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1990 Volume 1 Issue 1
1990, 1(1): 1-4
Abstract:
meso-Nitration, chlorination and acetoxylation of ZnOEP viaanodic oxidation are reported to proceed via EE'C, ECE and EE'C mechanismrespectively.
meso-Nitration, chlorination and acetoxylation of ZnOEP viaanodic oxidation are reported to proceed via EE'C, ECE and EE'C mechanismrespectively.
1990, 1(1): 5-8
Abstract:
Heterocyclic ketene aminals 1 react with aryl azides 2 to give thetitled compounds 3, and in some cases also with the formation offused heterocycles 4.
Heterocyclic ketene aminals 1 react with aryl azides 2 to give thetitled compounds 3, and in some cases also with the formation offused heterocycles 4.
1990, 1(1): 9-12
Abstract:
The electrostatic potential of carbene and nitrene, have been calculated by ABINITIO method with 6-31G** basis set, there are positive potential regions in the directionsof vacant P orbitals, and negative regions in the directions of lone-pair electrons.Therefore, atoms in these molecules have different electric properties in differentdirections.The idea of electrophilic and nucleophilic directions of an atom in moleculesshould be introduced.
The electrostatic potential of carbene and nitrene, have been calculated by ABINITIO method with 6-31G** basis set, there are positive potential regions in the directionsof vacant P orbitals, and negative regions in the directions of lone-pair electrons.Therefore, atoms in these molecules have different electric properties in differentdirections.The idea of electrophilic and nucleophilic directions of an atom in moleculesshould be introduced.
1990, 1(1): 13-16
Abstract:
Five new diterpenes were isolated from Euphorbia sieboldiana and identified as atis-16-en-13(S)-hydroxy-3, 14-dione(Ⅰ), atis-16-en-14-oxo-13(S), 3 β-diol(Ⅱ), atisane-3-oxo-16α, 17-diol(Ⅳ), atisane-3β, 16α, 17-triol(Ⅴ)and atisane-3β-acetyl-16α, 17-diol(Ⅵ)based on the chemical, spectral evidences and X-ray diffraction.
Five new diterpenes were isolated from Euphorbia sieboldiana and identified as atis-16-en-13(S)-hydroxy-3, 14-dione(Ⅰ), atis-16-en-14-oxo-13(S), 3 β-diol(Ⅱ), atisane-3-oxo-16α, 17-diol(Ⅳ), atisane-3β, 16α, 17-triol(Ⅴ)and atisane-3β-acetyl-16α, 17-diol(Ⅵ)based on the chemical, spectral evidences and X-ray diffraction.
1990, 1(1): 17-18
Abstract:
The interaction between CH3OH and H2CO has been studied by abinitio method (6-311G basis set).It has been found that there are twopossible complexes:(Ⅰ)H-bond BrÖnsted complex CH3OH...OCH2(Ⅱ)Donorscceptor Lewis complex CH3OH...CH2P.HF/6-311G stabilization energiesfor complex(Ⅰ)and complex(Ⅱ)are 25.1 and 17.1 kJ/mol respectively.
The interaction between CH3OH and H2CO has been studied by abinitio method (6-311G basis set).It has been found that there are twopossible complexes:(Ⅰ)H-bond BrÖnsted complex CH3OH...OCH2(Ⅱ)Donorscceptor Lewis complex CH3OH...CH2P.HF/6-311G stabilization energiesfor complex(Ⅰ)and complex(Ⅱ)are 25.1 and 17.1 kJ/mol respectively.
1990, 1(1): 19-20
Abstract:
Using heavy-atom-containing xanthene dyes, benzoins can be quanti-tatively prepared by photosensitized reduction from benzils with triethyla-mine.It is an important supplement to"benzoin condensation", esp .for thosebenzoins with electron-donating substituents.
Using heavy-atom-containing xanthene dyes, benzoins can be quanti-tatively prepared by photosensitized reduction from benzils with triethyla-mine.It is an important supplement to"benzoin condensation", esp .for thosebenzoins with electron-donating substituents.
PURIFICATION AND PARTIAL CHARACTERIZATION OF POLYSACCHARIDES FROM THE POLLEN OF TYPHA ANGUSTIFILIA L
1990, 1(1): 21-22
Abstract:
Three polysaccharides TAA, TAB and TAC were purified from the pollen of Typha An-gustifilia L..TAA is mainly composed of α-L-arabinofuranose, β-D-galactose and α-D-galac-turonic acid.TAB and TAC contain the backbone mainly composed of (1→5)-linked-L-arabi-nosyl residue.
Three polysaccharides TAA, TAB and TAC were purified from the pollen of Typha An-gustifilia L..TAA is mainly composed of α-L-arabinofuranose, β-D-galactose and α-D-galac-turonic acid.TAB and TAC contain the backbone mainly composed of (1→5)-linked-L-arabi-nosyl residue.
1990, 1(1): 23-24
Abstract:
A new highly oxygenated iridoid, lamiophlomiol C, was isolated from theroots of Lamiophlomis rotata and its structure was elucidated by spectrosoopic techniquesand X-ray diffraction.
A new highly oxygenated iridoid, lamiophlomiol C, was isolated from theroots of Lamiophlomis rotata and its structure was elucidated by spectrosoopic techniquesand X-ray diffraction.
1990, 1(1): 25-26
Abstract:
Preost-Woodward hydroxylation of 2 gave the 22S, 23S-glycol(3), contrary to expectation.It is suggested that the formation of the two possibleiodonium ions(4a and 4b)are reversible, thus allowing the discriminatoryacetoxy group to follow the less hindered route, reacting with 4a virtuallyexclusively.
Preost-Woodward hydroxylation of 2 gave the 22S, 23S-glycol(3), contrary to expectation.It is suggested that the formation of the two possibleiodonium ions(4a and 4b)are reversible, thus allowing the discriminatoryacetoxy group to follow the less hindered route, reacting with 4a virtuallyexclusively.
1990, 1(1): 27-28
Abstract:
The reaction between sodium perfluoroalkanesulfinate(1)(Rf=a, Cl(CF2)4;b, Cl(CF2)6;c, Cl(CF2)8;d, n-C6F13;e, n-C8F17;f, H(CF2)4OCF2CF2)andphosphorus trichloride in acetonitrile at 0℃ resulted in the formation of anunstable intermediate, which was hydrolysed directly with aqueous sodium hydro-xide solution to give the corresponding perfluorocarboxylic acid in good yield.
The reaction between sodium perfluoroalkanesulfinate(1)(Rf=a, Cl(CF2)4;b, Cl(CF2)
1990, 1(1): 29-30
Abstract:
The chain reaction of 1, 2-dichloroethane was initiated by photosensitization of SF6 under the selective excitation using a cw CO2 laser.Vinyl chloride with high purity was produced in the reaction process.The initiation of the photosensitized chain reaction depends on the irradiated laser frequency.The mechanism of intermolecularr esonant transfer of vibrational energy has been discussed.
The chain reaction of 1, 2-dichloroethane was initiated by photosensitization of SF6 under the selective excitation using a cw CO2 laser.Vinyl chloride with high purity was produced in the reaction process.The initiation of the photosensitized chain reaction depends on the irradiated laser frequency.The mechanism of intermolecularr esonant transfer of vibrational energy has been discussed.
1990, 1(1): 31-32
Abstract:
1, 5-Bismethylene cyclooctane derivatives were synthesized by the palladium catalyzed annulation reaction of 2-methylene propane-1, 3-diol diacetate with compounds containing active methylene groups in the presence of BSA.
1, 5-Bismethylene cyclooctane derivatives were synthesized by the palladium catalyzed annulation reaction of 2-methylene propane-1, 3-diol diacetate with compounds containing active methylene groups in the presence of BSA.
1990, 1(1): 33-36
Abstract:
The adsorption of decylmethylsulfoxide (DEMS) onto carbon black and the effects of temperature, salt (NaCl) and acid (HCl) have been measured.Typical two plateaux type adsorption isotherms were obtained. Applying the two step model of surfactant adsorption on solid/liquld interface and the general adsorption isotherm equation[9]the experimental results were interpreted qualitatively and quantitatively.
The adsorption of decylmethylsulfoxide (DEMS) onto carbon black and the effects of temperature, salt (NaCl) and acid (HCl) have been measured.Typical two plateaux type adsorption isotherms were obtained. Applying the two step model of surfactant adsorption on solid/liquld interface and the general adsorption isotherm equation[9]the experimental results were interpreted qualitatively and quantitatively.
1990, 1(1): 37-38
Abstract:
Isovaleroyl oxokadsurane, a novel dibenzocyclooctadiene lignan pos-sessing a spirobenzofuranoid skeleton was isolated from the stems of Kadsura coccinea.Its structure and relative configuration were determined by X-ray diffraction analysis.
Isovaleroyl oxokadsurane, a novel dibenzocyclooctadiene lignan pos-sessing a spirobenzofuranoid skeleton was isolated from the stems of Kadsura coccinea.Its structure and relative configuration were determined by X-ray diffraction analysis.
1990, 1(1): 39-40
Abstract:
Treatment of biliverdin IXα dimethyl ester(2)with silver nitratein alkaline solution gave two violin-like tripyrrione carbaldehydes, one de-graded at C15-C16, other at C4-C5.Biliverdin IXα(1), bilirubin IXα(3)and its dimethyl ester(4)gave the same results.
Treatment of biliverdin IXα dimethyl ester(2)with silver nitratein alkaline solution gave two violin-like tripyrrione carbaldehydes, one de-graded at C15-C16, other at C4-C5.Biliverdin IXα(1), bilirubin IXα(3)and its dimethyl ester(4)gave the same results.
1990, 1(1): 41-44
Abstract:
The ESR signals of bilirubin-IXα were studied including the samples treated with free radical generating and inhibiting systems, i.e.X-X0., Fe/EDTA, SOD, mannitol/ascorbate, DTPA, KCN et al.These stable signals all comprise those originated from a semiquinone radical(g=2.0012)and superoxide radical(g11=2.041, g⊥=2.0040).The latter is shown to be bound with metal ionsespecially iron, chelated by bilirubin.The iron probably comes from bilirubin precursor---hemootobin.Active oxygen free radical scavengers may destroy these radicals.Kinetic curves of regeneration of the bilirubin radicals have been determined.Bilirubin is discussed as"active oxygen trap"in mammatians.
The ESR signals of bilirubin-IXα were studied including the samples treated with free radical generating and inhibiting systems, i.e.X-X0., Fe/EDTA, SOD, mannitol/ascorbate, DTPA, KCN et al.These stable signals all comprise those originated from a semiquinone radical(g=2.0012)and superoxide radical(g11=2.041, g⊥=2.0040).The latter is shown to be bound with metal ionsespecially iron, chelated by bilirubin.The iron probably comes from bilirubin precursor---hemootobin.Active oxygen free radical scavengers may destroy these radicals.Kinetic curves of regeneration of the bilirubin radicals have been determined.Bilirubin is discussed as"active oxygen trap"in mammatians.
1990, 1(1): 45-46
Abstract:
5-(1-Menthyloxy)-2(5-H)-furanone is used as s chiral dipolarophile for thermal asymmetric 1, 3-dipolar cycloaddition reaction with C-phenyl-N-phenyl nitrone to give the diastereomerically pure cycloaddition product.
5-(1-Menthyloxy)-2(5-H)-furanone is used as s chiral dipolarophile for thermal asymmetric 1, 3-dipolar cycloaddition reaction with C-phenyl-N-phenyl nitrone to give the diastereomerically pure cycloaddition product.
1990, 1(1): 47-48
Abstract:
Schisandrin(1)under the Ritter reaction conditions (conc.H2SO4/CH3CN)gave trace amounts of the expected acetamido derivatives(2 a, 2 b).The main product is 5 a, from intramolecular car-bonium cyclization.
Schisandrin(1)under the Ritter reaction conditions (conc.H2SO4/CH3CN)gave trace amounts of the expected acetamido derivatives(2 a, 2 b).The main product is 5 a, from intramolecular car-bonium cyclization.
1990, 1(1): 49-50
Abstract:
The major products of carbonium cyclization of 1 are 2 and 3;2 is unstable and undergoes aerial oxidation to give 4.Asimilar product(6)from 5 is somehow stabilized by the extra ben-zoyloxy group(or OH)and can be stored without deterioration.
The major products of carbonium cyclization of 1 are 2 and 3;2 is unstable and undergoes aerial oxidation to give 4.Asimilar product(6)from 5 is somehow stabilized by the extra ben-zoyloxy group(or OH)and can be stored without deterioration.
1990, 1(1): 51-54
Abstract:
γ-Amino butyric acid (GABA) and several γ-glutamyl oligopeptides were isolated and identified from water-extract of ginseng.
γ-Amino butyric acid (GABA) and several γ-glutamyl oligopeptides were isolated and identified from water-extract of ginseng.
1990, 1(1): 55-56
Abstract:
Seven diaryl ethers were synthesized with potassium fluoride coated alumina as a strong base and the addition of catalytic amount of PTC.The yield of diaryl ethers with addition of PTC was much higher than that without PTC.A discussion of the catalysis mechanism was given in this paper.
Seven diaryl ethers were synthesized with potassium fluoride coated alumina as a strong base and the addition of catalytic amount of PTC.The yield of diaryl ethers with addition of PTC was much higher than that without PTC.A discussion of the catalysis mechanism was given in this paper.
1990, 1(1): 57-58
Abstract:
Stereoselectivity was found during the coupling reaction to form 2', 5'-and 3', 5'-linked diadenylyl methylphosphonate.
Stereoselectivity was found during the coupling reaction to form 2', 5'-and 3', 5'-linked diadenylyl methylphosphonate.
1990, 1(1): 59-60
Abstract:
1-substituted-5-benzoylamino-4-pyrazolecarboxamides(2)were prepared by the reaction of 1-substituted pyrazolo[3, 4-d]-oxazinone(1)with amines in benzene.The compound 2 was refluxed with excess LiAlH4 in a mixture of THF and ether, one of the two carbamoyl groups in the molecule 2 was reduced selectively.As the results, 1-substituted-5-benzylamino-4-pyrazolecarboxamides (3) were obtained.Compounds 3reacted with Cl2PPh-X, or P(NET2)3, producing the title compounds(4).The conditions of the reactions were studied.
1-substituted-5-benzoylamino-4-pyrazolecarboxamides(2)were prepared by the reaction of 1-substituted pyrazolo[3, 4-d]-oxazinone(1)with amines in benzene.The compound 2 was refluxed with excess LiAlH4 in a mixture of THF and ether, one of the two carbamoyl groups in the molecule 2 was reduced selectively.As the results, 1-substituted-5-benzylamino-4-pyrazolecarboxamides (3) were obtained.Compounds 3reacted with Cl2PPh-X, or P(NET2)3, producing the title compounds(4).The conditions of the reactions were studied.
1990, 1(1): 61-64
Abstract:
The structure of the complex of mung bean trypsin inhibitor lysine active fragment with bovine trypsin has been determined at a resolution of 1.8 Å by A-ray crystallographic analysis and the complex model refined by restrained least-squares minimization with the data between 10 Å and 1.8 Å resolution.The current conventional R factor is 17.3%, and the model con-tains 1648 protein atoms, 219 inhibitor atoms and 126 water molecules.Themost prominent feature of the inhibitor fragment is that it does not containany alpha-helices.Most of the chain fold in an irregular fashion.The seven residues of the binding segment of the inhibitor lysine active frag-ment are in specific contact with bovine trypsin.The binding interactionand geometry around the reactive site are similar to that observed in otherstudies of trypsin-inhibitor complexes.
The structure of the complex of mung bean trypsin inhibitor lysine active fragment with bovine trypsin has been determined at a resolution of 1.8 Å by A-ray crystallographic analysis and the complex model refined by restrained least-squares minimization with the data between 10 Å and 1.8 Å resolution.The current conventional R factor is 17.3%, and the model con-tains 1648 protein atoms, 219 inhibitor atoms and 126 water molecules.Themost prominent feature of the inhibitor fragment is that it does not containany alpha-helices.Most of the chain fold in an irregular fashion.The seven residues of the binding segment of the inhibitor lysine active frag-ment are in specific contact with bovine trypsin.The binding interactionand geometry around the reactive site are similar to that observed in otherstudies of trypsin-inhibitor complexes.
1990, 1(1): 65-68
Abstract:
R(+)-Citronellal was converted into a key intermediate, (unsaturated ketone 5)in three steps, which led to 6 having the frame of arteannuic acid through intramolecular ene reaction.Further modification of 6afforded 1, 6-epimer of dihydroarteannuic acid.The configuration of 7 was determined by X-ray diffraction analysis.
R(+)-Citronellal was converted into a key intermediate, (unsaturated ketone 5)in three steps, which led to 6 having the frame of arteannuic acid through intramolecular ene reaction.Further modification of 6afforded 1, 6-epimer of dihydroarteannuic acid.The configuration of 7 was determined by X-ray diffraction analysis.
1990, 1(1): 69-70
Abstract:
3, 7-Dinitrodibenzobromonium salts were prepared directly by reaction of 4, 4'-dinitrobiphenyl with both sodium bromide and potassium persulphate in concentrated sulphuric acid.
3, 7-Dinitrodibenzobromonium salts were prepared directly by reaction of 4, 4'-dinitrobiphenyl with both sodium bromide and potassium persulphate in concentrated sulphuric acid.
1990, 1(1): 71-74
Abstract:
The main half molecule (4a) of the trichorabdal B (1) was synthesized from pentadienol (6).The key step is the intramolecular Diels-Alder reaction of 8.
The main half molecule (4a) of the trichorabdal B (1) was synthesized from pentadienol (6).The key step is the intramolecular Diels-Alder reaction of 8.
1990, 1(1): 75-78
Abstract:
The separation and identification of the ephedrines(cathine, norephe-drine, ephedrine, pseudoephedrine, methylephedrine and ethylephedrine)and theirderivatives obtained from TFAA, MSTFA, MSTFA+MBTFA and MSTFA+Ethyl acetate deriva-tization were carried out by GC/MSD.
The separation and identification of the ephedrines(cathine, norephe-drine, ephedrine, pseudoephedrine, methylephedrine and ethylephedrine)and theirderivatives obtained from TFAA, MSTFA, MSTFA+MBTFA and MSTFA+Ethyl acetate deriva-tization were carried out by GC/MSD.
1990, 1(1): 79-80
Abstract:
Compound(PH4P)[V3MP6](MPH2=o-HOC6H4SH)was obtained by reaction of VCl3 and Na2MP in ethanol in the presence of PH4PBr.It is triclinic and crystallizes in space group P1, fw=1237.3, a=14.127(4), b=14.342(4), c=15.878(4)Å;α=65.08(2), β=73.09(2), γ=78.68(2)°;V=2781.3 Å3, Z=2, dc=1.48 g/cm3.Final R factor is 0.063.The three vanadium atoms are linearly arranged and bridged by the oxygen atoms and terminally chelated by the thiolato-atoms of the six MP2-ligands in pseudo-S6 symmetry.
Compound(PH4P)[V3MP6](MPH2=o-HOC6H4SH)was obtained by reaction of VCl3 and Na2MP in ethanol in the presence of PH4PBr.It is triclinic and crystallizes in space group P1, fw=1237.3, a=14.127(4), b=14.342(4), c=15.878(4)Å;α=65.08(2), β=73.09(2), γ=78.68(2)°;V=2781.3 Å3, Z=2, dc=1.48 g/cm3.Final R factor is 0.063.The three vanadium atoms are linearly arranged and bridged by the oxygen atoms and terminally chelated by the thiolato-atoms of the six MP2-ligands in pseudo-S6 symmetry.
1990, 1(1): 81-84
Abstract:
pH-fixed titration method for the determination of weak acids and bases has been studied in this paper.It is not necessary to know the ionization constant of weak acid or base and the concentration of titrant.This method had been applied to determine phenol, 4-aminoantipyrine and glycine, whose ionization constants range from 10-10 to 10-12.The results were satisfactory.
pH-fixed titration method for the determination of weak acids and bases has been studied in this paper.It is not necessary to know the ionization constant of weak acid or base and the concentration of titrant.This method had been applied to determine phenol, 4-aminoantipyrine and glycine, whose ionization constants range from 10-10 to 10-12.The results were satisfactory.
1990, 1(1): 85-86
Abstract:
Four peptide components RP1, RP2, RP3Ⅰ and RP3Ⅱ were purified from the water-ex-tract of rape(Brassica campestris L.)pollen.The primary sequence of RP3I, with 12 amino acid residues, has been determined by Edman degradation-N-terminal dansylation.The immunopro-motive activities of the initially separated sample and RP3I have been also observed in vitro.
Four peptide components RP1, RP2, RP3Ⅰ and RP3Ⅱ were purified from the water-ex-tract of rape(Brassica campestris L.)pollen.The primary sequence of RP3I, with 12 amino acid residues, has been determined by Edman degradation-N-terminal dansylation.The immunopro-motive activities of the initially separated sample and RP3I have been also observed in vitro.
1990, 1(1): 87-90
Abstract:
An automatic procedure for building a protein polyalanine backbone from guiding alpha-carbon positions is presented here, which is different from a previously developed'spare parts'approach (Jones and Thirup, 1986;Claessens et al., 1989).In our procedure, the geometric restraint of angle N-CA-C is used to generate a list of polypeptide chains, and several filters are used later to select the best conformer.The most important filter is based upon the Ramachandran scatter plot of mainchain dihedral angles PHI and PSI.Results for all test cases aresatisfactory, with more than 95% of peptide planes correctly reconstructed and the overall root-mean-square deviation less than 0.5 angstrom compared with the refined X-ray coordinates.
An automatic procedure for building a protein polyalanine backbone from guiding alpha-carbon positions is presented here, which is different from a previously developed'spare parts'approach (Jones and Thirup, 1986;Claessens et al., 1989).In our procedure, the geometric restraint of angle N-CA-C is used to generate a list of polypeptide chains, and several filters are used later to select the best conformer.The most important filter is based upon the Ramachandran scatter plot of mainchain dihedral angles PHI and PSI.Results for all test cases aresatisfactory, with more than 95% of peptide planes correctly reconstructed and the overall root-mean-square deviation less than 0.5 angstrom compared with the refined X-ray coordinates.
1990, 1(1): 91-92
Abstract:
Tow new taxane diterpenes were isolated from the leaves and stems of Taxus chinensis.Thcir structures were established as 2-deacctyl-5-decinnamatetaxagifine and taxagifinc Ⅲ on the basis of spectroscopic analysis.
Tow new taxane diterpenes were isolated from the leaves and stems of Taxus chinensis.Thcir structures were established as 2-deacctyl-5-decinnamatetaxagifine and taxagifinc Ⅲ on the basis of spectroscopic analysis.
1990, 1(1): 93-94
Abstract:
A cyclolanostene-type triterpene and two saponins derived thereform, namely MP-C, D and F, were isolated from the acid-hydrolyzate of the mixture ofsaponins of Mussaenda pubesecus.Their structures were elucidated on the basis of chemical and UV, IR, 1H, 13C NMR and MS spectral evidence.The two newsaponins MP-D and F were named Mussaendoside A and C, respectively.
A cyclolanostene-type triterpene and two saponins derived thereform, namely MP-C, D and F, were isolated from the acid-hydrolyzate of the mixture ofsaponins of Mussaenda pubesecus.Their structures were elucidated on the basis of chemical and UV, IR, 1H, 13C NMR and MS spectral evidence.The two newsaponins MP-D and F were named Mussaendoside A and C, respectively.
1990, 1(1): 95-96
Abstract:
Lespedezaflavanone-A(1)was a new isoprene substituted flavanone which was isolated from, the root bark of Lespedeza davidii.In this paper, the total synthesis of its racemate(±)-1 was reported.
Lespedezaflavanone-A(1)was a new isoprene substituted flavanone which was isolated from, the root bark of Lespedeza davidii.In this paper, the total synthesis of its racemate(±)-1 was reported.
