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1997 Volume 8 Issue 4
1997, 8(4): 267-268
Abstract:
The addition reaction of ω-bromoacetophenone to aldimines by indium metal in THF-H2O gave β-aminoketones.
The addition reaction of ω-bromoacetophenone to aldimines by indium metal in THF-H2O gave β-aminoketones.
1997, 8(4): 269-270
Abstract:
The stereochemistry of thionation reaction of 2-substituted-4-aryl-5,5-dimethyl-1.3.2-dioxaphosphorian-ones 1a-f with Lawessen's reagent (LR) was reported in this paper.The results indicated that the thionation reaction of LR proceeded predominantly with retention of configuration.The mechanism leading to retention was proposed by assuming a cyclic pentacoordinated intermidiate.
The stereochemistry of thionation reaction of 2-substituted-4-aryl-5,5-dimethyl-1.3.2-dioxaphosphorian-ones 1a-f with Lawessen's reagent (LR) was reported in this paper.The results indicated that the thionation reaction of LR proceeded predominantly with retention of configuration.The mechanism leading to retention was proposed by assuming a cyclic pentacoordinated intermidiate.
1997, 8(4): 271-274
Abstract:
A novel ipso electrophlic substitution of 1-bromomethyl-4-t-butyl-2,6-dimethylbenzene 1 with nitric acid in alcohol,which gives ipso-bromination product of 1-bromo-4-t-butyl-2,6-dimethylbenzene 2,is described,and a possible mechanism for this reaction is investigated.
A novel ipso electrophlic substitution of 1-bromomethyl-4-t-butyl-2,6-dimethylbenzene 1 with nitric acid in alcohol,which gives ipso-bromination product of 1-bromo-4-t-butyl-2,6-dimethylbenzene 2,is described,and a possible mechanism for this reaction is investigated.
1997, 8(4): 275-276
Abstract:
The title compound was synthesized by the reaction of adipyl chloride with cyclohexanone piperidine enamine and its structure was finally confirmed by the single-crystal determination in addition to conventional IR,1HNMR and elemental analysis.
The title compound was synthesized by the reaction of adipyl chloride with cyclohexanone piperidine enamine and its structure was finally confirmed by the single-crystal determination in addition to conventional IR,1HNMR and elemental analysis.
1997, 8(4): 277-280
Abstract:
Compound 2 with 14β-hydroxyl group was successfully converted into its epimerized α-counterpart via oxidation-reduction.The elimination product (6) was auto-oxidized to epoxide 8,even in the solid state.
Compound 2 with 14β-hydroxyl group was successfully converted into its epimerized α-counterpart via oxidation-reduction.The elimination product (6) was auto-oxidized to epoxide 8,even in the solid state.
1997, 8(4): 281-284
Abstract:
An intramolecular nucleophilic substitution of carbon anion to cyclic sulfate was first employed in asymmetric synthesis of (+)-(3R,4S,5R,7S)-neoclausenamide 1 which is a novel hepatoprotective lactam isolated from the dry leaves of Chinese folk medicine Clausena lansium (Lour) Skeel.The regioselectivity of β-attack to this cyclic sulfate,just like its epoxide counterpart,was attributed to the increased reactivity of β-position by the phenyl group.
An intramolecular nucleophilic substitution of carbon anion to cyclic sulfate was first employed in asymmetric synthesis of (+)-(3R,4S,5R,7S)-neoclausenamide 1 which is a novel hepatoprotective lactam isolated from the dry leaves of Chinese folk medicine Clausena lansium (Lour) Skeel.The regioselectivity of β-attack to this cyclic sulfate,just like its epoxide counterpart,was attributed to the increased reactivity of β-position by the phenyl group.
1997, 8(4): 285-288
Abstract:
Two new indolinospirobenzopyrans bearing monoaza-benzo-15-C-5 were synthesized.And they were determined by IR,1H NMR and MS.
Two new indolinospirobenzopyrans bearing monoaza-benzo-15-C-5 were synthesized.And they were determined by IR,1H NMR and MS.
1997, 8(4): 289-290
Abstract:
The γ-oxo vinyliminophosphorane 3 was prepared for the first time from the Staudinger reaction of vinyl azide 2 and triphenylphosphine.The reactivity of 3 was studied.
The γ-oxo vinyliminophosphorane 3 was prepared for the first time from the Staudinger reaction of vinyl azide 2 and triphenylphosphine.The reactivity of 3 was studied.
1997, 8(4): 291-292
Abstract:
The two new diarylheptanoids,1,7-bis(4-hydroxyphenyl)-1,4,6-heptatriene-3-one (1) and aecrogenin G (2) were synthesized starting from 4-hydroxybenzaldehyde (3) and acetone.
The two new diarylheptanoids,1,7-bis(4-hydroxyphenyl)-1,4,6-heptatriene-3-one (1) and aecrogenin G (2) were synthesized starting from 4-hydroxybenzaldehyde (3) and acetone.
1997, 8(4): 293-294
Abstract:
Howiinol A,an active antitumor constituent from the root and stem bark of Goniothamus howii Meer.(Annoaceae) has been synthesized in nine steps from α-D-glucoheptonic γ-lactone with an overall yield of 12.4%;The absolute configuration of natural howiinol A is further confirmed.
Howiinol A,an active antitumor constituent from the root and stem bark of Goniothamus howii Meer.(Annoaceae) has been synthesized in nine steps from α-D-glucoheptonic γ-lactone with an overall yield of 12.4%;The absolute configuration of natural howiinol A is further confirmed.
1997, 8(4): 295-298
Abstract:
Nine new derivatives of 7 β-(5-methyl-1-aryl-1H-1,2,3-triazoly-4-carboxamido) cephalosporins were synthesized by acylation of 7 β-amino group of 7-ACA,7-ADCA and 7-ACT with 5-methyl-1-aryl-1H-1,2,3-triazoly-4-formyl chloride.The structure of the compounds were confirmed by elementary analysis IR,1HNMR and FAB-MS.Some of them showed significant antibacterial activity.
Nine new derivatives of 7 β-(5-methyl-1-aryl-1H-1,2,3-triazoly-4-carboxamido) cephalosporins were synthesized by acylation of 7 β-amino group of 7-ACA,7-ADCA and 7-ACT with 5-methyl-1-aryl-1H-1,2,3-triazoly-4-formyl chloride.The structure of the compounds were confirmed by elementary analysis IR,1HNMR and FAB-MS.Some of them showed significant antibacterial activity.
1997, 8(4): 299-302
Abstract:
The cleavage activity of histidine on RNA and DNA was tested.It was found that histidine could cleave RNA,but not DNA.The cleavage mechanism was proposed to be involved in the hydrolysis of the phosphodiester backbone.
The cleavage activity of histidine on RNA and DNA was tested.It was found that histidine could cleave RNA,but not DNA.The cleavage mechanism was proposed to be involved in the hydrolysis of the phosphodiester backbone.
1997, 8(4): 303-304
Abstract:
Oxyphosphorane reacted with glucose to give disaccharide which was confirmed by FAB-MS and 13C-NMR.The mechanism for formation of oligosaccharides through the participation of phosphorus was proposed.
Oxyphosphorane reacted with glucose to give disaccharide which was confirmed by FAB-MS and 13C-NMR.The mechanism for formation of oligosaccharides through the participation of phosphorus was proposed.
1997, 8(4): 305-308
Abstract:
the synthesis of seven new benzyl substituted titanocene complexes and their novel intramolecular cyclization promoted by halides is reported.
the synthesis of seven new benzyl substituted titanocene complexes and their novel intramolecular cyclization promoted by halides is reported.
1997, 8(4): 309-312
Abstract:
Rivanol(RVN) binds to the double helical DNA with a high affinity.Strong hypochromism and appreciable red shifts in the absorption spectra can be observed when RVN binds to CT DNA.The results of absorption spectra,KI quenching studies,fluorescence polarization measurements,competitive binding studies,and thermal denaturation experiments suggested that the interaction between RVN and DNA be intercalative.
Rivanol(RVN) binds to the double helical DNA with a high affinity.Strong hypochromism and appreciable red shifts in the absorption spectra can be observed when RVN binds to CT DNA.The results of absorption spectra,KI quenching studies,fluorescence polarization measurements,competitive binding studies,and thermal denaturation experiments suggested that the interaction between RVN and DNA be intercalative.
1997, 8(4): 313-314
Abstract:
A new bisindole alkaloid,melaxillarinine,was isolated from the roots of Melodinus axillaris.Its structure was established on the basis of spectral analysis.
A new bisindole alkaloid,melaxillarinine,was isolated from the roots of Melodinus axillaris.Its structure was established on the basis of spectral analysis.
1997, 8(4): 315-316
Abstract:
A new benzofuranosesquiterpene dimer,named virgaurin B,has been isolated from the roots of Ligularia virgaurea and its structure has been elucidated by spectroscopic evidence.
A new benzofuranosesquiterpene dimer,named virgaurin B,has been isolated from the roots of Ligularia virgaurea and its structure has been elucidated by spectroscopic evidence.
1997, 8(4): 317-318
Abstract:
One new prenylated flavonol,7,8-(2",2"-dimethylpyrano)-5,3',4'-trihydroxy-3-methoxylflavone was isolated from Hypericum japonicum.The chemical structure was determined by spectroscopic methods.
One new prenylated flavonol,7,8-(2",2"-dimethylpyrano)-5,3',4'-trihydroxy-3-methoxylflavone was isolated from Hypericum japonicum.The chemical structure was determined by spectroscopic methods.
1997, 8(4): 319-322
Abstract:
The kinetics of protonolysis of o-substituted phenylmercuric chlorides,o-XC6H4HgCl (X=H, CH3, CH3O, C2H5O, CF3, COOC2H5, Cl, Br, F, NO2), by hydrochloric acid in the presence of sodium iodide as catalyst have been studied in ethanol.The reaction has been found to be second order overall,first order in each reactant.The rate constants k measured at the same temperature may be arranged in the following order: C2H5O > CH3O > CH3 > H > CO2C2H5 > F > Cl > Br > CF3 > NO2.
The kinetics of protonolysis of o-substituted phenylmercuric chlorides,o-XC6H4HgCl (X=H, CH3, CH3O, C2H5O, CF3, COOC2H5, Cl, Br, F, NO2), by hydrochloric acid in the presence of sodium iodide as catalyst have been studied in ethanol.The reaction has been found to be second order overall,first order in each reactant.The rate constants k measured at the same temperature may be arranged in the following order: C2H5O > CH3O > CH3 > H > CO2C2H5 > F > Cl > Br > CF3 > NO2.
1997, 8(4): 323-326
Abstract:
Semi-empirical method PM3 was used to study the geometry and vibrational spectrum of N-(2-hydroxy-1-naphthyl-methylene)-1-pyrenamine (NPY) with the intermediate hydrogen bond.Results are comparable to experimentations.Based on results of both NPY and its model,N-(2-hydroxy-1-naphthyl-methylene) aniline.it was found that the N-(2-hydroxy-1-naphthyl-methylene) group is principally responsible for the special hydrogen bonding through conjugation effect.
Semi-empirical method PM3 was used to study the geometry and vibrational spectrum of N-(2-hydroxy-1-naphthyl-methylene)-1-pyrenamine (NPY) with the intermediate hydrogen bond.Results are comparable to experimentations.Based on results of both NPY and its model,N-(2-hydroxy-1-naphthyl-methylene) aniline.it was found that the N-(2-hydroxy-1-naphthyl-methylene) group is principally responsible for the special hydrogen bonding through conjugation effect.
1997, 8(4): 327-330
Abstract:
The enol contents and equilibrium constants for keto-enol tautomerism of ethyl acetoacetate in supercritical (SC) CO2 with and without cosolvent ethanol and in various liquid solvents were investigated by UV spectroscopy.The local dielectric constant about the solute in SC CO2/ethanol system was obtained through the correlation between Gibbs free energy of tautomerism and Onsager-Kirkwood solvent quantin.The great difference between local dielectric constant and that calculated from homogeneous dielectric medium theory suggests clustering of the cosolvent around the solute.
The enol contents and equilibrium constants for keto-enol tautomerism of ethyl acetoacetate in supercritical (SC) CO2 with and without cosolvent ethanol and in various liquid solvents were investigated by UV spectroscopy.The local dielectric constant about the solute in SC CO2/ethanol system was obtained through the correlation between Gibbs free energy of tautomerism and Onsager-Kirkwood solvent quantin.The great difference between local dielectric constant and that calculated from homogeneous dielectric medium theory suggests clustering of the cosolvent around the solute.
1997, 8(4): 331-334
Abstract:
By using chlorpromazine as a new color reagent,spectrophotometric reactions with vanadium(Ⅴ) have been studied.In the medium of 0.25 mol·L-1 of H2SO4,chlorpromazine reacts with vanadium(Ⅴ) at room temperature to form a bright red complex,which exhibits a maximum absorption at 520 nm.Beer's law is obeyed in the concentration range of 0-2 μg and 2-40 μg V(Ⅴ)/10mL with molar absorptivities of 5.10×103 and 1.02×104L·mol-1·cm-1,respectively.
By using chlorpromazine as a new color reagent,spectrophotometric reactions with vanadium(Ⅴ) have been studied.In the medium of 0.25 mol·L-1 of H2SO4,chlorpromazine reacts with vanadium(Ⅴ) at room temperature to form a bright red complex,which exhibits a maximum absorption at 520 nm.Beer's law is obeyed in the concentration range of 0-2 μg and 2-40 μg V(Ⅴ)/10mL with molar absorptivities of 5.10×103 and 1.02×104L·mol-1·cm-1,respectively.
1997, 8(4): 335-338
Abstract:
This work describes three crown ether-coated piezoelectric crystal sensors for detection of carboxylic acid vapours.All three have excellent reproducibility and stability (lasting for at least 100 days).Two of them show good sensitivity (137-1500Hz/mg/L) and high selectivity.Cis-diamino-dibenzo-18-crown-6 can be used as the coating material for the detection of formic acid.The effect of crown ethers structure on the detection sensitivity and selectivity for acid vapours was discussed.
This work describes three crown ether-coated piezoelectric crystal sensors for detection of carboxylic acid vapours.All three have excellent reproducibility and stability (lasting for at least 100 days).Two of them show good sensitivity (137-1500Hz/mg/L) and high selectivity.Cis-diamino-dibenzo-18-crown-6 can be used as the coating material for the detection of formic acid.The effect of crown ethers structure on the detection sensitivity and selectivity for acid vapours was discussed.
1997, 8(4): 339-342
Abstract:
The traditional deoxygenation techniques for cyclodextrin induced room temperature phosphorescence (CD-RTP) include N2(g) purging and Na2SO3 chemical deoxygenation.In this paper,with 1-bromocyclohexane (1-BrCH) as an external heavy atom perturber,7,8-benzoquinoline (7,8-BQ) was used as a model compound,hydrogen and carbon dioxide are used for deoxygenation in CD-RTP and compared with two traditional deoxygenation techniques.The results show that the new deoxygenation techniques have obvious advantages such as simpler facilities,faster speed of deoxygenation and wider acidity range etc.
The traditional deoxygenation techniques for cyclodextrin induced room temperature phosphorescence (CD-RTP) include N2(g) purging and Na2SO3 chemical deoxygenation.In this paper,with 1-bromocyclohexane (1-BrCH) as an external heavy atom perturber,7,8-benzoquinoline (7,8-BQ) was used as a model compound,hydrogen and carbon dioxide are used for deoxygenation in CD-RTP and compared with two traditional deoxygenation techniques.The results show that the new deoxygenation techniques have obvious advantages such as simpler facilities,faster speed of deoxygenation and wider acidity range etc.
1997, 8(4): 343-344
Abstract:
Abnormal IR spectra of CO adsorbed at the surface of glass carbon electrode modified with polypyrrole film with Pt microparticles are reported.
Abnormal IR spectra of CO adsorbed at the surface of glass carbon electrode modified with polypyrrole film with Pt microparticles are reported.
1997, 8(4): 345-346
Abstract:
A new type of molecular imprinting stationary phase was prepared by using R-(+)-α-methylbenzylamine as the print molecule.Experiments of high performance liquid chromatography show that the new stationary phase has high enantio-selectivity and discriminates (R,S)-(±)-α-methylbenzylamine successfully with α value of 1.67.
A new type of molecular imprinting stationary phase was prepared by using R-(+)-α-methylbenzylamine as the print molecule.Experiments of high performance liquid chromatography show that the new stationary phase has high enantio-selectivity and discriminates (R,S)-(±)-α-methylbenzylamine successfully with α value of 1.67.
1997, 8(4): 347-350
Abstract:
Complete active space multiconfiguration self-consistent-field (CAS-MCSCF) calculations are carried out on the ground state(1∑g+) of W2.The spectroscopic properties (Re=2.078A. De=4.224eV and ωe=304.3cm-1) and the potential energy curve of the 1∑g+ state are reported.The calculations predict the W-W bond order of 5.02.
Complete active space multiconfiguration self-consistent-field (CAS-MCSCF) calculations are carried out on the ground state(1∑g+) of W2.The spectroscopic properties (Re=2.078A. De=4.224eV and ωe=304.3cm-1) and the potential energy curve of the 1∑g+ state are reported.The calculations predict the W-W bond order of 5.02.
1997, 8(4): 351-352
Abstract:
The electronic structure of Co6(μ6-C)(μ3-S)2(CO)12 molecule has been calculated by DV-Xα method.The results show that the reaction mechanism of CS2 and Co2(CO)8 in synthesis seems only to undergo the additive and decarbonyl processes.The other result worthy of being mentioned is the calculated atomic charges that are Co0.3+,S1.29+,μ6-C1.16-,C0.06- and O0.21-.S atom has not only the positive charge but also four times as much as that of Co atom.This is not in accordance with the electronegativities of 1.7 and 2.5 respectively for Co and S atom.
The electronic structure of Co6(μ6-C)(μ3-S)2(CO)12 molecule has been calculated by DV-Xα method.The results show that the reaction mechanism of CS2 and Co2(CO)8 in synthesis seems only to undergo the additive and decarbonyl processes.The other result worthy of being mentioned is the calculated atomic charges that are Co0.3+,S1.29+,μ6-C1.16-,C0.06- and O0.21-.S atom has not only the positive charge but also four times as much as that of Co atom.This is not in accordance with the electronegativities of 1.7 and 2.5 respectively for Co and S atom.
1997, 8(4): 353-356
Abstract:
Thirteen kinds of binary and ternary complexes of rare earth (Gd,Eu,Tb) with ortho (para) aminobenzoic acid and 1,10——phenanthroline were synthesized and characterized.The phosphorescence spectra and lifetimes of gadolinium complexes were measured and the lowest triplet state energies of ligands and the energy transfer efficiencies between ligands were determined.The luminescence properties and intramolecular energy transfer of these complexes were studied in details.
Thirteen kinds of binary and ternary complexes of rare earth (Gd,Eu,Tb) with ortho (para) aminobenzoic acid and 1,10——phenanthroline were synthesized and characterized.The phosphorescence spectra and lifetimes of gadolinium complexes were measured and the lowest triplet state energies of ligands and the energy transfer efficiencies between ligands were determined.The luminescence properties and intramolecular energy transfer of these complexes were studied in details.
1997, 8(4): 357-360
Abstract:
In this paper,evidences of strong interaction between several tris-bipyridyl complexes and Nafion matrix are provided by UV-VIS and FTIR spectra.The studied counterions also show electrosiatic interaction with the bonded -SO3- groups,as indicated by the shifting of γSso3- to lower wave number.The most probable location of these complexes seems to be near the interface between the fluorocarbon back bone and the ionic cluster region.
In this paper,evidences of strong interaction between several tris-bipyridyl complexes and Nafion matrix are provided by UV-VIS and FTIR spectra.The studied counterions also show electrosiatic interaction with the bonded -SO3- groups,as indicated by the shifting of γSso3- to lower wave number.The most probable location of these complexes seems to be near the interface between the fluorocarbon back bone and the ionic cluster region.
