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1993 Volume 4 Issue 10
1993, 4(10): 847-850
Abstract:
We report here the synthesis of cyclic peptides using benzotriazolyloxy-bis (pyrrolidino)-carbonium hexafluoro-phosphate (BBC) as a coupling reagent with high yield and speed even in low concentration compared with the other usual coupling reagents.
We report here the synthesis of cyclic peptides using benzotriazolyloxy-bis (pyrrolidino)-carbonium hexafluoro-phosphate (BBC) as a coupling reagent with high yield and speed even in low concentration compared with the other usual coupling reagents.
1993, 4(10): 851-852
Abstract:
A 6-pyridinium salt (2) was obtalned from 2', 3', 5'-tri-O-acetyhnosine by use of phosphoryl chloride as the condensmg agent. The conversion of salt (2) into 6-(2-methylphenoxy)-purinenucleoside (3) denvatives under mild condition is also described.
A 6-pyridinium salt (2) was obtalned from 2', 3', 5'-tri-O-acetyhnosine by use of phosphoryl chloride as the condensmg agent. The conversion of salt (2) into 6-(2-methylphenoxy)-purinenucleoside (3) denvatives under mild condition is also described.
1993, 4(10): 853-854
Abstract:
Initiated by CP2TiCl2/Fe redox system, 2-halotetrafluoroethyl iodides readily reacted with alkynes or alkenes to give 1:1 adducts in good to excellent yields.
Initiated by CP2TiCl2/Fe redox system, 2-halotetrafluoroethyl iodides readily reacted with alkynes or alkenes to give 1:1 adducts in good to excellent yields.
1993, 4(10): 855-856
Abstract:
Synthesis of the degradation product 2 of Yingzhaosu B was accomplished and the configuration was determined.
Synthesis of the degradation product 2 of Yingzhaosu B was accomplished and the configuration was determined.
1993, 4(10): 857-858
Abstract:
Allylation of terminal epoxides (1) to give the homoallylic alcohols (2) and bishomoallylic alcohols (3) can be carried out successfully by allyl bromide and metallic zinc or tin. The effect of substituents on epoxides was studied.
Allylation of terminal epoxides (1) to give the homoallylic alcohols (2) and bishomoallylic alcohols (3) can be carried out successfully by allyl bromide and metallic zinc or tin. The effect of substituents on epoxides was studied.
1993, 4(10): 859-860
Abstract:
Deoxoqinghaosu, a more active antimalarial compound than qinghaosu, was efficiently synthesized from the readily available dihydroqinghaosu with a new reducing reagent BH3NEt3-Me3SiCl.
Deoxoqinghaosu, a more active antimalarial compound than qinghaosu, was efficiently synthesized from the readily available dihydroqinghaosu with a new reducing reagent BH3NEt3-Me3SiCl.
1993, 4(10): 861-864
Abstract:
In the absence of organic solvents, the Lewis acid catalyzed cyclocondensation reactions between 1-naphthol and benzils gave 3-aryl-3-aryl' naphtho[1, 2-b]furan-2(3H)-ones (NFs) in good yields (62%~70%) An electrophilic substitution mechanism involving formation of n-EPD/v-EPA complexes and rearrangement of aryl group was proposed.
In the absence of organic solvents, the Lewis acid catalyzed cyclocondensation reactions between 1-naphthol and benzils gave 3-aryl-3-aryl' naphtho[1, 2-b]furan-2(3H)-ones (NFs) in good yields (62%~70%) An electrophilic substitution mechanism involving formation of n-EPD/v-EPA complexes and rearrangement of aryl group was proposed.
1993, 4(10): 865-868
Abstract:
Solventless reactions between indole and 9, 10-phenanthraquinone (PQ) have been carried out in the presence/absence of zinc chloride. The 1, 2-photoadduct between indole and PQ was identified as a possible intermediate in thermoreactions. An electrophilic substitution mechanism involving formation of n-EPD/v-EPA complex was proposed.
Solventless reactions between indole and 9, 10-phenanthraquinone (PQ) have been carried out in the presence/absence of zinc chloride. The 1, 2-photoadduct between indole and PQ was identified as a possible intermediate in thermoreactions. An electrophilic substitution mechanism involving formation of n-EPD/v-EPA complex was proposed.
1993, 4(10): 869-870
Abstract:
Allyldialkyltelluronium bromides were treated with aromatic amines in 1, 2-dichloroethane, readily giving allyl aryl amines in excellent yields. This method provides a convenient one-pot reaction for the synthesis of allylic amines.
Allyldialkyltelluronium bromides were treated with aromatic amines in 1, 2-dichloroethane, readily giving allyl aryl amines in excellent yields. This method provides a convenient one-pot reaction for the synthesis of allylic amines.
1993, 4(10): 871-872
Abstract:
The seleno substituted aromatic compounds were prepared via the Diels-Alder reaction of seleno substituted 3-sulfolenes with dimethyl acetylenedicarboxylate followed by DDQ dehydrogenation.
The seleno substituted aromatic compounds were prepared via the Diels-Alder reaction of seleno substituted 3-sulfolenes with dimethyl acetylenedicarboxylate followed by DDQ dehydrogenation.
1993, 4(10): 873-876
Abstract:
Surface species resulting from the decomposition of methanol on Na-、K-、Rb-、Cs-、BCs-、KCs- and KBCs-X zeolite at 420℃, and the relationship between surface species and the side chain alkylation selectivity from toluene with methanol have been studied by infrared and gas chromatographic methods.
Surface species resulting from the decomposition of methanol on Na-、K-、Rb-、Cs-、BCs-、KCs- and KBCs-X zeolite at 420℃, and the relationship between surface species and the side chain alkylation selectivity from toluene with methanol have been studied by infrared and gas chromatographic methods.
1993, 4(10): 877-878
Abstract:
3-Acetyltropolone (1) reacted with 2-hydroxybenzaldehyde (2a), 2-hydroxy-5-methylbenzaldehyde (2b), 5-chloro-2-hydroxybenzaldehyde (2c) and 2-hydroxy-l-naphthaldehyde in presence of ethylformate and perchlor ic acid to give the corresponding pyranylium tropolone perchlorate.
3-Acetyltropolone (1) reacted with 2-hydroxybenzaldehyde (2a), 2-hydroxy-5-methylbenzaldehyde (2b), 5-chloro-2-hydroxybenzaldehyde (2c) and 2-hydroxy-l-naphthaldehyde in presence of ethylformate and perchlor ic acid to give the corresponding pyranylium tropolone perchlorate.
1993, 4(10): 879-882
Abstract:
The average aggregate number (N) of electrostatically stabilized aggregate (ESAg) composed of oppositely-charged long-chain molecules, i. e., sodium ω-[α-(nathphyl) ethoxyl]undecanoate (FP-) and cetyltrimethyl ammonium chloride (CTAC), in aqueous solution at 25℃ has been measured to be 11 to 16 in the CTAC-concentration range of 11×10-5 M to 30×10-5 M at a fixed FP- concentration of 1.0×10-5 M by the photon counting method.
The average aggregate number (N) of electrostatically stabilized aggregate (ESAg) composed of oppositely-charged long-chain molecules, i. e., sodium ω-[α-(nathphyl) ethoxyl]undecanoate (FP-) and cetyltrimethyl ammonium chloride (CTAC), in aqueous solution at 25℃ has been measured to be 11 to 16 in the CTAC-concentration range of 11×10-5 M to 30×10-5 M at a fixed FP- concentration of 1.0×10-5 M by the photon counting method.
1993, 4(10): 883-884
Abstract:
A few factors affecting plasma oxidation desulfurization of ethylthioether were investigated. Under the typical conditions, the conversion and degree of desulfurization of ethyl-thioether can be achieved up to 88% and 79% respectively.
A few factors affecting plasma oxidation desulfurization of ethylthioether were investigated. Under the typical conditions, the conversion and degree of desulfurization of ethyl-thioether can be achieved up to 88% and 79% respectively.
1993, 4(10): 885-886
Abstract:
Two new coumarins, 4'-hydroxycolumbianetin named angelidiol (A) and 6-[1 (R), 2 (S)-3-trihydroxy-3-methylbutyl]-7-methoxycoumarin named angelitriol (B), were isolated from the EtOAc-soluble fraction of the 80% EtOH extract and structurally eluciated on the basis of spectral analyses.
Two new coumarins, 4'-hydroxycolumbianetin named angelidiol (A) and 6-[1 (R), 2 (S)-3-trihydroxy-3-methylbutyl]-7-methoxycoumarin named angelitriol (B), were isolated from the EtOAc-soluble fraction of the 80% EtOH extract and structurally eluciated on the basis of spectral analyses.
1993, 4(10): 887-890
Abstract:
From the methylene chloride extract of the leaves and stems of Taxus cuspidata Sieb et Zucc twelve taxane diterpenoids have been afforded. The structures of two novel taxane diterpenes, named 10-deacetyltaxinine B (1) and taxacustin (2) were characterized by spectroscopic techniques and X-ray diffraction analysis.
From the methylene chloride extract of the leaves and stems of Taxus cuspidata Sieb et Zucc twelve taxane diterpenoids have been afforded. The structures of two novel taxane diterpenes, named 10-deacetyltaxinine B (1) and taxacustin (2) were characterized by spectroscopic techniques and X-ray diffraction analysis.
1993, 4(10): 891-892
Abstract:
Two new cinnamamide derivatives designated as cimicifugamide (1) and isocimicifu-gamide (2), have been isolated from the rhizomes of Cimicifuga dahurica (Turcz. ) Maxim.. Theirs tructures were established based on spectral evidence as N-(3'-methoxy-4'-hydroxyphenethyl)-4-0-β-D-galactopyrano syl-ferulamide (E) and N-(3'-methoxy-4'-hydroxyphenetnyl)-4-0-β-D-galactopyranosyl-isoferulamide (Z) respectively.
Two new cinnamamide derivatives designated as cimicifugamide (1) and isocimicifu-gamide (2), have been isolated from the rhizomes of Cimicifuga dahurica (Turcz. ) Maxim.. Theirs tructures were established based on spectral evidence as N-(3'-methoxy-4'-hydroxyphenethyl)-4-0-β-D-galactopyrano syl-ferulamide (E) and N-(3'-methoxy-4'-hydroxyphenetnyl)-4-0-β-D-galactopyranosyl-isoferulamide (Z) respectively.
1993, 4(10): 893-894
Abstract:
A new sesquiterpene with an eudesmane skeleton, named Chrysantherol was isolated from the flowers of Chrysanthemum indicum. Its structure was elucidated as 1 mainly by the analysis of spectral data.
A new sesquiterpene with an eudesmane skeleton, named Chrysantherol was isolated from the flowers of Chrysanthemum indicum. Its structure was elucidated as 1 mainly by the analysis of spectral data.
1993, 4(10): 895-898
Abstract:
Phytochemical investigation of the roots of Ligularia nelumbifolia afforded three new sinapyl alcohol derivatives together with two other novel constituents. Their structures were elucidated by high field 1D and 2D NMR techniques and chemical transformations.
Phytochemical investigation of the roots of Ligularia nelumbifolia afforded three new sinapyl alcohol derivatives together with two other novel constituents. Their structures were elucidated by high field 1D and 2D NMR techniques and chemical transformations.
1993, 4(10): 899-902
Abstract:
The detection of the microwave-discharged species of methyl iodide by HeI photoelectron spectroscopy (UPS) is reported for the first time. The UPS spectra of I2 and HI molecules clearly appeared in the spectrum of microwave-discharged species of methyl iodide, The mechanism of the change of methyl iodide under microwave discharge was proposed, The result provides the basis for understanding depletion of the ozone shell of the atomsphere by halogenated methane.
The detection of the microwave-discharged species of methyl iodide by HeI photoelectron spectroscopy (UPS) is reported for the first time. The UPS spectra of I2 and HI molecules clearly appeared in the spectrum of microwave-discharged species of methyl iodide, The mechanism of the change of methyl iodide under microwave discharge was proposed, The result provides the basis for understanding depletion of the ozone shell of the atomsphere by halogenated methane.
1993, 4(10): 903-906
Abstract:
The fully anisotropic molecular overall tumbling model with methyl conformation jumps internal rotation among three equivalent sites is proposed, the overall tumbling rotation rates and the methyl internal rotation rates of ponicidin are computed with this model from 13C relaxation parameters.
The fully anisotropic molecular overall tumbling model with methyl conformation jumps internal rotation among three equivalent sites is proposed, the overall tumbling rotation rates and the methyl internal rotation rates of ponicidin are computed with this model from 13C relaxation parameters.
1993, 4(10): 907-908
Abstract:
The molecular recognition of the α, β-CD and 6A, 6C(D)-o, o'-(4, 4'-diphenyloxide-disulfonyl)-β-CD to naphthalene derivatives was studied by fluorescence and circular dichroism spectra. The formation constants of the inclusion complexes were estimated based on the variation of fluorescent intensity and the modified Benesi-Hildebrand equations.
The molecular recognition of the α, β-CD and 6A, 6C(D)-o, o'-(4, 4'-diphenyloxide-disulfonyl)-β-CD to naphthalene derivatives was studied by fluorescence and circular dichroism spectra. The formation constants of the inclusion complexes were estimated based on the variation of fluorescent intensity and the modified Benesi-Hildebrand equations.
1993, 4(10): 909-912
Abstract:
In this paper, we report the study of surface-enhanced Raman Scattering of C60 films on roughed Ag, Cu and glass surface. The experiment results indicate that the C60 films on Ag substrate possess large enhance effect. An explanation of the enhancement with roughed glass surface is proposed based on waveguide Raman Scattering.
In this paper, we report the study of surface-enhanced Raman Scattering of C60 films on roughed Ag, Cu and glass surface. The experiment results indicate that the C60 films on Ag substrate possess large enhance effect. An explanation of the enhancement with roughed glass surface is proposed based on waveguide Raman Scattering.
1993, 4(10): 913-916
Abstract:
Organic acids in 3 kinds of soy sauces were analyzed by HRLC. Column:C18 μ Bondapak (10μm, 3.9mm i. d. * 30cm;mobile phase:0.5% (NH4)2HPO4 (pH=2.9);flow rate:1.0 ml/m. PT-C18 cartridge was used for the sample preparation. Recoveries of organic acids are between 96-111%.
Organic acids in 3 kinds of soy sauces were analyzed by HRLC. Column:C18 μ Bondapak (10μm, 3.9mm i. d. * 30cm;mobile phase:0.5% (NH4)2HPO4 (pH=2.9);flow rate:1.0 ml/m. PT-C18 cartridge was used for the sample preparation. Recoveries of organic acids are between 96-111%.
1993, 4(10): 917-920
Abstract:
In this paper the analytical performance of the low-powered Ar microwave plasma torch atomic emission spectrometry (MPT-AES) was studied. The experimental results indicate that the analytical performance of low-powered ArMPT-AES is satisfactory.
In this paper the analytical performance of the low-powered Ar microwave plasma torch atomic emission spectrometry (MPT-AES) was studied. The experimental results indicate that the analytical performance of low-powered ArMPT-AES is satisfactory.
1993, 4(10): 921-924
Abstract:
A research on the application of a TG-DTA (thermal gravimetry differential thermal analysis) to the quick determination of moisture, organic volatile fixed carbon, ash and caloric value for coal is described.
A research on the application of a TG-DTA (thermal gravimetry differential thermal analysis) to the quick determination of moisture, organic volatile fixed carbon, ash and caloric value for coal is described.
1993, 4(10): 925-928
Abstract:
In the 0.3mol/L NH4Cl supporting electrolyte, salicyl-fluorone exhibits a sensitive adsorptive wave by using linear scanning voltammetry with Ep1=-0.70V and a diffusion wave with Ep2=-0.68V (vs. SCE) at pH 2.5. On the surface of HMDE, the adsorption of salieyl-fluorone obeys Frumkin adsorption isotherm. The adsorption coefficient (B), and attractive factor (v) and the amount of saturated adsorption (Γs) have been determined.
In the 0.3mol/L NH4Cl supporting electrolyte, salicyl-fluorone exhibits a sensitive adsorptive wave by using linear scanning voltammetry with Ep1=-0.70V and a diffusion wave with Ep2=-0.68V (vs. SCE) at pH 2.5. On the surface of HMDE, the adsorption of salieyl-fluorone obeys Frumkin adsorption isotherm. The adsorption coefficient (B), and attractive factor (v) and the amount of saturated adsorption (Γs) have been determined.
1993, 4(10): 929-930
Abstract:
Two vanadium complexes of schiff base with rich phenolate oxygen, o-N-salicylideneamino-methylphenol, had been synthesized and characterized. One is a V(Ⅳ) complex with an interaction via vanadyl oxygen and the other is a novel dinuclear V(V, V) complex with an oxo bridge. The conversion between the two complexes had been discussed.
Two vanadium complexes of schiff base with rich phenolate oxygen, o-N-salicylideneamino-methylphenol, had been synthesized and characterized. One is a V(Ⅳ) complex with an interaction via vanadyl oxygen and the other is a novel dinuclear V(V, V) complex with an oxo bridge. The conversion between the two complexes had been discussed.
1993, 4(10): 931-932
Abstract:
A new dimolybdenum (V) complex[(C6H4Cl)2C(Ph)]2[Mo2(μ-Cl)3Cl4O2] [Mo2(μ-Cl)2Cl4O2(μ-OCOPh)]has been obtained in the reaction of PhCl with benzoyl peroxide (PhCO2)2 and MoCl5. Its crystal structure has been determined by X-ray diffraction methods. Spectroscopic characterization of the compound and ASED-MO calculation of the trityl cation are reported.
A new dimolybdenum (V) complex[(C6H4Cl)2C(Ph)]2[Mo2(μ-Cl)3Cl4O2] [Mo2(μ-Cl)2Cl4O2(μ-OCOPh)]has been obtained in the reaction of PhCl with benzoyl peroxide (PhCO2)2 and MoCl5. Its crystal structure has been determined by X-ray diffraction methods. Spectroscopic characterization of the compound and ASED-MO calculation of the trityl cation are reported.
1993, 4(10): 933-934
Abstract:
This paper reports the determination of stability constants for complexes of Cd (Ⅱ) with Gly, Ala, Val, Asp, Gly-Asp, Asp Gly, Gly-Gly and Gly-Gly-Gly using both micro-pH-metric titrations and the application of convolution-deconvolution cyclic voltammetry at 25℃ and I=0.10 mol·dm-3 (KNO3). Stability constants were calculated from pH-metric data using the SUPERQUAD computer program and cyclic voltammograms were collected, stored and manipulated using the EG and G CONDECON 300 software. A considerably larger ligand:metal ratio (e, g. 50:1) was possible using voltammetry. Evaluation of results from the two techniques suggests that stability constants for the species[CdL2]and[CdL3]are reliable when calculated fromvoltammetry while those for[CdL]are more reliable when determined by pH-metric titration.
This paper reports the determination of stability constants for complexes of Cd (Ⅱ) with Gly, Ala, Val, Asp, Gly-Asp, Asp Gly, Gly-Gly and Gly-Gly-Gly using both micro-pH-metric titrations and the application of convolution-deconvolution cyclic voltammetry at 25℃ and I=0.10 mol·dm-3 (KNO3). Stability constants were calculated from pH-metric data using the SUPERQUAD computer program and cyclic voltammograms were collected, stored and manipulated using the EG and G CONDECON 300 software. A considerably larger ligand:metal ratio (e, g. 50:1) was possible using voltammetry. Evaluation of results from the two techniques suggests that stability constants for the species[CdL2]and[CdL3]are reliable when calculated fromvoltammetry while those for[CdL]are more reliable when determined by pH-metric titration.
1993, 4(10): 935-936
Abstract:
The salt titration of goethite (α-FeOOH) aqueous suspension had been carried out with the addition of solid NaCl at several different starting pH values and the point of zero charge (pzc) was estimated. Then the electrophoretic mobilities of positively charged αFeOOH particles dispersed in NaCl solution were measured as a function of pH to obtain the isoelectric point (iep). The two parameters were compared.
The salt titration of goethite (α-FeOOH) aqueous suspension had been carried out with the addition of solid NaCl at several different starting pH values and the point of zero charge (pzc) was estimated. Then the electrophoretic mobilities of positively charged αFeOOH particles dispersed in NaCl solution were measured as a function of pH to obtain the isoelectric point (iep). The two parameters were compared.
1993, 4(10): 937-938
Abstract:
The structure of Na2H2[H2V2W18O62]12H2O has been determined by x-ray analysis. The crystals are trigonal, space group R3m, with cell parameters a=37.613 (11), c=12.972 (7) A, V=15901 (13) A3, and Z=9. The structure model was refined by full-matrix least square to R=0.065 for 1702 reflections with F>4σ (F). The existence of the[H2V2W18O62]4- heteropolyanion in the crystals has been confirmed. It is composed of two VO4 tetrahedra and eighteen WO6 octahedra linked to give the Dawson-type structure.
The structure of Na2H2[H2V2W18O62]12H2O has been determined by x-ray analysis. The crystals are trigonal, space group R3m, with cell parameters a=37.613 (11), c=12.972 (7) A, V=15901 (13) A3, and Z=9. The structure model was refined by full-matrix least square to R=0.065 for 1702 reflections with F>4σ (F). The existence of the[H2V2W18O62]4- heteropolyanion in the crystals has been confirmed. It is composed of two VO4 tetrahedra and eighteen WO6 octahedra linked to give the Dawson-type structure.
1993, 4(10): 939-940
Abstract:
The surface pressure-Area isotherms of Reversed Duckweed amphiphilic polymer were examined in view of their chemical structure and twodimentional properties of polymer monolayer were studied.
The surface pressure-Area isotherms of Reversed Duckweed amphiphilic polymer were examined in view of their chemical structure and twodimentional properties of polymer monolayer were studied.
