oxide NiCo204 prepared by thermal decomposition is of very high activity for the oxygen evolution reaction (OER) in alkaline solution.The oxygen evolution overpotential on NiCo204 is 0.252-0.262V in 10 M NaOH solution at 343K and current density 100 mAcm-2.
1993, 4(9): 825-826
Abstract:
The process of emulsifier-free copolymerization of the Styrene-Butyl Acrylate-K2S2O8-water in the presence of Barium Sulfate (BS) powder was investigated under varied conditions within the range of BS powder quantity, initiator concentration and reaction temperature.Experimental results showed that the rate of polymerization is proportional to 0.3-power of the BS quantity and 1.3-power of the initiator concentration.There is a linear relationship of 2/3-power for the conversion and time.A process for the polymerization is propose to explain the experimental results.
The process of emulsifier-free copolymerization of the Styrene-Butyl Acrylate-K2S2O8-water in the presence of Barium Sulfate (BS) powder was investigated under varied conditions within the range of BS powder quantity, initiator concentration and reaction temperature.Experimental results showed that the rate of polymerization is proportional to 0.3-power of the BS quantity and 1.3-power of the initiator concentration.There is a linear relationship of 2/3-power for the conversion and time.A process for the polymerization is propose to explain the experimental results.
1993, 4(9): 827-828
Abstract:
A new method for the rapid separation of gangliosides (GLS) by capillary electrophoresis (CE) is described which is based on the use of β—cyclodextrin (β—CD) as buffer additive.The effects of β—CD concentration, pH, electrolyte composition were discussed.Under optimum conditions, the complete separation of a mixture of GM1, GD1a, GD1b and GT1b was obtained within 5 min.
A new method for the rapid separation of gangliosides (GLS) by capillary electrophoresis (CE) is described which is based on the use of β—cyclodextrin (β—CD) as buffer additive.The effects of β—CD concentration, pH, electrolyte composition were discussed.Under optimum conditions, the complete separation of a mixture of GM1, GD1a, GD1b and GT1b was obtained within 5 min.
1993, 4(9): 829-830
Abstract:
In-situ time-resolved Raman spectroscopy (TRRS) has been applied on studies of electrochemical adsorption of thiocyanate at silver electrode during potential cycles and potential step.It is shown that some dynamic information about the adsorption and desorption processes can be obtained.
In-situ time-resolved Raman spectroscopy (TRRS) has been applied on studies of electrochemical adsorption of thiocyanate at silver electrode during potential cycles and potential step.It is shown that some dynamic information about the adsorption and desorption processes can be obtained.
1993, 4(9): 831-832
Abstract:
A novel method for preparing metalllzed film has been studied.The reduction process and properties of the poly (vinyl alcohol) (PVA) were probed by several analytic means.According to the etudies, a mechanism for the polymer surface reduction metallization was proposed and proved.
A novel method for preparing metalllzed film has been studied.The reduction process and properties of the poly (vinyl alcohol) (PVA) were probed by several analytic means.According to the etudies, a mechanism for the polymer surface reduction metallization was proposed and proved.
1993, 4(9): 833-836
Abstract:
Triheptyl cellulose/ethyl cellulose (3/97) binary blend membranes were prepared from tetrahydrofuran, chloroform and dichloromethane solutions and their air separation capabitities were studied at different temperatures.With increasing temperature from 25 to 85℃, the flux QOEA of O2-enriched air (OEA), O2 permselectivity and the O2 concentration Yo2 in the OEA all increase.The membranes show a unique trend in their Yo2~QOEA relationship, that is, the air separation capability increases simultaneously with the OEA permeation capability.The magnitudes of QOEA and Yo2 for 17μm-thick membrane after the testing time of 36hours at 70℃ are 5×10cm3 (STP)/s·cm-2 and 37.6%, respectively.The air separation capability depends slightly on membrane forming solvents.
Triheptyl cellulose/ethyl cellulose (3/97) binary blend membranes were prepared from tetrahydrofuran, chloroform and dichloromethane solutions and their air separation capabitities were studied at different temperatures.With increasing temperature from 25 to 85℃, the flux QOEA of O2-enriched air (OEA), O2 permselectivity and the O2 concentration Yo2 in the OEA all increase.The membranes show a unique trend in their Yo2~QOEA relationship, that is, the air separation capability increases simultaneously with the OEA permeation capability.The magnitudes of QOEA and Yo2 for 17μm-thick membrane after the testing time of 36hours at 70℃ are 5×10cm3 (STP)/s·cm-2 and 37.6%, respectively.The air separation capability depends slightly on membrane forming solvents.
1993, 4(9): 837-840
Abstract:
The spectroscopic properties for a recently synthesized hetero-metallobinuclear complex Ru(bpy)2 (bpy-cyclam-Ni)4+ (3) and its related complexes 1 and 2 were investigated by UV-vis and emission spectral methods.A drastic quenching offluorescence from the Ru(bpy)32+ subunit by the covalently attached quencher subunit Ni(cyclam)2+ was observed for complex 3, and the mechanism was discussed.
The spectroscopic properties for a recently synthesized hetero-metallobinuclear complex Ru(bpy)2 (bpy-cyclam-Ni)4+ (3) and its related complexes 1 and 2 were investigated by UV-vis and emission spectral methods.A drastic quenching offluorescence from the Ru(bpy)32+ subunit by the covalently attached quencher subunit Ni(cyclam)2+ was observed for complex 3, and the mechanism was discussed.
1993, 4(9): 841-844
Abstract:
(CH3OCH2CH2C5H4)2LnI (Ln=La, Nd) complexes have beensynthesized by the reaction between NaI and [(CH3OCH2CH2C5H4)2LnCl]2 in THF; A single crystal X-ray study has shown that the lanthanum complex is an unsolvated monomer with lanthanum (Ⅲ) in a trigonal bipyramidal coordination geometry if the cyclopentadienyl ring is regarded as occupying a single polyhedral vertex.
(CH3OCH2CH2C5H4)2LnI (Ln=La, Nd) complexes have beensynthesized by the reaction between NaI and [(CH3OCH2CH2C5H4)2LnCl]2 in THF; A single crystal X-ray study has shown that the lanthanum complex is an unsolvated monomer with lanthanum (Ⅲ) in a trigonal bipyramidal coordination geometry if the cyclopentadienyl ring is regarded as occupying a single polyhedral vertex.
1993, 4(9): 845-846
Abstract:
The present paper covers the synthesis of ZSM-35 molecular sieve with 1, 6-hexanediamine as templating agent, the influence of the synthesis conditions, and a discussion concerning the crystal structures of the products.
The present paper covers the synthesis of ZSM-35 molecular sieve with 1, 6-hexanediamine as templating agent, the influence of the synthesis conditions, and a discussion concerning the crystal structures of the products.
