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1991 Volume 2 Issue 3
1991, 2(3): 189-190
Abstract:
The configuration of the hydroxy acid 2, a product from base-catalyzed autoxidation of 3α, 5-cyclo-5α-cholestane-6-one, was established on the basis of NMR techniques and the mechanism of the formation of 2 was discussed.
The configuration of the hydroxy acid 2, a product from base-catalyzed autoxidation of 3α, 5-cyclo-5α-cholestane-6-one, was established on the basis of NMR techniques and the mechanism of the formation of 2 was discussed.
1991, 2(3): 191-192
Abstract:
When α-ketothioanilide reacts with o-phenylenediamine, there are two competing reactions. One is condensation which forms substituted quinoxaline and the other is substitution which forms substituted quinoxaline-2-thione. By controlling the reaction condition, we can obtain either quinoxaline or quinoxaline-2-thione as the main product.
When α-ketothioanilide reacts with o-phenylenediamine, there are two competing reactions. One is condensation which forms substituted quinoxaline and the other is substitution which forms substituted quinoxaline-2-thione. By controlling the reaction condition, we can obtain either quinoxaline or quinoxaline-2-thione as the main product.
1991, 2(3): 193-194
Abstract:
4, 4-Dialkyl-2-oxazolin-5-ones are prepared by one step reaction of 2-oxazolin-5-one with the magnesium methyl carbonate (MMC) and alkyIhalides. It is a novel and convenient method for synthesis of α, α-disubstitutcd α-amino acid by hydrolysis of 4, 4-dialkyl-2-oxazolin-5-ones.
4, 4-Dialkyl-2-oxazolin-5-ones are prepared by one step reaction of 2-oxazolin-5-one with the magnesium methyl carbonate (MMC) and alkyIhalides. It is a novel and convenient method for synthesis of α, α-disubstitutcd α-amino acid by hydrolysis of 4, 4-dialkyl-2-oxazolin-5-ones.
1991, 2(3): 195-196
Abstract:
The synthesis of a new type of hetero-macrocyclic polyether 2, 3-henzo-1, 4, 7, 13-tetraoxa-10-selenacyclopentadeca-2-ene is deseribed.
The synthesis of a new type of hetero-macrocyclic polyether 2, 3-henzo-1, 4, 7, 13-tetraoxa-10-selenacyclopentadeca-2-ene is deseribed.
1991, 2(3): 197-200
Abstract:
The struetural effect of the conjugative system (C) with carbonyl-imino bridges has been studied. The results show that:In the conjugated system (C), there is no electronic absorption peak attributable to the whole system, but there are three π-π* bands each of which displays chacactecistics of its own independently. These indicate that the two bridges-carbonyl-and-imino-can block the tlansmlssion of the conjngative polarization of the whole system, so as to form three segments, this is verified by means of chemical synthesis and degradation.
The struetural effect of the conjugative system (C) with carbonyl-imino bridges has been studied. The results show that:In the conjugated system (C), there is no electronic absorption peak attributable to the whole system, but there are three π-π* bands each of which displays chacactecistics of its own independently. These indicate that the two bridges-carbonyl-and-imino-can block the tlansmlssion of the conjngative polarization of the whole system, so as to form three segments, this is verified by means of chemical synthesis and degradation.
1991, 2(3): 201-204
Abstract:
The asymmetric alkylations of chiral transition metal complexes derived from (+)-camphor and 2-aminomethyl-6-methylpyridine were examined under mild conditions. The formation of the complexes 2 is conductive to the enhancement of diastereoselectivity in the alkylations at room temperature.
The asymmetric alkylations of chiral transition metal complexes derived from (+)-camphor and 2-aminomethyl-6-methylpyridine were examined under mild conditions. The formation of the complexes 2 is conductive to the enhancement of diastereoselectivity in the alkylations at room temperature.
1991, 2(3): 205-208
Abstract:
A novel β-cyclodextrin (β-CD) derivative bearing diethanolamine moiety was synthesized by a convenient method with 63% yield, and the new host compound was characterized by 13C-NMR, FT-IR spectra etc.
A novel β-cyclodextrin (β-CD) derivative bearing diethanolamine moiety was synthesized by a convenient method with 63% yield, and the new host compound was characterized by 13C-NMR, FT-IR spectra etc.
1991, 2(3): 209-212
Abstract:
Alkylated propargyl bromides react with phosphiaes in acidic tetrahydrofuran solution to give propargylic phosphonium salts in good yield.
Alkylated propargyl bromides react with phosphiaes in acidic tetrahydrofuran solution to give propargylic phosphonium salts in good yield.
1991, 2(3): 213-216
Abstract:
Ethyl N-cyanomethytbenzenecarboximidate reacted with aliphatic aldehydes under the solid-liquid PTC condition to gire α-ethoxyphenylmethylene-aminoacrylonitrile derivatives and oxazoline derivatives. It is a convenient and new method for synthesis of β, β'-dihyroxy-α-amino acids by hydrolysis of the oxazoline derivatives.
Ethyl N-cyanomethytbenzenecarboximidate reacted with aliphatic aldehydes under the solid-liquid PTC condition to gire α-ethoxyphenylmethylene-aminoacrylonitrile derivatives and oxazoline derivatives. It is a convenient and new method for synthesis of β, β'-dihyroxy-α-amino acids by hydrolysis of the oxazoline derivatives.
1991, 2(3): 217-220
Abstract:
The 1, 3-dipolar cycloaddition reaction of 2-trifluoromethyl-oxazolone and the activated carbon-carbon multiple bond was studied and gave a convenient way to synthesize 2-trifluoromethylpyrrole derivatives.
The 1, 3-dipolar cycloaddition reaction of 2-trifluoromethyl-oxazolone and the activated carbon-carbon multiple bond was studied and gave a convenient way to synthesize 2-trifluoromethylpyrrole derivatives.
1991, 2(3): 221-222
Abstract:
Two new cornpounds, saponin I and saponin Ⅱ, were isolated from Gynostemma longipes C. Y. Wu. The struetures have been characterized on the basis of chemical and spectroscopic evidence.
Two new cornpounds, saponin I and saponin Ⅱ, were isolated from Gynostemma longipes C. Y. Wu. The struetures have been characterized on the basis of chemical and spectroscopic evidence.
1991, 2(3): 223-226
Abstract:
Three new diterpenoids, named esquirolin B (1), C (2), D (3) respectively, and two known cemocunds-eariocal (4) and taraxerol were isolated from Coleus esquirolii (Levl). The structure elucidation was achieved by spectroscopic means.
Three new diterpenoids, named esquirolin B (1), C (2), D (3) respectively, and two known cemocunds-eariocal (4) and taraxerol were isolated from Coleus esquirolii (Levl). The structure elucidation was achieved by spectroscopic means.
1991, 2(3): 227-230
Abstract:
From rhizomes of Curculigo orchioideg (Xian Mao) six new cyclo-artane glycosides named curculigosaponin A~F were isolated. The new triterpenoidal sapogenin named curculigenin A, whlch is common to curculigo-saponin A~F, was formulated as 3β, 11α, 16β-trihydroxycycloartane-24-one by HR-MS and 2D-NMR technical analysis. On the basis of chemical evidence and spectral data, the structures of these saponins were elucidated.
From rhizomes of Curculigo orchioideg (Xian Mao) six new cyclo-artane glycosides named curculigosaponin A~F were isolated. The new triterpenoidal sapogenin named curculigenin A, whlch is common to curculigo-saponin A~F, was formulated as 3β, 11α, 16β-trihydroxycycloartane-24-one by HR-MS and 2D-NMR technical analysis. On the basis of chemical evidence and spectral data, the structures of these saponins were elucidated.
1991, 2(3): 231-232
Abstract:
A new artifact bisbenzylisoquinoline, 2, 2'-N, N-dichloromethyltetrandrine (1), has been ob-tained from the root of Stephania tetrandra and its structure has been advanced on the basis of spectroscopic and chemical evidence.
A new artifact bisbenzylisoquinoline, 2, 2'-N, N-dichloromethyltetrandrine (1), has been ob-tained from the root of Stephania tetrandra and its structure has been advanced on the basis of spectroscopic and chemical evidence.
1991, 2(3): 233-236
Abstract:
The UV absorption spectra of α-naphthol, α-naphthylamine, 2, 7-dihydroxy naphthalene, 2, 4-dimethoxy ben-zaldehyde and methyl salicylate, overlap severely;therefore it is impossible to determine them in mixtures by traditional spectrophotometric methods. In this paper, the partial least-squares (PLS) regression is applied to the simultaneous determination of these compounds in mixtures by UV spectrophtometry without any pretreatment of the samples. Ten synthetic mixture samples are analyzed by the proposed method. The mean recoveries are 99.4%, 99.6%, 100.2%, 99.3% and 99.1%, and the relative standard deviations (RSD) are 1.87%, 1.98%, 1.94%, 0.960% and 0.672%, respectively.
The UV absorption spectra of α-naphthol, α-naphthylamine, 2, 7-dihydroxy naphthalene, 2, 4-dimethoxy ben-zaldehyde and methyl salicylate, overlap severely;therefore it is impossible to determine them in mixtures by traditional spectrophotometric methods. In this paper, the partial least-squares (PLS) regression is applied to the simultaneous determination of these compounds in mixtures by UV spectrophtometry without any pretreatment of the samples. Ten synthetic mixture samples are analyzed by the proposed method. The mean recoveries are 99.4%, 99.6%, 100.2%, 99.3% and 99.1%, and the relative standard deviations (RSD) are 1.87%, 1.98%, 1.94%, 0.960% and 0.672%, respectively.
1991, 2(3): 237-238
Abstract:
Three hypotheses of the electrochemical reaction mechanism of the Dy (Ⅲ)-ALC complex were put forward, based on the experimental results. Then it has been confirmed by simplex-deviation-pattern reoognition that the pola-rographic wave of the Dy (Ⅲ)-ALC complex was an adsorptive-complex wave.
Three hypotheses of the electrochemical reaction mechanism of the Dy (Ⅲ)-ALC complex were put forward, based on the experimental results. Then it has been confirmed by simplex-deviation-pattern reoognition that the pola-rographic wave of the Dy (Ⅲ)-ALC complex was an adsorptive-complex wave.
1991, 2(3): 239-242
Abstract:
Thionine-eontaining chemically modified eleetrode (CME) were constructed with glassy carbon substrate employing various procedures, with which electrocatalytic reduction of hemoglobin (Hb) was carried out and characterized under static and flow conditions. Linear response range over 2 orders of magnitude and detection limit of subpieomole were achieved at the CME in FIA.
Thionine-eontaining chemically modified eleetrode (CME) were constructed with glassy carbon substrate employing various procedures, with which electrocatalytic reduction of hemoglobin (Hb) was carried out and characterized under static and flow conditions. Linear response range over 2 orders of magnitude and detection limit of subpieomole were achieved at the CME in FIA.
1991, 2(3): 243-244
Abstract:
Enantiomers of α-substituted-(2-pyridyl)-methylarfdnes were separated on SC-7 gas chromatograph with a 20m×0.25mm Chirasil-Val capIlary column, Carrier gas was nitro-gen or hydrogen. The resolution factors (ri.s) were 1.02 to 1.06. Enantiomers of pyridyl anines were separated to and near to base line.
Enantiomers of α-substituted-(2-pyridyl)-methylarfdnes were separated on SC-7 gas chromatograph with a 20m×0.25mm Chirasil-Val capIlary column, Carrier gas was nitro-gen or hydrogen. The resolution factors (ri.s) were 1.02 to 1.06. Enantiomers of pyridyl anines were separated to and near to base line.
1991, 2(3): 245-248
Abstract:
Correlation between the absolute configuration and the CD spectra of organic peroxides was studied by ab initio method with a mo-del moleeule CH3-O-O-CH3. For P form when 0° ≤θ (twist angle of C-O-O-C) <90°, there is positive Cotton effect;when 90°< θ ≤180°, there is negative Cotton effect;the curve is bisignate at θ=90°.
Correlation between the absolute configuration and the CD spectra of organic peroxides was studied by ab initio method with a mo-del moleeule CH3-O-O-CH3. For P form when 0° ≤θ (twist angle of C-O-O-C) <90°, there is positive Cotton effect;when 90°< θ ≤180°, there is negative Cotton effect;the curve is bisignate at θ=90°.
1991, 2(3): 249-250
Abstract:
Fe3+ substituted ZSM-5 zeolite was studied using EPR and 27Al, 29Si MAS-NMR spectroscopy. The results showed that the synthe-sized sample has the typical ZSM-5 structure with Fe3+ ionsincorporated in tetrahedric sites in the zeolite framework and there are some para-magnetic centers in the samples.
Fe3+ substituted ZSM-5 zeolite was studied using EPR and 27Al, 29Si MAS-NMR spectroscopy. The results showed that the synthe-sized sample has the typical ZSM-5 structure with Fe3+ ionsincorporated in tetrahedric sites in the zeolite framework and there are some para-magnetic centers in the samples.
1991, 2(3): 251-252
Abstract:
The reduction of H+ on Ti electrodes which were treated by implanting nickel ions and thermodiffusing in vacuum has been studied. The calytic activity of the afore-mentioned electroes for H+ reduction is much higher than that of the untreated Ti electrodes.
The reduction of H+ on Ti electrodes which were treated by implanting nickel ions and thermodiffusing in vacuum has been studied. The calytic activity of the afore-mentioned electroes for H+ reduction is much higher than that of the untreated Ti electrodes.
1991, 2(3): 253-254
Abstract:
The chemisorption intensities of NH3 and CO on aluminum clusters Aln (n=l-13) have been theoretically predicted by using CNDO/2 method and properly selecting the clusters'geometries. The results show that the chemisorptions of NH3 and GO on Al2, Al6 and Al12 are magically stable and thus are in good agreement with the experimental results. In addition, an electronic structure analysis is made to expound the nature of such a size effect.
The chemisorption intensities of NH3 and CO on aluminum clusters Aln (n=l-13) have been theoretically predicted by using CNDO/2 method and properly selecting the clusters'geometries. The results show that the chemisorptions of NH3 and GO on Al2, Al6 and Al12 are magically stable and thus are in good agreement with the experimental results. In addition, an electronic structure analysis is made to expound the nature of such a size effect.
1991, 2(3): 255-258
Abstract:
The dispersion behavior of MoO3 on ZSM-11 and effect of dispersed MoO3 on the framework structure of ZSM-11 have been studjed using X-ray diffraction and infrared spectroscopy.
The dispersion behavior of MoO3 on ZSM-11 and effect of dispersed MoO3 on the framework structure of ZSM-11 have been studjed using X-ray diffraction and infrared spectroscopy.
1991, 2(3): 259-260
Abstract:
Two new water-soluble binuclear copper (Ⅱ) chelates derived from the condensation of 2, 6-diformyl-4-methylphenol with glycylglycine were characterized with spectral. magnetic and electrochemical techniques.
Two new water-soluble binuclear copper (Ⅱ) chelates derived from the condensation of 2, 6-diformyl-4-methylphenol with glycylglycine were characterized with spectral. magnetic and electrochemical techniques.
1991, 2(3): 261-262
Abstract:
The electronic modification effect of various metal oxides over Pt-Al2O3 catalyst and the relationships between the polarizing force of cations (PFC) and the electrophilic character (EC) and catalytic performances (CP) of promoted Pt catalyst have been studiec by competitive hydrogenation reaction method (CHRM) and test reaction, i. e. hydrogena-tion of benzene and hydrogenolysis of cyclopentane.
The electronic modification effect of various metal oxides over Pt-Al2O3 catalyst and the relationships between the polarizing force of cations (PFC) and the electrophilic character (EC) and catalytic performances (CP) of promoted Pt catalyst have been studiec by competitive hydrogenation reaction method (CHRM) and test reaction, i. e. hydrogena-tion of benzene and hydrogenolysis of cyclopentane.
1991, 2(3): 263-266
Abstract:
Synthesis of complexes (η5-CH3C5H4) M(CO)2NO (M=Mo, I;M=W, Ⅱ) and clusters (η5-CH3C5H4) M (μ3-NH) (μ2-NO) (μ2-CO) Fe2(CO)6 (M=Mo, Ⅲ:M=W, IV), based on the reaction of (η5-C5H4) M(CO)3Cl with Na[Fe(CO)3NO] at room tem-perature, have been demonstrated, The crystal structures of Ⅱ and IV are also presented.
Synthesis of complexes (η5-CH3C5H4) M(CO)2NO (M=Mo, I;M=W, Ⅱ) and clusters (η5-CH3C5H4) M (μ3-NH) (μ2-NO) (μ2-CO) Fe2(CO)6 (M=Mo, Ⅲ:M=W, IV), based on the reaction of (η5-C5H4) M(CO)3Cl with Na[Fe(CO)3NO] at room tem-perature, have been demonstrated, The crystal structures of Ⅱ and IV are also presented.
