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1993 Volume 4 Issue 4
1993, 4(4): 283-284
Abstract:
(±)Lespedezaflavanone D,8,5'-di(γ,γ-dimethylallyl)-5,7,2',4'-tetrahydroxyflavanone,has been synthesized by the condensation of 4,6-dimethoxymethoxy-3-(γ,γ-dimethylallyl)-2-hydroxyacetophenone with 2,4-dimethoxymethoxy-5-(γ,γ-dimethylallyl) benzaldehydc followed by cyclization and demethoxymethylation.
(±)Lespedezaflavanone D,8,5'-di(γ,γ-dimethylallyl)-5,7,2',4'-tetrahydroxyflavanone,has been synthesized by the condensation of 4,6-dimethoxymethoxy-3-(γ,γ-dimethylallyl)-2-hydroxyacetophenone with 2,4-dimethoxymethoxy-5-(γ,γ-dimethylallyl) benzaldehydc followed by cyclization and demethoxymethylation.
1993, 4(4): 285-286
Abstract:
α-fructofuranosides were stereospecifically synthesized from 2-O-Ac-1,3,4,6-O-tetra-benzoylfructose by employing TMSOTf as a catalyst.Meanwhile,one diastereoisomer derivative of sucrose and two of fructan oligomers were synthesized.The structure of all products were confirmed by 13C-NMR and 1H-NMR spectra.
α-fructofuranosides were stereospecifically synthesized from 2-O-Ac-1,3,4,6-O-tetra-benzoylfructose by employing TMSOTf as a catalyst.Meanwhile,one diastereoisomer derivative of sucrose and two of fructan oligomers were synthesized.The structure of all products were confirmed by 13C-NMR and 1H-NMR spectra.
1993, 4(4): 287-288
Abstract:
The mono-α-nitronyl nitroxide substituted diacetylene was synthesized and its structure was established by EA,FAB-MS,IR,ESR and x-ray diffraction analysis.Using the Extracting Sample Magnetometer,its magnetic properties was investigated,and the results indicate that this compound possesses antiferromagnetic properties.
The mono-α-nitronyl nitroxide substituted diacetylene was synthesized and its structure was established by EA,FAB-MS,IR,ESR and x-ray diffraction analysis.Using the Extracting Sample Magnetometer,its magnetic properties was investigated,and the results indicate that this compound possesses antiferromagnetic properties.
1993, 4(4): 289-290
Abstract:
4-Amino-4-deoxy-4'-demethylepipodophyllotoxin has been directly synthesized from 4'-demethylepipodophyllotoxin and HN3 in the presence of BF3·Et2O,followed by hydrogenation with palladium on charcoal as catalyst.
4-Amino-4-deoxy-4'-demethylepipodophyllotoxin has been directly synthesized from 4'-demethylepipodophyllotoxin and HN3 in the presence of BF3·Et2O,followed by hydrogenation with palladium on charcoal as catalyst.
1993, 4(4): 291-294
Abstract:
The key intermediate 5 for synthesis of the contragestationally active diterpenoid grandiflorenic acid (1) and its analogues 2 and 3 was prepared and an acetyl transposition reaction occurred in the SeO2 oxidation of 8.
The key intermediate 5 for synthesis of the contragestationally active diterpenoid grandiflorenic acid (1) and its analogues 2 and 3 was prepared and an acetyl transposition reaction occurred in the SeO2 oxidation of 8.
1993, 4(4): 295-296
Abstract:
3-Butylidene-5-hydroxyphthalide(1) was prepared from 4-hydroxybenzoic acid (2).
3-Butylidene-5-hydroxyphthalide(1) was prepared from 4-hydroxybenzoic acid (2).
1993, 4(4): 297-298
Abstract:
The first synthesis of squarnosamide,a new compound isolated from Annona squamosa,was achieved in seven steps.The over all yield was 14%.The compound was identified by 1H,13CNMR and MS.
The first synthesis of squarnosamide,a new compound isolated from Annona squamosa,was achieved in seven steps.The over all yield was 14%.The compound was identified by 1H,13CNMR and MS.
1993, 4(4): 299-302
Abstract:
2-(1,3-dithian-2-ylidene)-1-arylethenones 3 Via chemoselective 1,2-addition with methyl,ethyl,phenyl,allyl,and benzyl Grignard reagents afforded the corresponding alcohols (4).Catalyzing by silica gel,the alcohols 4 were converted to the aryl.ketones (5).The entire process represent a demethylation-alkylation reaction of acetophenones.The mechanism of reaction are proposed and the structure requirement for the conversion of the alcohols (4) was discussed.
2-(1,3-dithian-2-ylidene)-1-arylethenones 3 Via chemoselective 1,2-addition with methyl,ethyl,phenyl,allyl,and benzyl Grignard reagents afforded the corresponding alcohols (4).Catalyzing by silica gel,the alcohols 4 were converted to the aryl.ketones (5).The entire process represent a demethylation-alkylation reaction of acetophenones.The mechanism of reaction are proposed and the structure requirement for the conversion of the alcohols (4) was discussed.
1993, 4(4): 303-306
Abstract:
Pentafluorophenyl diphenylphosphate was found to be a novel convenient coupling reagent for the peptide synthesis with several advantages.Higher yield and lower racemization were found with this reagent than DCCI.
Pentafluorophenyl diphenylphosphate was found to be a novel convenient coupling reagent for the peptide synthesis with several advantages.Higher yield and lower racemization were found with this reagent than DCCI.
1993, 4(4): 307-310
Abstract:
Solid superacid perfluorooctanesulfonic acid (POSA) catalyzed Friedel-Crafts alkylation of aromatic hydrocarbons with olefins in gas-liquid phase.The alkylations gave good yields with simple operation and easy work up.The amount of the catalyst used in the reactions was small and could be reused.The optimum temperature of the reactions and the effect of the amount of the catalyst used in the reactions are also discussed.
Solid superacid perfluorooctanesulfonic acid (POSA) catalyzed Friedel-Crafts alkylation of aromatic hydrocarbons with olefins in gas-liquid phase.The alkylations gave good yields with simple operation and easy work up.The amount of the catalyst used in the reactions was small and could be reused.The optimum temperature of the reactions and the effect of the amount of the catalyst used in the reactions are also discussed.
1993, 4(4): 311-312
Abstract:
A new Schiff base diol,4,4'-[3-methoxy-4-(2-hydroxy)-ethoxy] azomethine biphenyl (MHAMB),was synthesized,which was copolynerized with PEC-600 and TDI to obtain a blook polyurethane.The monomer and the polymer were charaoterized by eaploying IR,NMR and elemental analysis,Liquid crystallline phase transitions were studied by polarized aiorograph.
A new Schiff base diol,4,4'-[3-methoxy-4-(2-hydroxy)-ethoxy] azomethine biphenyl (MHAMB),was synthesized,which was copolynerized with PEC-600 and TDI to obtain a blook polyurethane.The monomer and the polymer were charaoterized by eaploying IR,NMR and elemental analysis,Liquid crystallline phase transitions were studied by polarized aiorograph.
1993, 4(4): 313-314
Abstract:
Some telluronium salts react easily with 1,4-bis(3-substituted phenyl-3-oxo-1-propenyl) benzene and 1,5-disubstituted phenyl-1,4-pentadien-3-one to afford derivatives of biscyclopropanes in 61.8-88.8% yield.
Some telluronium salts react easily with 1,4-bis(3-substituted phenyl-3-oxo-1-propenyl) benzene and 1,5-disubstituted phenyl-1,4-pentadien-3-one to afford derivatives of biscyclopropanes in 61.8-88.8% yield.
1993, 4(4): 315-316
Abstract:
In the presence of catalytic amounts of tellurium,aryl chloroacetates can be cleaved by sodium borohydride and regenerate parent phenols in good yields.
In the presence of catalytic amounts of tellurium,aryl chloroacetates can be cleaved by sodium borohydride and regenerate parent phenols in good yields.
1993, 4(4): 317-318
Abstract:
α-Aryl-α-cyanosulfones are prepared under mild conditions with good yields by using palladium-catalyzed coupling reaction between aryl halides and α-cyanosulfones in the presence of phase transfer catalyst.
α-Aryl-α-cyanosulfones are prepared under mild conditions with good yields by using palladium-catalyzed coupling reaction between aryl halides and α-cyanosulfones in the presence of phase transfer catalyst.
1993, 4(4): 319-320
Abstract:
Direct hydroxylation of benzene catalyzed by vanadium-containing heteropoly compounds with Keggin or Dawson structure has been investigated.The effects of several factors upon the hydroxylation reaction have also been examined.It is indicated that the highest yield of phenol reached 76% (based on H,O,) with 99.4~100% selectivity.
Direct hydroxylation of benzene catalyzed by vanadium-containing heteropoly compounds with Keggin or Dawson structure has been investigated.The effects of several factors upon the hydroxylation reaction have also been examined.It is indicated that the highest yield of phenol reached 76% (based on H,O,) with 99.4~100% selectivity.
1993, 4(4): 321-322
Abstract:
Two new D/E trans-5d-cevanine alkaloids,Dongbernine and Dongbeirine,have been isolated from Fritillaria thunbergii Miq.var.chekiangensis together with six known compounds,peimine,peiminine,isoverticine,verticindiol,B-sitosterol daucoterol.
Two new D/E trans-5d-cevanine alkaloids,Dongbernine and Dongbeirine,have been isolated from Fritillaria thunbergii Miq.var.chekiangensis together with six known compounds,peimine,peiminine,isoverticine,verticindiol,B-sitosterol daucoterol.
1993, 4(4): 323-326
Abstract:
Two new eremophilane derivatives and one new nor-sesquiterpene were isolated from Ligularia veitchiana.Their structures were elucidated by spectroscopic methods and 2D-NMR techniques and shown to be 1β,10β-epoxy-6β-(2'-semialdehyde acetal hydroxymethylacryloyloxy)-8β-ethoxy-eremophil-7(11)-en-12,8α-olide(1),1β-hydroxy-Δ6,Δ9-8-oxo-eremophil-(12)-oic-acid (2) and 1β-hydroxy-Δ6,Δ9-8-oxo-11-nor-11-hydroxyeremophiladiene(3).
Two new eremophilane derivatives and one new nor-sesquiterpene were isolated from Ligularia veitchiana.Their structures were elucidated by spectroscopic methods and 2D-NMR techniques and shown to be 1β,10β-epoxy-6β-(2'-semialdehyde acetal hydroxymethylacryloyloxy)-8β-ethoxy-eremophil-7(11)-en-12,8α-olide(1),1β-hydroxy-Δ6,Δ9-8-oxo-eremophil-(12)-oic-acid (2) and 1β-hydroxy-Δ6,Δ9-8-oxo-11-nor-11-hydroxyeremophiladiene(3).
1993, 4(4): 327-330
Abstract:
The CIDNP observations indicated that photoreaction of methylfurans with chloranil resulted not only furylmethyl hydroxyphenyl ethers via radical pairs but induced furyl radical isomerization to the derivatives of cyclopropene,propadiene and pyran.
The CIDNP observations indicated that photoreaction of methylfurans with chloranil resulted not only furylmethyl hydroxyphenyl ethers via radical pairs but induced furyl radical isomerization to the derivatives of cyclopropene,propadiene and pyran.
1993, 4(4): 331-334
Abstract:
The photoreactivity of some phthalimides was tested by CIDNP studies on the reactions with triethylamine.
The photoreactivity of some phthalimides was tested by CIDNP studies on the reactions with triethylamine.
1993, 4(4): 335-338
Abstract:
An NMR study on the kinetics of photoisomerization of some important 1,2-disubstituted ethylenes are presented in this study.
An NMR study on the kinetics of photoisomerization of some important 1,2-disubstituted ethylenes are presented in this study.
1993, 4(4): 339-342
Abstract:
A novel triad system zinc phthalocyanine-viologen-ferrocene has been synthesized.Photoinduced intramolecular electron transfer in the new triad system was investigated by fluorescence quenching experiment and nanosecond flash photolysis technique,giving a final long-living chargeseparated state.A mechanism of two-step charge separation was suggested.
A novel triad system zinc phthalocyanine-viologen-ferrocene has been synthesized.Photoinduced intramolecular electron transfer in the new triad system was investigated by fluorescence quenching experiment and nanosecond flash photolysis technique,giving a final long-living chargeseparated state.A mechanism of two-step charge separation was suggested.
1993, 4(4): 343-346
Abstract:
A method for the analysis of monosaccharides derived from glycoproteins and glycolipids was described using the newly developed technique of capillary zone electrophoresis (CZE).It is found that,at ca.0.5-5 nL injection,CZE can offer a high resolution of most monoses from glycoprotein and glycolipids.A mixture of amino-and non-aminomonosaccharides,which is difficult to separate with chromatographic methods,was separated completely by CZE in borate buffer after the monosaccharides were derivatized with 1-naphthylamine.
A method for the analysis of monosaccharides derived from glycoproteins and glycolipids was described using the newly developed technique of capillary zone electrophoresis (CZE).It is found that,at ca.0.5-5 nL injection,CZE can offer a high resolution of most monoses from glycoprotein and glycolipids.A mixture of amino-and non-aminomonosaccharides,which is difficult to separate with chromatographic methods,was separated completely by CZE in borate buffer after the monosaccharides were derivatized with 1-naphthylamine.
1993, 4(4): 347-350
Abstract:
An Eastman-AQ/Ni(Ⅱ) chemically modified electrode (CME) produced by "double coating steps" deposition of Eastman-AQ/Ni(Ⅱ) film and Ni(Ⅱ)-coating crystalline species onto glassy carbon instead of metallic nickel electrode exhibited stable electrocatalytic oxidation of numerous α-hydrogen compounds including carbohydrates,amines and amino acids.Determination of glucose in FIA on the CME,the linear response concentration range was bstween 1.0×10-5 and 5.0×10-2 mol/L and the detection limit was 5.0×10-6mol/L.The stability of the CME was adequate for routine quantitative application.
An Eastman-AQ/Ni(Ⅱ) chemically modified electrode (CME) produced by "double coating steps" deposition of Eastman-AQ/Ni(Ⅱ) film and Ni(Ⅱ)-coating crystalline species onto glassy carbon instead of metallic nickel electrode exhibited stable electrocatalytic oxidation of numerous α-hydrogen compounds including carbohydrates,amines and amino acids.Determination of glucose in FIA on the CME,the linear response concentration range was bstween 1.0×10-5 and 5.0×10-2 mol/L and the detection limit was 5.0×10-6mol/L.The stability of the CME was adequate for routine quantitative application.
1993, 4(4): 351-352
Abstract:
A method for locating double bond in hexadecenyl acetates has been developed by analyzing the mass spectral patterns on a fuzzy classification.The procedure was tested with the spectra of Δ2- to Δ15-isomers and the original double-bond position in these acetates was located unambiguously.
A method for locating double bond in hexadecenyl acetates has been developed by analyzing the mass spectral patterns on a fuzzy classification.The procedure was tested with the spectra of Δ2- to Δ15-isomers and the original double-bond position in these acetates was located unambiguously.
1993, 4(4): 353-354
Abstract:
The activity of the Ab-bound enzyme (HRP) changed after immunochemical reaction,and can be indicated by a sensitive fluorimetric kinetic method.The finding set the stage for developing sensitive homogeneous immunoassay.AFP was measured as an example.
The activity of the Ab-bound enzyme (HRP) changed after immunochemical reaction,and can be indicated by a sensitive fluorimetric kinetic method.The finding set the stage for developing sensitive homogeneous immunoassay.AFP was measured as an example.
1993, 4(4): 355-358
Abstract:
An in-situ optically transparent thin-layer microscopic FTIR spectroelectrochemical cell was constructed.Using this cell,we characterize a concentrationdistance profile in the electrochemical diffusion thin-layer by in-situ adjusting the focal point at different distances to the electrode surface.
An in-situ optically transparent thin-layer microscopic FTIR spectroelectrochemical cell was constructed.Using this cell,we characterize a concentrationdistance profile in the electrochemical diffusion thin-layer by in-situ adjusting the focal point at different distances to the electrode surface.
1993, 4(4): 359-360
Abstract:
In a supporting electrolyte containing 0.6mol/L H2SO4,a sensitivity derivative wave of 2-AES is formed by oscillopolarography.The peak potential is-1.01V (vs.SCE),The change of peak height with the concentration of 2-AES is linear in the range from 3.0×10-7 to 8.0×10-6mol/L.The detection limit is 1.0×10-7mol/L.The electrode reaction mechanism is discussed.
In a supporting electrolyte containing 0.6mol/L H2SO4,a sensitivity derivative wave of 2-AES is formed by oscillopolarography.The peak potential is-1.01V (vs.SCE),The change of peak height with the concentration of 2-AES is linear in the range from 3.0×10-7 to 8.0×10-6mol/L.The detection limit is 1.0×10-7mol/L.The electrode reaction mechanism is discussed.
1993, 4(4): 361-362
Abstract:
Surface-enhanced Raman Spectroscopy (SERS) has been used to characterize hurnic substances.By using HNO3-roughened silver foils as the enhancing surface,both fluorescence quenching and strong SERS signals have been observed at the same time.The results obtained herein show that SERS is a particularly sensitive and highly selective technique for the characterization of humic substances in the environment.
Humic substances axe receiving ever-inereasing attention because of their importance in the environment.Very recently,we have reported the first successful application of Raman spectroscopy for characterizing humic substances.In this present paper,the application of surface-enhanced Raman spectroscopy (SERS) for humic substances has further been investigated.To our knowledge,no such studies have previously beenreported.The results obtained herein dearly demonstrate that SERS has a great deal of promise as ananalytical method for "In Situ" characterizing humic substances in the environment.
Surface-enhanced Raman Spectroscopy (SERS) has been used to characterize hurnic substances.By using HNO3-roughened silver foils as the enhancing surface,both fluorescence quenching and strong SERS signals have been observed at the same time.The results obtained herein show that SERS is a particularly sensitive and highly selective technique for the characterization of humic substances in the environment.
Humic substances axe receiving ever-inereasing attention because of their importance in the environment.Very recently,we have reported the first successful application of Raman spectroscopy for characterizing humic substances.In this present paper,the application of surface-enhanced Raman spectroscopy (SERS) for humic substances has further been investigated.To our knowledge,no such studies have previously beenreported.The results obtained herein dearly demonstrate that SERS has a great deal of promise as ananalytical method for "In Situ" characterizing humic substances in the environment.
1993, 4(4): 363-365
Abstract:
Sublimed D-,L-,and DL-leucine under vacuum were subjected to 60Co γ-irradiation with different doses.The enantiomeric compositions of samples were determined by chirasilval capillary column gas chromatography,and the relative yields of radiolytic products (H2,CO2 and NH3) were measured by packed column gas chromatography.The obtained data showed the peak area ratios D/L of DL-leucine after different absorbed doses of irradiation are all the same as that of samples with no irradiation,within the limit of error.So are the ratios for the separately irradiated D-and L-leuicne.This suggests that no asymmetric decomposition was found.The relative yields D/L of radiolytic products (H2,CO2 and NH3) arevery close to 1.00,indicating that the D-leucine cleavage rate was the same with that of the L-leucine.From the view of dissipative structure,an explanation for the result was presented.
Sublimed D-,L-,and DL-leucine under vacuum were subjected to 60Co γ-irradiation with different doses.The enantiomeric compositions of samples were determined by chirasilval capillary column gas chromatography,and the relative yields of radiolytic products (H2,CO2 and NH3) were measured by packed column gas chromatography.The obtained data showed the peak area ratios D/L of DL-leucine after different absorbed doses of irradiation are all the same as that of samples with no irradiation,within the limit of error.So are the ratios for the separately irradiated D-and L-leuicne.This suggests that no asymmetric decomposition was found.The relative yields D/L of radiolytic products (H2,CO2 and NH3) arevery close to 1.00,indicating that the D-leucine cleavage rate was the same with that of the L-leucine.From the view of dissipative structure,an explanation for the result was presented.
1993, 4(4): 367-368
Abstract:
The title compounds (Me2SiSiMe2) (η-RC5H3)Fe(CO)(μ-CO) 2(R:H(1a),Me(1b)) were prepared by heating a solution of RC5H4 (Me2SiSiMe2) C5H4R and Fe(CO)5 in xylene atreflux. (1a) and (1b) can convert into their isomers Me2Si (η-RC3H3) Fe(CO)2 2(R:H(2a),Me(2b)) under the reaction conditions.The crystal and molecular structures of (1a), (2a) and (2b) were determined by X-ray diffraction.
The title compounds (Me2SiSiMe2) (η-RC5H3)Fe(CO)(μ-CO) 2(R:H(1a),Me(1b)) were prepared by heating a solution of RC5H4 (Me2SiSiMe2) C5H4R and Fe(CO)5 in xylene atreflux. (1a) and (1b) can convert into their isomers Me2Si (η-RC3H3) Fe(CO)2 2(R:H(2a),Me(2b)) under the reaction conditions.The crystal and molecular structures of (1a), (2a) and (2b) were determined by X-ray diffraction.
1993, 4(4): 369-370
Abstract:
It has first been reported that Tb (Ⅲ) is oxidated by K2S2O8 in the heteropolytungstophosphate complex.The complex ion, [Tb(Ⅳ)(PW11O39)2]10-, is stable in aqueous solutiononly for hours,being graduately reduced to[Tb(Ⅲ)(PW11O39)2]11-.It is red-brown,with absorption band at about 420 nm.
It has first been reported that Tb (Ⅲ) is oxidated by K2S2O8 in the heteropolytungstophosphate complex.The complex ion, [Tb(Ⅳ)(PW11O39)2]10-, is stable in aqueous solutiononly for hours,being graduately reduced to[Tb(Ⅲ)(PW11O39)2]11-.It is red-brown,with absorption band at about 420 nm.
1993, 4(4): 371-372
Abstract:
both theoretical and experimental findings of the photoresponse for water spliting of the pyrolytically prepared thin film iron oxide electrodes are given.Further,the spray time and the corresponding thickness of the Fe2O3 thin film were optimized to have maximum photoresponse.The effect of iodine doping on photoresponse of iron oxide was investigated.
both theoretical and experimental findings of the photoresponse for water spliting of the pyrolytically prepared thin film iron oxide electrodes are given.Further,the spray time and the corresponding thickness of the Fe2O3 thin film were optimized to have maximum photoresponse.The effect of iodine doping on photoresponse of iron oxide was investigated.
1993, 4(4): 373-376
Abstract:
Petroleum carboxylate that may be suitable for tertiary oil recovery have been produced inexpensively from the fractions of Daqing crude oil by a two step process.The feed stock was first oxidized in the vapor phase,followed by reaction of the oxidized products with sodium hydroxide.Dilute solutions of sodium carboxylates were produced and show ultralow (10-2mN/m) interfacial tensions (IFTs) against a variety of hydrocarbons with a wide range of ACN (Alkane Carbon Number).Infrared spectroscopy was used to identify the functional groups in the oxidized and the saponified products.
Petroleum carboxylate that may be suitable for tertiary oil recovery have been produced inexpensively from the fractions of Daqing crude oil by a two step process.The feed stock was first oxidized in the vapor phase,followed by reaction of the oxidized products with sodium hydroxide.Dilute solutions of sodium carboxylates were produced and show ultralow (10-2mN/m) interfacial tensions (IFTs) against a variety of hydrocarbons with a wide range of ACN (Alkane Carbon Number).Infrared spectroscopy was used to identify the functional groups in the oxidized and the saponified products.
