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1996 Volume 7 Issue 8
1996, 7(8): 691-692
Abstract:
Treatment of 1.4-diaryl-2.3-dirnethyl-2, 3-epoxide of butane (1) with 2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ) in trifluoroacetic acid (TFA) furnishes a new benzofuran type lignan (2). The structure of (2) was established by MS, IR, UV and NMR spectra, and X-ray crystallographic analysis.
Treatment of 1.4-diaryl-2.3-dirnethyl-2, 3-epoxide of butane (1) with 2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ) in trifluoroacetic acid (TFA) furnishes a new benzofuran type lignan (2). The structure of (2) was established by MS, IR, UV and NMR spectra, and X-ray crystallographic analysis.
1996, 7(8): 693-694
Abstract:
Synthesis of a new macromolecule with MW up to 7.6 KDA is described in the present paper. The ligation between a dendrimeric amino-PEG and unprotected peptides via a site-specific reaction is a useful trial for the preparation of synthetic vaccine and related compounds.
Synthesis of a new macromolecule with MW up to 7.6 KDA is described in the present paper. The ligation between a dendrimeric amino-PEG and unprotected peptides via a site-specific reaction is a useful trial for the preparation of synthetic vaccine and related compounds.
1996, 7(8): 695-696
Abstract:
A novel diastereoselective route to (+)-α-cyperone (1) and (-)-10-epi-α-cyperone (2) has been developed. The key step involves an asymmetric Michael addition of the corresponding chiral imine, derived from R-(+)-dihydrocarvone (3), to ethyl vinyl ketone.
A novel diastereoselective route to (+)-α-cyperone (1) and (-)-10-epi-α-cyperone (2) has been developed. The key step involves an asymmetric Michael addition of the corresponding chiral imine, derived from R-(+)-dihydrocarvone (3), to ethyl vinyl ketone.
1996, 7(8): 697-698
Abstract:
The Diels-Alder reaction of myrcene and acrolein catalyzed by modified HY zeolite which was prepared by mixing HY zeolite and anhydrous ZnCl2 under microwave irradiation was studied. High regioselectivity and good yield of para myrac aldehyde were obtained when the ratio of ZnCl2/HY (w/w) was 1:2 to 1:3.
The Diels-Alder reaction of myrcene and acrolein catalyzed by modified HY zeolite which was prepared by mixing HY zeolite and anhydrous ZnCl2 under microwave irradiation was studied. High regioselectivity and good yield of para myrac aldehyde were obtained when the ratio of ZnCl2/HY (w/w) was 1:2 to 1:3.
1996, 7(8): 699-700
Abstract:
The title compound[C16H22Br2O5] (3). was synthesized and characterized by 1H-NMR, MS and elemental analysis. Pale yellow prism crystallized from anhydrous ethanol solution was investigated by X-ray structural analysis. Crystal data:orthorhombic system, space group Pbca, Mr=454.2, a=17.664 (4) Å, b=8.625 (2) Å, c=24.269 (5) Å, z=8, Dc=1.632g/cm3, F (000) =1776. The structure was solved by direct methods and refined to final R=0.0362, Rw=0.0357 for 1029 observed reflections with F>6.0σ (F).
The title compound[C16H22Br2O5] (3). was synthesized and characterized by 1H-NMR, MS and elemental analysis. Pale yellow prism crystallized from anhydrous ethanol solution was investigated by X-ray structural analysis. Crystal data:orthorhombic system, space group Pbca, Mr=454.2, a=17.664 (4) Å, b=8.625 (2) Å, c=24.269 (5) Å, z=8, Dc=1.632g/cm3, F (000) =1776. The structure was solved by direct methods and refined to final R=0.0362, Rw=0.0357 for 1029 observed reflections with F>6.0σ (F).
1996, 7(8): 701-702
Abstract:
Three new natural compounds, 6-farnesyl-3', 4', 5, 7-tetrahydroxyflavanone (1), 3-farnesyl-2, 4, 6-trihydroxyacetophenone (2) and 4-farnesyloxy-2, 6-dihydroxyacetophenone (3) were synthesized by starting from 2, 4, 6-trihydroxyacetophenone and famesyl bromide.
Three new natural compounds, 6-farnesyl-3', 4', 5, 7-tetrahydroxyflavanone (1), 3-farnesyl-2, 4, 6-trihydroxyacetophenone (2) and 4-farnesyloxy-2, 6-dihydroxyacetophenone (3) were synthesized by starting from 2, 4, 6-trihydroxyacetophenone and famesyl bromide.
1996, 7(8): 703-705
Abstract:
a new kind of catalyst, chiral β-diketone copper complex Cu (facam) 2 was used for the first time for the asymmetric cyclopropanation of 2, 5-dimethyl-2, 4-hexadiene with alkyl diazoacetate to give the alkyl esters of chrysanthemic acids. This catalyst was prepared starting with camphor to achieve 86.7% of the products.
a new kind of catalyst, chiral β-diketone copper complex Cu (facam) 2 was used for the first time for the asymmetric cyclopropanation of 2, 5-dimethyl-2, 4-hexadiene with alkyl diazoacetate to give the alkyl esters of chrysanthemic acids. This catalyst was prepared starting with camphor to achieve 86.7% of the products.
1996, 7(8): 706-708
Abstract:
Preliminary studies on the intramolecular cyclization of amides 11 and 15 in an attempt to synthesize the natural products homoclausenamide 1 and zetaclausenamide 2 were reported.
Preliminary studies on the intramolecular cyclization of amides 11 and 15 in an attempt to synthesize the natural products homoclausenamide 1 and zetaclausenamide 2 were reported.
1996, 7(8): 709-712
Abstract:
Ultrasonically dispersed potassium (UDP) in toluene was found to be an effective deprotonating and coupling agent in the condensation of phenylacetonitrile with aldehydes;α, β-Unsaturated nitriles and their dimers 1, 6-dinitriles may be obtained by one-pot synthesis within few minutes.
Ultrasonically dispersed potassium (UDP) in toluene was found to be an effective deprotonating and coupling agent in the condensation of phenylacetonitrile with aldehydes;α, β-Unsaturated nitriles and their dimers 1, 6-dinitriles may be obtained by one-pot synthesis within few minutes.
1996, 7(8): 711-712
Abstract:
Ligustiphenol (Ⅰ), a new sesquiterpenoid with bisabolane skeleton, has been isolated from the alcohol extract of roots of Ligusticum sinence Oliv, and its strcuture including absolute configuration established on the basis of spectral and chemical evidences.
Ligustiphenol (Ⅰ), a new sesquiterpenoid with bisabolane skeleton, has been isolated from the alcohol extract of roots of Ligusticum sinence Oliv, and its strcuture including absolute configuration established on the basis of spectral and chemical evidences.
1996, 7(8): 713-716
Abstract:
Gallium-mediated Reformatsky-type reactions gave ethyl esters of β-hydroxy acids, and ethyl esters of-α-vinyl-β-hydroxy acids in excellent yields and very high regioselectivity.
Gallium-mediated Reformatsky-type reactions gave ethyl esters of β-hydroxy acids, and ethyl esters of-α-vinyl-β-hydroxy acids in excellent yields and very high regioselectivity.
1996, 7(8): 717-720
Abstract:
Trichloromethanesulfonyl bromide can be used as a telogen with tetrafluoroethylene and chlorotrifluoroethylene as monomers to give telomerized products CCl3 (CF2CF2) nBr and CCl3 (CF2CFCl) nBr without an initiator.
Trichloromethanesulfonyl bromide can be used as a telogen with tetrafluoroethylene and chlorotrifluoroethylene as monomers to give telomerized products CCl3 (CF2CF2) nBr and CCl3 (CF2CFCl) nBr without an initiator.
1996, 7(8): 723-724
Abstract:
A new norditerpenoid alkaloid, hemsleyadine, was isolated from the roots of Aconitum hemsleyanum var. circinatum. Structure of hemsleyadine was assigned as 1 by comparison of its 13C NMR data with known compounds.
A new norditerpenoid alkaloid, hemsleyadine, was isolated from the roots of Aconitum hemsleyanum var. circinatum. Structure of hemsleyadine was assigned as 1 by comparison of its 13C NMR data with known compounds.
1996, 7(8): 725-728
Abstract:
Two new norditerpenoid alkaloids leucostines A (1) and B (2) have been isolated from the root of Aconitum leucostomum. Their structures were elucidated on the basis of spectral data and chemical evidence.
Two new norditerpenoid alkaloids leucostines A (1) and B (2) have been isolated from the root of Aconitum leucostomum. Their structures were elucidated on the basis of spectral data and chemical evidence.
1996, 7(8): 729-732
Abstract:
The electrochemical redox reaction of hemoglobin on bare silver electrode using cetyl pyridinium chloride as promoter is described. The electrode reaction exhibits such a good stability that the peak currents change less than 8.5% (oxidation) and 10.2% (reduction) in continuing scan of 30 min in a solution containing 1×10-7 mol/L hemoglobin. The rate constant Ks is 0.0865s-1 with a single electron transfer. Moreover, both the oxidation and the reduction currents are linearly related with the hemoglobin concentration in the range of 1×10-8~5×10-7 mol/L. So, it can be used as an analytical method for determining hemoglobin.
The electrochemical redox reaction of hemoglobin on bare silver electrode using cetyl pyridinium chloride as promoter is described. The electrode reaction exhibits such a good stability that the peak currents change less than 8.5% (oxidation) and 10.2% (reduction) in continuing scan of 30 min in a solution containing 1×10-7 mol/L hemoglobin. The rate constant Ks is 0.0865s-1 with a single electron transfer. Moreover, both the oxidation and the reduction currents are linearly related with the hemoglobin concentration in the range of 1×10-8~5×10-7 mol/L. So, it can be used as an analytical method for determining hemoglobin.
1996, 7(8): 733-734
Abstract:
A new method for the determination of trace iridium with catalytic laser thermal lensing spectrometry was developed. The method has been applied to the determination of the trace iridium in the fossil of dinosaurian egg in Nanyang region, China.
A new method for the determination of trace iridium with catalytic laser thermal lensing spectrometry was developed. The method has been applied to the determination of the trace iridium in the fossil of dinosaurian egg in Nanyang region, China.
1996, 7(8): 735-736
Abstract:
Fluorescene spectra in dilute aqueous solution of a series of single chain amphiphiles with an interposed naphthalene-1, 5-dioxy group were studied to elucidate the characteristic self-assembling behavior, which indicates the abrupt change in fluorescence intensity associated with phase transition of gel to liquid crystal.
Fluorescene spectra in dilute aqueous solution of a series of single chain amphiphiles with an interposed naphthalene-1, 5-dioxy group were studied to elucidate the characteristic self-assembling behavior, which indicates the abrupt change in fluorescence intensity associated with phase transition of gel to liquid crystal.
1996, 7(8): 737-738
Abstract:
The supported gold catalysts have high activity, good resistance to moisture and sulfur poisoning for removing carbon monoxide from air at ambient temperature.
The supported gold catalysts have high activity, good resistance to moisture and sulfur poisoning for removing carbon monoxide from air at ambient temperature.
1996, 7(8): 739-740
Abstract:
Copper (Ⅱ) Schiff base complexes derived from aromatic amine and salicylaldehyde were found to be highly active catalysts for the cyclopropanation of tetramethylethylene with ethyl diazoacetate. 82% yield of cyclopropanation was obtained with one of the complexes as catalyst.
Copper (Ⅱ) Schiff base complexes derived from aromatic amine and salicylaldehyde were found to be highly active catalysts for the cyclopropanation of tetramethylethylene with ethyl diazoacetate. 82% yield of cyclopropanation was obtained with one of the complexes as catalyst.
1996, 7(8): 741-742
Abstract:
In this paper the effect of ion-exchange simplified as water handling on basic zeolite was studied. It was found that the interaction between chemisorbed water and Na+-O2- couple would increase the total number of basic sites, while weaken the intensity of each basic sites. The process can be explained by the adsorb model of organic acid on NaX presented before.
In this paper the effect of ion-exchange simplified as water handling on basic zeolite was studied. It was found that the interaction between chemisorbed water and Na+-O2- couple would increase the total number of basic sites, while weaken the intensity of each basic sites. The process can be explained by the adsorb model of organic acid on NaX presented before.
1996, 7(8): 743-744
Abstract:
The adsorb model of formic acid on NaX derived from TPD was discussed. It was showed that the adsorb sites were various exposed framework O2- centers bearing different basic intensity and spatial resistance. The h-peak was attributed to O2- near SⅢ in supercage and l-peak to O2- near SⅡ in β-cage of faujusite zeolite. The model can explain the experimental results. Meanwhile, a relative standard of basic intensity based on TPD of formic acid was founded.
The adsorb model of formic acid on NaX derived from TPD was discussed. It was showed that the adsorb sites were various exposed framework O2- centers bearing different basic intensity and spatial resistance. The h-peak was attributed to O2- near SⅢ in supercage and l-peak to O2- near SⅡ in β-cage of faujusite zeolite. The model can explain the experimental results. Meanwhile, a relative standard of basic intensity based on TPD of formic acid was founded.
1996, 7(8): 745-758
Abstract:
The electro-oxidation of ethanol on a highly preferred orientation (220) Ni electrode and a lower texture degree Ni electrode in 1 mol/L NaoH was investigated with cyclic voltammetry. The mechanism of ethanol oxidation on the highly preferred orientation Ni electrode is proposed. It is shown that the current peak of electro-oxidation of ethanol on the highly preferred orientation (220) Ni electrode is much higher than that of the lower texture degree (220) Ni electrode, Ni (Ⅲ) on the surface of the highly preferred orientation (220) Ni electrode is responsible for the oxidation of ethanol.
The electro-oxidation of ethanol on a highly preferred orientation (220) Ni electrode and a lower texture degree Ni electrode in 1 mol/L NaoH was investigated with cyclic voltammetry. The mechanism of ethanol oxidation on the highly preferred orientation Ni electrode is proposed. It is shown that the current peak of electro-oxidation of ethanol on the highly preferred orientation (220) Ni electrode is much higher than that of the lower texture degree (220) Ni electrode, Ni (Ⅲ) on the surface of the highly preferred orientation (220) Ni electrode is responsible for the oxidation of ethanol.
1996, 7(8): 749-752
Abstract:
Magnesium oxide supported polytitazane-cobalt (Ⅲ) complex has been prepared and found to be capable of catalyzing the epoxidation of styrene to form styrene oxide in 88.0% yield in the presence of isobutyraldehyde under an atmospheric pressure of molecular oxygen at room temperature. XPS data shows that the high valent cobalt (Ⅲ) is stabilized by the multidentate nitrogen ligand of polytitazane. Dichloroethane is the best solvent chosen for this reaction. The catalyst can be reused for several times without any remarkable loss in catalytic activity and selectivity.
Magnesium oxide supported polytitazane-cobalt (Ⅲ) complex has been prepared and found to be capable of catalyzing the epoxidation of styrene to form styrene oxide in 88.0% yield in the presence of isobutyraldehyde under an atmospheric pressure of molecular oxygen at room temperature. XPS data shows that the high valent cobalt (Ⅲ) is stabilized by the multidentate nitrogen ligand of polytitazane. Dichloroethane is the best solvent chosen for this reaction. The catalyst can be reused for several times without any remarkable loss in catalytic activity and selectivity.
1996, 7(8): 753-755
Abstract:
The intramolecular photochemical interaction of a series of bis-coumarinyl compounds with various alkyl chain lengths (An) has been studied in/without the presence of β-cy-clodextrin (β-CD) by fluorescence spectroscopy. The results show that both photodimerization and excimer formation can occur in the respective favourable microenvironments.
The intramolecular photochemical interaction of a series of bis-coumarinyl compounds with various alkyl chain lengths (An) has been studied in/without the presence of β-cy-clodextrin (β-CD) by fluorescence spectroscopy. The results show that both photodimerization and excimer formation can occur in the respective favourable microenvironments.
1996, 7(8): 756-758
Abstract:
The shape memory behavior of a series of PCL/MDI/BDO segmented polyurethanes of different composition is presented. The molecular weight of the PCL diols is in the range of 1600-7000. It is found that the shape memory effect of segmented polyurethanes is really related with the crystallinity of the soft segment regions and the formation of stable hard segment domains as predicted by the model proposed in our previous papers.
The shape memory behavior of a series of PCL/MDI/BDO segmented polyurethanes of different composition is presented. The molecular weight of the PCL diols is in the range of 1600-7000. It is found that the shape memory effect of segmented polyurethanes is really related with the crystallinity of the soft segment regions and the formation of stable hard segment domains as predicted by the model proposed in our previous papers.
1996, 7(8): 759-762
Abstract:
A new and simple method for evaluating the critical aggregate concentration (CAgC) by measurement of the UV absorbance of the aggregator in solution has been established.
A new and simple method for evaluating the critical aggregate concentration (CAgC) by measurement of the UV absorbance of the aggregator in solution has been established.
1996, 7(8): 763-766
Abstract:
The molecular recognition of the naphthalene derivatives of 2, 6-dimethyl-β-CD, (1);mono-[6-deoxy-6-(2-aminoethylamine)]-β-CD, (2) and mono-[6-deoxy-6-(6-aminohexylamine)]-β-CD, (3) was studied by fluorescence. The formation constants of the inclusion complexes were estimated based on the variation of fluorescent intensity and the modified Benesi-Hilde-brand equations.
The molecular recognition of the naphthalene derivatives of 2, 6-dimethyl-β-CD, (1);mono-[6-deoxy-6-(2-aminoethylamine)]-β-CD, (2) and mono-[6-deoxy-6-(6-aminohexylamine)]-β-CD, (3) was studied by fluorescence. The formation constants of the inclusion complexes were estimated based on the variation of fluorescent intensity and the modified Benesi-Hilde-brand equations.
1996, 7(8): 766-770
Abstract:
A set of regression models have been established for the inclusion of substituted benzenes by α-and β-cyclodextrin with correlations of 0.96 and 0.94, respectively. The 1nKa values calculated by the models are in agreement with those determined experimentally. The inclusion process is mainly driven by the van der Waals force and the hydrophobic interactions.
A set of regression models have been established for the inclusion of substituted benzenes by α-and β-cyclodextrin with correlations of 0.96 and 0.94, respectively. The 1nKa values calculated by the models are in agreement with those determined experimentally. The inclusion process is mainly driven by the van der Waals force and the hydrophobic interactions.
1996, 7(8): 771-772
Abstract:
An empirical equation to reveal relations between topological index (ZG) and physico-chemical properties of normal paraffins is proposed as follows:P=a lg ZG/Nx+b, where P stands for a physico-chemical property, N is the number of carbon atoms in the molecule, and ZG is the topological index proposed by Hosoya, a, b, and x are constants related to a certain physico-chemical property. Thirteen properties are calculated using this equation. The values of these properties calculated are close to those from experiments.
An empirical equation to reveal relations between topological index (ZG) and physico-chemical properties of normal paraffins is proposed as follows:P=a lg ZG/Nx+b, where P stands for a physico-chemical property, N is the number of carbon atoms in the molecule, and ZG is the topological index proposed by Hosoya, a, b, and x are constants related to a certain physico-chemical property. Thirteen properties are calculated using this equation. The values of these properties calculated are close to those from experiments.
1996, 7(8): 773-776
Abstract:
The stability constants of binary ML2+ complexes formed by Zn2+ or Cd2+ (M2+) and isoquinoline or benzimidazole (L) and ternary M (ATP) L2- complexes containing ATP in addition were determined by potentiometric pH titration in aqueous solution. It has been found that there is an intramolecular stacking interaction between the heteroaromatic N-Base ligands and the base part of ATP in the ternary complexes, this interaction may have relation to the structure of the aromatic rings of the L ligands.
The stability constants of binary ML2+ complexes formed by Zn2+ or Cd2+ (M2+) and isoquinoline or benzimidazole (L) and ternary M (ATP) L2- complexes containing ATP in addition were determined by potentiometric pH titration in aqueous solution. It has been found that there is an intramolecular stacking interaction between the heteroaromatic N-Base ligands and the base part of ATP in the ternary complexes, this interaction may have relation to the structure of the aromatic rings of the L ligands.
1996, 7(8): 777-778
Abstract:
The present paper reports nine new heteropoly compounds of tungstoti-tanophosphates containing rare earth elements, i.e., Ln2H[PTi2W10O40]·xH2O (Ln=La, Ce, Pr, Nd, Sm, Gd, Tb, Yb, Lu). The above compounds have shown good effects on restraining proliferation of MT-4 Cell and anti-HIV-1 activity with low toxicity.
The present paper reports nine new heteropoly compounds of tungstoti-tanophosphates containing rare earth elements, i.e., Ln2H[PTi2W10O40]·xH2O (Ln=La, Ce, Pr, Nd, Sm, Gd, Tb, Yb, Lu). The above compounds have shown good effects on restraining proliferation of MT-4 Cell and anti-HIV-1 activity with low toxicity.
1996, 7(8): 779-780
Abstract:
A new type of high proton conductor with the character of high conductivity and wide stable range for heat were reported, a value reaching 10-3 S·cm-1 at room tempra-ture.
A new type of high proton conductor with the character of high conductivity and wide stable range for heat were reported, a value reaching 10-3 S·cm-1 at room tempra-ture.
1996, 7(8): 781-784
Abstract:
Pattern recognition or back-propagation algorithm of three-layer artificial neural network with chemical bond parameters as features or inputs was applied to reciprocal ternary Me-. Me2-X-, X2- type. The formability of ternary compounds in molten salt type was investigated. Computerized prediction indicates that the K, Mn|Br, SO4 system can form a ternary compound. The new compound was confirmed by experimental work, and its formula is 2KBr 3MnSO4.
Pattern recognition or back-propagation algorithm of three-layer artificial neural network with chemical bond parameters as features or inputs was applied to reciprocal ternary Me-. Me2-X-, X2- type. The formability of ternary compounds in molten salt type was investigated. Computerized prediction indicates that the K, Mn|Br, SO4 system can form a ternary compound. The new compound was confirmed by experimental work, and its formula is 2KBr 3MnSO4.
