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1997 Volume 8 Issue 11
1997, 8(11): 935-936
Abstract:
Double asymmetric Diels-Alder reaction of 1-(SR)-p-Tolylsulfinyl-3-penten-2-one with cyclopentadiene using a chiral titanium reagent was performed.The diastereoselectivity dependent on the size of aryl substituent involved in the chiral ligands was discussed.Absolute configuration of the cycloadducts was confirmed.Dramatic reversal of selectivity is observed.
Double asymmetric Diels-Alder reaction of 1-(SR)-p-Tolylsulfinyl-3-penten-2-one with cyclopentadiene using a chiral titanium reagent was performed.The diastereoselectivity dependent on the size of aryl substituent involved in the chiral ligands was discussed.Absolute configuration of the cycloadducts was confirmed.Dramatic reversal of selectivity is observed.
1997, 8(11): 937-938
Abstract:
The reactions of α-thiobenzoylthioformylmorpholine and compounds bearing amino group,such as diamine,aminoguanidine,semicarbazide and phenylacetylene have been explored.
The reactions of α-thiobenzoylthioformylmorpholine and compounds bearing amino group,such as diamine,aminoguanidine,semicarbazide and phenylacetylene have been explored.
1997, 8(11): 939-942
Abstract:
In this paper nine New Mannich bases of 6-fluoro-thiochromanone and eight new 3-substituted-6.8-dichloro thiochromanones were synthesized and their structures were confirmed by IR,1H-NMR and elementary analysis.Most of these compounds showed excellent antifungal activity.
In this paper nine New Mannich bases of 6-fluoro-thiochromanone and eight new 3-substituted-6.8-dichloro thiochromanones were synthesized and their structures were confirmed by IR,1H-NMR and elementary analysis.Most of these compounds showed excellent antifungal activity.
1997, 8(11): 943-944
Abstract:
The synthesis of thirteen new compounds α-[2-(2,4-dichlorophenoxy) propionyloxy]alkyl phosphonates was described.The structures of these compounds were characterized by IR,1H-NMR and MS.
The synthesis of thirteen new compounds α-[2-(2,4-dichlorophenoxy) propionyloxy]alkyl phosphonates was described.The structures of these compounds were characterized by IR,1H-NMR and MS.
1997, 8(11): 945-946
Abstract:
Seven unsymmetrical diaminodimethylsilanes were prepared.The reactions of these silylamine with benzoyl chloride indicated that in comparison with electronic,the steric effect played more important role on the reactivity of Si-N bond.As a new method,unsymmetrical diamide can be produced by the reaction of the title compounds with diacid chloride.
Seven unsymmetrical diaminodimethylsilanes were prepared.The reactions of these silylamine with benzoyl chloride indicated that in comparison with electronic,the steric effect played more important role on the reactivity of Si-N bond.As a new method,unsymmetrical diamide can be produced by the reaction of the title compounds with diacid chloride.
1997, 8(11): 947-948
Abstract:
The synthesis of selena-morpholine and its derivatives is described.
The synthesis of selena-morpholine and its derivatives is described.
1997, 8(11): 949-950
Abstract:
(-)-Methyl(4R,5S,10R)-14-methoxypodocarpa-8,11,13-triene-19-oate(1),which is the key intermediate for synthesis of diterpenoids,was synthesized from (R)-(+)-2-methyl-2-(2'-nitrovinyl)-δ-valerolactone (2).
(-)-Methyl(4R,5S,10R)-14-methoxypodocarpa-8,11,13-triene-19-oate(1),which is the key intermediate for synthesis of diterpenoids,was synthesized from (R)-(+)-2-methyl-2-(2'-nitrovinyl)-δ-valerolactone (2).
1997, 8(11): 951-952
Abstract:
(-)-Dimethyl(1R,4aS)-1,4a-dimethyl-6-nitro-1,2,3,4,4a-pentahydrofluorene-1,9-dicarboxy-late (1) was synthesized from (R)-(+)-2-methyl-2-(2'-nitrovinyl)-δ-valerolactone (2),which constitutes a formal total synthesis of (-)-gibberellin A12.
(-)-Dimethyl(1R,4aS)-1,4a-dimethyl-6-nitro-1,2,3,4,4a-pentahydrofluorene-1,9-dicarboxy-late (1) was synthesized from (R)-(+)-2-methyl-2-(2'-nitrovinyl)-δ-valerolactone (2),which constitutes a formal total synthesis of (-)-gibberellin A12.
1997, 8(11): 953-956
Abstract:
A new blend of poly (2-hydroxyethyl methacrylate) (PHEMA) with poly (ethylene glycol) (PEG) was prepared.The results from solid-state NMR indicate that the PHEMA/PEG(88:12,w/w) blend is miscible on a molecular level.
A new blend of poly (2-hydroxyethyl methacrylate) (PHEMA) with poly (ethylene glycol) (PEG) was prepared.The results from solid-state NMR indicate that the PHEMA/PEG(88:12,w/w) blend is miscible on a molecular level.
1997, 8(11): 957-960
Abstract:
A mild base-catalyzed retro-benzilic acid rearrangement of a proto-[2+2] photo-cycloadduct,formed in highly steroselective photoaddition of methyl 2,4-dioxo-pentanoate to 1,5-dimethyl-6-methylenecyclohexene,afforded a spiro[4,5] decenedione from which hinesol and agarospirol were synthesized by means of reductive elimination of α-diketone and C1-homologation.
A mild base-catalyzed retro-benzilic acid rearrangement of a proto-[2+2] photo-cycloadduct,formed in highly steroselective photoaddition of methyl 2,4-dioxo-pentanoate to 1,5-dimethyl-6-methylenecyclohexene,afforded a spiro[4,5] decenedione from which hinesol and agarospirol were synthesized by means of reductive elimination of α-diketone and C1-homologation.
1997, 8(11): 961-964
Abstract:
Two new β-dihydroagarofuran sesquiterpene polyol esters were isolated from Celastrus paniculatus.subsp.paniculatus.Their Structures were deduced on the basis of spectral analyses including 2D NMR.CO2 supercritical fluid was used in separation.
Two new β-dihydroagarofuran sesquiterpene polyol esters were isolated from Celastrus paniculatus.subsp.paniculatus.Their Structures were deduced on the basis of spectral analyses including 2D NMR.CO2 supercritical fluid was used in separation.
1997, 8(11): 965-966
Abstract:
A new spirostanol saponin,named chinenoside Ⅵ,was isolated from the bulbs of Allium chinense.On the basis of spectral data and chemical evidence,its structure was established as:25 (R)-24-O-β-D-glucopyranosyl-3β,24β-dihydroxy-5α-spirost-3-O-α-L-arabinopyranosyl-(1→6)-β-D-glucopyranoside.
A new spirostanol saponin,named chinenoside Ⅵ,was isolated from the bulbs of Allium chinense.On the basis of spectral data and chemical evidence,its structure was established as:25 (R)-24-O-β-D-glucopyranosyl-3β,24β-dihydroxy-5α-spirost-3-O-α-L-arabinopyranosyl-(1→6)-β-D-glucopyranoside.
1997, 8(11): 967-970
Abstract:
A new diterpenoid 12-epiacetyldehydrolucidusculline (1) and a new norditerpenoid alkaloid 2-hydroxydeoxyaconitine (2) were isolated from the roots of Aconitum pendulum together with eight known alkaloids aconitine (3),deoxyaconitine (4),3-acetylaconitine (5),12-epiacetyldehydronapelline (6),dehydrolucidusculline (7),dehydronapelline (8),12-epidehydronapelline (9),and noeline (10).The structures of the new alkaloids (1-2) were determined on the basis of spectral method.
A new diterpenoid 12-epiacetyldehydrolucidusculline (1) and a new norditerpenoid alkaloid 2-hydroxydeoxyaconitine (2) were isolated from the roots of Aconitum pendulum together with eight known alkaloids aconitine (3),deoxyaconitine (4),3-acetylaconitine (5),12-epiacetyldehydronapelline (6),dehydrolucidusculline (7),dehydronapelline (8),12-epidehydronapelline (9),and noeline (10).The structures of the new alkaloids (1-2) were determined on the basis of spectral method.
1997, 8(11): 971-974
Abstract:
A new monotetrahydrofuran Annonaceous acetogenin,gardnerin (1) was isolated from the roots of Goniothalamus gardneri Hook.f.et.Thoms.This compound possesses five hydroxyl groups,with two hydroxyl groups at C-8 and C-10 positions.The absolute stereochemistry at 8-OH and 10-OH positions was determined by converting 1 to its ketolactone isomer,2,4-cis/trans gardnerin.Bioactivities of this new compound against human tumor cell lines are reported.Five known acetogenin compounds gigantetrocin A and B,annonacin,goniothalamicin,isoannonacin were also found.
A new monotetrahydrofuran Annonaceous acetogenin,gardnerin (1) was isolated from the roots of Goniothalamus gardneri Hook.f.et.Thoms.This compound possesses five hydroxyl groups,with two hydroxyl groups at C-8 and C-10 positions.The absolute stereochemistry at 8-OH and 10-OH positions was determined by converting 1 to its ketolactone isomer,2,4-cis/trans gardnerin.Bioactivities of this new compound against human tumor cell lines are reported.Five known acetogenin compounds gigantetrocin A and B,annonacin,goniothalamicin,isoannonacin were also found.
1997, 8(11): 975-978
Abstract:
Based on Walters' GERM[3](Genetic Evolved Receptor Model) algorithm,an improved algorithm PARM(Pseudo Atomic Receptor Model) was put forward.PARM uses combination of genetic algorithm and cross-validation technique to produce atomic-level pseudo receptor model,based on a set of known structure-activity relationship.This algorithm has been applied to one system and afforded reasonable results.
Based on Walters' GERM[3](Genetic Evolved Receptor Model) algorithm,an improved algorithm PARM(Pseudo Atomic Receptor Model) was put forward.PARM uses combination of genetic algorithm and cross-validation technique to produce atomic-level pseudo receptor model,based on a set of known structure-activity relationship.This algorithm has been applied to one system and afforded reasonable results.
1997, 8(11): 979-982
Abstract:
Eriochrome black T and Nitrosulfophenol S were advocated as the chemical models of carcinogenic non-aminoazo compounds.The main products of their oxidative cleavage in horseradish peroxidase/H2O2 system was identified as the benezenediazonium ion,the ultimate carcinogens,which could bind to DNA.The reaction conditions were investigated preliminarily.Some inhibitors and inducers of the reaction were discovered.
Eriochrome black T and Nitrosulfophenol S were advocated as the chemical models of carcinogenic non-aminoazo compounds.The main products of their oxidative cleavage in horseradish peroxidase/H2O2 system was identified as the benezenediazonium ion,the ultimate carcinogens,which could bind to DNA.The reaction conditions were investigated preliminarily.Some inhibitors and inducers of the reaction were discovered.
1997, 8(11): 983-984
Abstract:
By the use of CPB,Cd(Ⅲ) forms a highly sensitive complex with 5-Br-PADAP in aqueous solution,molar absorptivity ε is 1.21×1051.mol-1·cm-1.Trace amount of sulphide can be determined from its effect on the complex of Cd (Ⅲ)-5-Br-PADAP-CPB,sulphide in the range 0~3.2×10-6mol dm-3 causes a decrease in absorption,that is a linear function of the concentration.For 13ng cm-3 sulphide,common metal ions such as Na+,K+,Ca2+,Mg2+,Al3+ and anions such as CO32- (24μg cm-3),S2O32-(22μg cm-3),PO43-(20μg cm-3) etc.do not interfere.A method for the indirect determination of sulphide in beer and industrial waste water with good selectivity and accuracy is described.
By the use of CPB,Cd(Ⅲ) forms a highly sensitive complex with 5-Br-PADAP in aqueous solution,molar absorptivity ε is 1.21×1051.mol-1·cm-1.Trace amount of sulphide can be determined from its effect on the complex of Cd (Ⅲ)-5-Br-PADAP-CPB,sulphide in the range 0~3.2×10-6mol dm-3 causes a decrease in absorption,that is a linear function of the concentration.For 13ng cm-3 sulphide,common metal ions such as Na+,K+,Ca2+,Mg2+,Al3+ and anions such as CO32- (24μg cm-3),S2O32-(22μg cm-3),PO43-(20μg cm-3) etc.do not interfere.A method for the indirect determination of sulphide in beer and industrial waste water with good selectivity and accuracy is described.
1997, 8(11): 985-988
Abstract:
Mono-,di-,tri-ethanolamines and di-,tri-ethylamines were used to prepare phosphate buffer at pH 2.5 and shown to be capable of enhancing the separation selectivity of chiral drug pinacidil and melittin in bee venom in capillary zone electrophoresis.The reason is due to the reduction of the average apparent mobilities of the analytes.
Mono-,di-,tri-ethanolamines and di-,tri-ethylamines were used to prepare phosphate buffer at pH 2.5 and shown to be capable of enhancing the separation selectivity of chiral drug pinacidil and melittin in bee venom in capillary zone electrophoresis.The reason is due to the reduction of the average apparent mobilities of the analytes.
1997, 8(11): 989-992
Abstract:
Two capillary electrophoresis methods were developed for the determination of the active constituents in four anti-hypertensive formulations.These active constituents are nitrendipine and atenolol in Tabellae Nile,and hydrochlorothiazide,amiloride hydrochloride,captopril,and enalapril maleate in three other tablet formulations,respectively The internal standard method was employed for quantitation with RSD between 1.2~4.3%,recoveries ranging from 93.1~101.0%.
Two capillary electrophoresis methods were developed for the determination of the active constituents in four anti-hypertensive formulations.These active constituents are nitrendipine and atenolol in Tabellae Nile,and hydrochlorothiazide,amiloride hydrochloride,captopril,and enalapril maleate in three other tablet formulations,respectively The internal standard method was employed for quantitation with RSD between 1.2~4.3%,recoveries ranging from 93.1~101.0%.
1997, 8(11): 993-996
Abstract:
A new method for preparing chemically modified gold electrode by anchoring thionine to self-assembled bi-(2-aminoethyl)-aminodithiocarboxyl acid(BADTC) monolayers through coordination with Cu2+ is described.This thionine modified electrode exhibits two new redox couples.Two protons were involved in the electrochemical process undergone by the couple I in the pH range of 5.0-10.0.The apparent surface electron transfer rate constant is about 0.050s-1.
A new method for preparing chemically modified gold electrode by anchoring thionine to self-assembled bi-(2-aminoethyl)-aminodithiocarboxyl acid(BADTC) monolayers through coordination with Cu2+ is described.This thionine modified electrode exhibits two new redox couples.Two protons were involved in the electrochemical process undergone by the couple I in the pH range of 5.0-10.0.The apparent surface electron transfer rate constant is about 0.050s-1.
1997, 8(11): 997-1000
Abstract:
Three new "tailed" porphyrins and their corresponding Mn(Ⅲ) metalloporphyrins were synthesized and characterized.The potentiometric response characteristics of the PVC membrane electrode based on the Mn(Ⅲ) complexes of the three new "tailed" porphyrins toward SCN- have been studied.
Three new "tailed" porphyrins and their corresponding Mn(Ⅲ) metalloporphyrins were synthesized and characterized.The potentiometric response characteristics of the PVC membrane electrode based on the Mn(Ⅲ) complexes of the three new "tailed" porphyrins toward SCN- have been studied.
1997, 8(11): 1001-1002
Abstract:
RLT filtration——a new method to separate faradaic current from extraneous currents applied in potential step scan voltammetry was first proposed.The current equation of potential step scan voltammetry has been deduced.The theory and the process of RLT filtration are presented.The curve shapes and the properties of normal pulse voltammetry of reversible reactions have been studied.
RLT filtration——a new method to separate faradaic current from extraneous currents applied in potential step scan voltammetry was first proposed.The current equation of potential step scan voltammetry has been deduced.The theory and the process of RLT filtration are presented.The curve shapes and the properties of normal pulse voltammetry of reversible reactions have been studied.
1997, 8(11): 1003-1004
Abstract:
By means of changing the detection angle,the molecular conformation of a new type of polymer surfactant,acrylamide-poly(oxyethylene alkyl ether)acrylate-anionic monomer random copolymer,was studied by x-ray photoelectron spectroscopy(XPS) in detail.
By means of changing the detection angle,the molecular conformation of a new type of polymer surfactant,acrylamide-poly(oxyethylene alkyl ether)acrylate-anionic monomer random copolymer,was studied by x-ray photoelectron spectroscopy(XPS) in detail.
1997, 8(11): 1005-1006
Abstract:
Hydrogen diffusion coefficients in amorphous Ti0.88Ni1.00 film were measured using electrochemical permeation technique.Diffusion coefficients increased with increasing hydrogen concentration.Activation energy of hydrogen diffusion was determined through measurement of the steady state anodic diffusion current density as a function of temperature,and an equation was derived to calculate the activation energy.
Hydrogen diffusion coefficients in amorphous Ti0.88Ni1.00 film were measured using electrochemical permeation technique.Diffusion coefficients increased with increasing hydrogen concentration.Activation energy of hydrogen diffusion was determined through measurement of the steady state anodic diffusion current density as a function of temperature,and an equation was derived to calculate the activation energy.
1997, 8(11): 1007-1010
Abstract:
Multiply charged ions of Ar and NO were observed in MPI experiment of NO/Ar with TOF-MS.A delayable pulsed acceleration field was applied to investigate the effect of the photoelectrons on the formation of the multiply charged ions.The multiply charged ions were suggested to be produced by photoelectron impact ionization,in the region between the extractor grid and the repeller plate,step by step,from neutral species and lower charged ions.The 50-60ns of FWHM of the ion peaks implies that the pulse width of the photoelectrons should be shorter considering the broadening effect during the ionization process.
Multiply charged ions of Ar and NO were observed in MPI experiment of NO/Ar with TOF-MS.A delayable pulsed acceleration field was applied to investigate the effect of the photoelectrons on the formation of the multiply charged ions.The multiply charged ions were suggested to be produced by photoelectron impact ionization,in the region between the extractor grid and the repeller plate,step by step,from neutral species and lower charged ions.The 50-60ns of FWHM of the ion peaks implies that the pulse width of the photoelectrons should be shorter considering the broadening effect during the ionization process.
1997, 8(11): 1011-1012
Abstract:
Two μ-oxamido complexes,[Cu(oxae)Fe(phen)2]SO4(1) and[Cu(oxae)Fe-(NO2-phen)2]SO4(2) were synthesized and characterized.The magnetism of complex (1) was studied.
Two μ-oxamido complexes,[Cu(oxae)Fe(phen)2]SO4(1) and[Cu(oxae)Fe-(NO2-phen)2]SO4(2) were synthesized and characterized.The magnetism of complex (1) was studied.
