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1999 Volume 10 Issue 11
1999, 10(11): 889-892
Abstract:
The benzophenone-initiated photoaddition of N-methyl amines 2 to the chiral synthon 1 proceeds in a regiospecitic and highly stereocontrolled fashion to give the C-C photoadducts containing a newly stereogenic center 3a-3c.The enantiomerically pure N-C photoadducts, amino butenolides 5a-5c have been obtained from the enantioselective photoaddition of secondary cyclic amines 4 with the chiral synthon 1 under the same conditions.
The benzophenone-initiated photoaddition of N-methyl amines 2 to the chiral synthon 1 proceeds in a regiospecitic and highly stereocontrolled fashion to give the C-C photoadducts containing a newly stereogenic center 3a-3c.The enantiomerically pure N-C photoadducts, amino butenolides 5a-5c have been obtained from the enantioselective photoaddition of secondary cyclic amines 4 with the chiral synthon 1 under the same conditions.
1999, 10(11): 893-894
Abstract:
The products of pyrrolizinones with 3-methoxyphenyl magnesium bromide were bimolecular condensation compounds, not the related alcohol, and they, were confirmed by IR, 1H-NMR, 13C-NMR, HMQC, HMBC, NOE-differ., MS and Elemental Anal.This indicated that Grignard reagent is a catalyst here.
The products of pyrrolizinones with 3-methoxyphenyl magnesium bromide were bimolecular condensation compounds, not the related alcohol, and they, were confirmed by IR, 1H-NMR, 13C-NMR, HMQC, HMBC, NOE-differ., MS and Elemental Anal.This indicated that Grignard reagent is a catalyst here.
1999, 10(11): 895-898
Abstract:
The influence of some ketones on the formation of symmetrical secondary amine N.N-bis-(3.4-dimethoxyphenylethyl)amine 1 were discussed and a new method for preparing 1 was described.
The influence of some ketones on the formation of symmetrical secondary amine N.N-bis-(3.4-dimethoxyphenylethyl)amine 1 were discussed and a new method for preparing 1 was described.
1999, 10(11): 899-902
Abstract:
Disulfides were reduced by the Sm/NiCl2, or Sm/NiCl2·6H20 system to generate thiolate anion.which reacted further with anhydrides or acyl chlorides to afford thiolesters in good yields under mild and neutral conditions.
Disulfides were reduced by the Sm/NiCl2, or Sm/NiCl2·6H20 system to generate thiolate anion.which reacted further with anhydrides or acyl chlorides to afford thiolesters in good yields under mild and neutral conditions.
1999, 10(11): 903-906
Abstract:
Various 4-alkoxypyridine-2, 6-dicarboxylic acids were synthesized starting from 2, 6 lutidine.Through aldol condensation and Michael addition, various 4-arylpyridine-2, 6 dicarboxylic acids were synthesized starting from aromatic aldehydes and 2-acetylfuran.
Various 4-alkoxypyridine-2, 6-dicarboxylic acids were synthesized starting from 2, 6 lutidine.Through aldol condensation and Michael addition, various 4-arylpyridine-2, 6 dicarboxylic acids were synthesized starting from aromatic aldehydes and 2-acetylfuran.
1999, 10(11): 907-910
Abstract:
Two new compounds, isoquinoline-1, 3-dicarboxyaldehyde and (IDA) were synthesized via 6 or 7 steps starting from benzaldehyde, or prepared via 4 steps starting from allylbenzene.
Two new compounds, isoquinoline-1, 3-dicarboxyaldehyde and (IDA) were synthesized via 6 or 7 steps starting from benzaldehyde, or prepared via 4 steps starting from allylbenzene.
1999, 10(11): 911-914
Abstract:
A new approach to the synthesis of ω-bromo-dimes was carried out by using solid/liquid transferred Wittig reactions between ω-bromobutyltriphenylphosphonium salt and α.β-unsaturated aldehydes.
A new approach to the synthesis of ω-bromo-dimes was carried out by using solid/liquid transferred Wittig reactions between ω-bromobutyltriphenylphosphonium salt and α.β-unsaturated aldehydes.
1999, 10(11): 915-916
Abstract:
The reactions of gallic acid with higher fatty alcohols are accelerated by microwaves under solvent-free conditions in the presence of p-toluenesulfonic acid to afford a high yield synthesis of higher fatty alcohol gallates.Montmorillonite K 10 are less efficient.
The reactions of gallic acid with higher fatty alcohols are accelerated by microwaves under solvent-free conditions in the presence of p-toluenesulfonic acid to afford a high yield synthesis of higher fatty alcohol gallates.Montmorillonite K 10 are less efficient.
1999, 10(11): 917-918
Abstract:
A facile synthesis of the analog of curcumin, 1, 7-bis (4-hydroxyphenyl)-3-hydroxy-l, 3-heptadien-5-one 1 was achieved.The key step, was completed through the regioselective condensation of ketone 5 and acyl chloride 7.
A facile synthesis of the analog of curcumin, 1, 7-bis (4-hydroxyphenyl)-3-hydroxy-l, 3-heptadien-5-one 1 was achieved.The key step, was completed through the regioselective condensation of ketone 5 and acyl chloride 7.
1999, 10(11): 919-920
Abstract:
Two new quinones were isolated from the aerial parts of Sphallerocarpus gracillis Their structure were determined by snectrosconic methods (HRMS, 2n NMR) and finally confirmed by X-ray crystallography.
Two new quinones were isolated from the aerial parts of Sphallerocarpus gracillis Their structure were determined by snectrosconic methods (HRMS, 2n NMR) and finally confirmed by X-ray crystallography.
1999, 10(11): 921-924
Abstract:
A new triterpenoid saponin, vaccariside A 1 was isolated from the seeds of Vaccaricr segetalis using various chromatographic methods.The structure of compound 1 was elucidated by comprehensive spectroscopic analysis as 3-0-p-D-galactopyranosyl-(1-2)-[B-D-quinovpyranosyl-(1-4)-B-D-xylopyranosyl-(1-3)]-(3-D-glucuronopyranosyl quillaic acid 28-0-B-D-glucopyranosyl-(1-3)-B-D-xylopyranosyl-(1-A)]-a-L-rhamnopyranosyl-(1-2)-3-O-acetyl-B-D-fucopyranoside.
A new triterpenoid saponin, vaccariside A 1 was isolated from the seeds of Vaccaricr segetalis using various chromatographic methods.The structure of compound 1 was elucidated by comprehensive spectroscopic analysis as 3-0-p-D-galactopyranosyl-(1-2)-[B-D-quinovpyranosyl-(1-4)-B-D-xylopyranosyl-(1-3)]-(3-D-glucuronopyranosyl quillaic acid 28-0-B-D-glucopyranosyl-(1-3)-B-D-xylopyranosyl-(1-A)]-a-L-rhamnopyranosyl-(1-2)-3-O-acetyl-B-D-fucopyranoside.
1999, 10(11): 925-928
Abstract:
Two new triterpenoid saponins were isolated from the seeds of Aesculus chinensis by preparative HPLC.On the basis of chemical evidence and spectral data, their structures were established as 21β-tigloyl-28-acetylprotoaescigenin 3β-0-[β-D-xylopyranosyl (1→2)] [β-D-glucopyranosyl (1→4)]-β-D-glucopyranosiduronic acid (isoescin Ⅱa, 1) and 21β-tigloyl-28-acetylprotoaescigenin 3β-0-[β-D-xylopyranosyl (1→2)] [β-D-glucopyranosyl (1→4)]-β-D-glucopyranosiduronic acid (isoescin 11b, 2), which are a pair of geometrical isomers.
Two new triterpenoid saponins were isolated from the seeds of Aesculus chinensis by preparative HPLC.On the basis of chemical evidence and spectral data, their structures were established as 21β-tigloyl-28-acetylprotoaescigenin 3β-0-[β-D-xylopyranosyl (1→2)] [β-D-glucopyranosyl (1→4)]-β-D-glucopyranosiduronic acid (isoescin Ⅱa, 1) and 21β-tigloyl-28-acetylprotoaescigenin 3β-0-[β-D-xylopyranosyl (1→2)] [β-D-glucopyranosyl (1→4)]-β-D-glucopyranosiduronic acid (isoescin 11b, 2), which are a pair of geometrical isomers.
1999, 10(11): 929-932
Abstract:
The interaction between dansyl-labeled pollen calmodulin (D-pCaM) and synthesized peptides was studied in the presence of Ca2+ by fluorescence spectra.It is found that Gly/L-Ala→D-Ala substitution in peptide chains caused great changes in their affinity for pCaM.Besides.our data provided evidence on the dissimilarity of different Calls although they have highlyconserved structures.A preliminary study was carried out on the effects of CaM-binding peptides on cellular signal transduction, cell proliferation, showing the participation of CaM in cell functions mentioned above.
The interaction between dansyl-labeled pollen calmodulin (D-pCaM) and synthesized peptides was studied in the presence of Ca2+ by fluorescence spectra.It is found that Gly/L-Ala→D-Ala substitution in peptide chains caused great changes in their affinity for pCaM.Besides.our data provided evidence on the dissimilarity of different Calls although they have highlyconserved structures.A preliminary study was carried out on the effects of CaM-binding peptides on cellular signal transduction, cell proliferation, showing the participation of CaM in cell functions mentioned above.
1999, 10(11): 933-936
Abstract:
Direct enantiomeric separation of all four optical isomers of 2-phenylcyclopropane carboxylate ester was first achieved on each of the three differentp-cyclodextrin chiral stationary phases (CSPs) in GC.Using these CSPs, enantiomeric excess of the products of enantioselective cyclopropanation can be determined directly, conveniently and fast.
Direct enantiomeric separation of all four optical isomers of 2-phenylcyclopropane carboxylate ester was first achieved on each of the three differentp-cyclodextrin chiral stationary phases (CSPs) in GC.Using these CSPs, enantiomeric excess of the products of enantioselective cyclopropanation can be determined directly, conveniently and fast.
1999, 10(11): 937-940
Abstract:
The ground state spins coupled through electron-rich rings of bicarbenes and binitrenes have been studied at UHF/6-31G* level. The results demonstrate that ferromagnetic coupling exists in these molecules, and electron-rich rings are the potential ferromagnetic coupling units.
The ground state spins coupled through electron-rich rings of bicarbenes and binitrenes have been studied at UHF/6-31G* level. The results demonstrate that ferromagnetic coupling exists in these molecules, and electron-rich rings are the potential ferromagnetic coupling units.
1999, 10(11): 941-944
Abstract:
In order to elucidate the unusual chemical sensitivity of binary indium bromides.the potential energy surface of the model complex InBr87- has been-studied by means of ab initio allelectron calculation with larger basis sets.The configuration is on a local maximum of the energy surface and crystal potential around In+ is soft, allowing small spontaneous distortions as a result of a second-order Jahn-Teller instability.
In order to elucidate the unusual chemical sensitivity of binary indium bromides.the potential energy surface of the model complex InBr87- has been-studied by means of ab initio allelectron calculation with larger basis sets.The configuration is on a local maximum of the energy surface and crystal potential around In+ is soft, allowing small spontaneous distortions as a result of a second-order Jahn-Teller instability.
1999, 10(11): 945-948
Abstract:
The electrochemical reduction characteristics of α-nitronaphthalene in sulfuric acid solution were first reported in this paper.The results showed that the 1-amino-5-naphthol can be prepared by electrodeduction from α-nitronaphthalene and reduction peak corresponding to the reaction of α-nitronaphthalene to 1-amino-5-naphthol was in the range of-0.40~0.60V(vs.D.H.E) on the amalgamated copper cathode in the presence of SnCl2 additives.The mechanism of α-nitronaphthalene electroreduction to 1-amino-5-naphthol was also investigated.the overall electroreduction reaction was composed of two intermediate steps and two intermediate products existed in solution.The electrochemical reduction mechanism was similar to that of nitrobenzene to para-aminophenol.
The electrochemical reduction characteristics of α-nitronaphthalene in sulfuric acid solution were first reported in this paper.The results showed that the 1-amino-5-naphthol can be prepared by electrodeduction from α-nitronaphthalene and reduction peak corresponding to the reaction of α-nitronaphthalene to 1-amino-5-naphthol was in the range of-0.40~0.60V(vs.D.H.E) on the amalgamated copper cathode in the presence of SnCl2 additives.The mechanism of α-nitronaphthalene electroreduction to 1-amino-5-naphthol was also investigated.the overall electroreduction reaction was composed of two intermediate steps and two intermediate products existed in solution.The electrochemical reduction mechanism was similar to that of nitrobenzene to para-aminophenol.
1999, 10(11): 949-952
Abstract:
In this paper, 2-(2-imidazolylazo)-5-diethylamino phenol (IZAPN) was prepared, the protonation behaviour and the condition of spectrophotometric determination of cobalt with this reagent are reported.The results show that the new colour reagent reacts with cobalt to from a stable purple red complex (1:3). However, the complex formed could be changed into another species with stable absorptivity by addition of mineral acid (1+1).The.method is highly selective and sensitive and has been applied to the direct determination of cobalt in some alloys with satisfactory results.
In this paper, 2-(2-imidazolylazo)-5-diethylamino phenol (IZAPN) was prepared, the protonation behaviour and the condition of spectrophotometric determination of cobalt with this reagent are reported.The results show that the new colour reagent reacts with cobalt to from a stable purple red complex (1:3). However, the complex formed could be changed into another species with stable absorptivity by addition of mineral acid (1+1).The.method is highly selective and sensitive and has been applied to the direct determination of cobalt in some alloys with satisfactory results.
1999, 10(11): 953-956
Abstract:
A photoluminescence material, copolymer of N-vinylcarbazole(VCz)and N, N'-bisallyl-3, 4, 9, 10-Perylenetetracarboxyl diimide (APTC) chromophores P(VCz-APTC) was synthesized.The fluorescence quenching of P(VCz-APTC) by fullerene (C60) and triethylamine was also studied.
A photoluminescence material, copolymer of N-vinylcarbazole(VCz)and N, N'-bisallyl-3, 4, 9, 10-Perylenetetracarboxyl diimide (APTC) chromophores P(VCz-APTC) was synthesized.The fluorescence quenching of P(VCz-APTC) by fullerene (C60) and triethylamine was also studied.
Spectrophotometric Investigation of Cadmium Complex Solution with m-Bromobenzenediazoaminoazobenzene
1999, 10(11): 957-960
Abstract:
The synthesis of a new ligand, m-bromobenzenediazoaminoazobenzene (m-BBDA) was carried out.The reaction between m-BBDA and cadmium(Ⅱ) was sensitive at pH over 12 and in the presence of emulsifier OP.Because of the high interference of excess of ligand β-correction theory was applied instead of the single wavelength method. This study gave the simple determination of the complex ratio, real molar absorptivity(ε)and step or cumulative stability constant (K).
The synthesis of a new ligand, m-bromobenzenediazoaminoazobenzene (m-BBDA) was carried out.The reaction between m-BBDA and cadmium(Ⅱ) was sensitive at pH over 12 and in the presence of emulsifier OP.Because of the high interference of excess of ligand β-correction theory was applied instead of the single wavelength method. This study gave the simple determination of the complex ratio, real molar absorptivity(ε)and step or cumulative stability constant (K).
1999, 10(11): 961-964
Abstract:
Excimer formation in pyrenyl labeled polystyrene has been investigated in dilute solution region.The change of the intensity ratio of excimer to monomer (Ie/Im) with increasing concentration(C), is interpreted by intrachain and interchain interactions.The double logarithmic plot of Ie/Im vs C displays two critical points, Csat about 2.5×10-3g/ml and C+ at about 3.2×10-2 g/ml.In dilute region Cs, excimer formation may be controlled by intrachain interaction.
Excimer formation in pyrenyl labeled polystyrene has been investigated in dilute solution region.The change of the intensity ratio of excimer to monomer (Ie/Im) with increasing concentration(C), is interpreted by intrachain and interchain interactions.The double logarithmic plot of Ie/Im vs C displays two critical points, Csat about 2.5×10-3g/ml and C+ at about 3.2×10-2 g/ml.In dilute region C
1999, 10(11): 965-966
Abstract:
In this paper, neodymia was added into hydrocarbon synthesis catalysts by solidmixing method to improve the activity of hydrocarbon synthesis catalyst from carbon dioxide.0.1% Nd2O3 can improve the carbon dioxide conversion and light olefin selectivity at 523 and 573K.but decrease the activity at 623K.
In this paper, neodymia was added into hydrocarbon synthesis catalysts by solidmixing method to improve the activity of hydrocarbon synthesis catalyst from carbon dioxide.0.1% Nd2O3 can improve the carbon dioxide conversion and light olefin selectivity at 523 and 573K.but decrease the activity at 623K.
1999, 10(11): 967-970
Abstract:
In the reaction of methane, carbon dioxide with oxygen to synthesis gas, conversion of CH4 was increased, but CO selectivity was reduced when CeO2 was added to Ni/Ca0-Al2O4 catalyst.The characterization of TPR, XPS, XRD and H2-TPD exhibited that, on one hand, the CeO2 promoter decreased the reduction temperature of catalyst.On the other hand, addition of CeO2 resulted in an increase in the electron density of active component Ni, and as a result, reduced the ability of CH4 deep cracking and enhanced the resistance to carbon-deposition of catalyst.In addition; the existence of CeO2 was beneficial to decrease the Ni crystal particle size.
In the reaction of methane, carbon dioxide with oxygen to synthesis gas, conversion of CH4 was increased, but CO selectivity was reduced when CeO2 was added to Ni/Ca0-Al2O4 catalyst.The characterization of TPR, XPS, XRD and H2-TPD exhibited that, on one hand, the CeO2 promoter decreased the reduction temperature of catalyst.On the other hand, addition of CeO2 resulted in an increase in the electron density of active component Ni, and as a result, reduced the ability of CH4 deep cracking and enhanced the resistance to carbon-deposition of catalyst.In addition; the existence of CeO2 was beneficial to decrease the Ni crystal particle size.
1999, 10(11): 971-972
Abstract:
Tetrabutylammonium salt of organophosphoryl derivatives of trivacant tungstophosphate of formula a-[R2PW9O34]5- (R=C6H5P(S), C6H11P(O)) have been prepared, purified and characterized by elemental analysis, IR, 31P and 83W NMR.According to spectroscopic observations and chemical analysis, the hybrid anion consists of an α-[PW9O34]9- framework on which are grafted two equivalent organophosphoryl groups through P-O-W bridges, and the IR spectral data show that these new species still retain the keggin structure.
Tetrabutylammonium salt of organophosphoryl derivatives of trivacant tungstophosphate of formula a-[R2PW9O34]5- (R=C6H5P(S), C6H11P(O)) have been prepared, purified and characterized by elemental analysis, IR, 31P and 83W NMR.According to spectroscopic observations and chemical analysis, the hybrid anion consists of an α-[PW9O34]9- framework on which are grafted two equivalent organophosphoryl groups through P-O-W bridges, and the IR spectral data show that these new species still retain the keggin structure.
1999, 10(11): 973-974
Abstract:
The salts of[(μ-RE)(μ-CO)Fe2(CO)6]-[Et3NH]+(E=S, Se, Te) react with bcnrenesulfinyl chloride to dive the μ-sulfinvl croup brideed complexes(μ-RE)(μ-PnS=O)Fe2(CO)6 in goon yeias.Wnereas the sans [(μ-RS)(μ-CO)Fe2(CO)6)-[Et3NH]+(R=t-Bu, Ph) react with carbon disulfide to yield the dithioformato-brideed anionic salts [(μ-RS)(μ-S=C-S)Fe2(CO)6)-[Et3NH]+, wmcn react in situ at tne exo-suuur atom of the ditmorormato-group with diverse α，β-unsaturated carbonyl compounds to give Michael addition products in moderate yields.
The salts of[(μ-RE)(μ-CO)Fe2(CO)6]-[Et3NH]+(E=S, Se, Te) react with bcnrenesulfinyl chloride to dive the μ-sulfinvl croup brideed complexes(μ-RE)(μ-PnS=O)Fe2(CO)6 in goon yeias.Wnereas the sans [(μ-RS)(μ-CO)Fe2(CO)6)-[Et3NH]+(R=t-Bu, Ph) react with carbon disulfide to yield the dithioformato-brideed anionic salts [(μ-RS)(μ-S=C-S)Fe2(CO)6)-[Et3NH]+, wmcn react in situ at tne exo-suuur atom of the ditmorormato-group with diverse α，β-unsaturated carbonyl compounds to give Michael addition products in moderate yields.
1999, 10(11): 975-978
Abstract:
The synthesis, structure and characterization of a new one-dimensional cyanide-bridged complex [Ni(pn)2Ni(CN)4]n·nH2O (where pn=1,2-diaminopropane) are described.The structure of this complex consists of a one-dimensional polymeric chain-Ni(pn)2-NC-Ni(CN)2-CN-Ni(pn)2-in which the Ni(Ⅱ) centers are linked by two CN groups.
The synthesis, structure and characterization of a new one-dimensional cyanide-bridged complex [Ni(pn)2Ni(CN)4]n·nH2O (where pn=1,2-diaminopropane) are described.The structure of this complex consists of a one-dimensional polymeric chain-Ni(pn)2-NC-Ni(CN)2-CN-Ni(pn)2-in which the Ni(Ⅱ) centers are linked by two CN groups.
1999, 10(11): 979-982
Abstract:
Mesoporous silica molecular sieves have been synthesized under mild conditions by using in situ prepared N, N-dimethyldodecylamine oxide as template.
Mesoporous silica molecular sieves have been synthesized under mild conditions by using in situ prepared N, N-dimethyldodecylamine oxide as template.
