Login In
1999 Volume 10 Issue 9
Enantioselective Addition of Diethylzinc to Benzaldehyde by Catalysts of Chiral Heterocyclic Ligands
1999, 10(9): 717-718
Abstract:
Several kinds of chiral heterocyclic ligands without hydroxyl group have been synthesized and used as catalysts for the asymmetric addition of diethylzinc to benzaldehyde. These ligands promoted the formation of (S)-l-phenylpropanols in good yields and medium to good enanlioselectivities(50~86%ee.)
Several kinds of chiral heterocyclic ligands without hydroxyl group have been synthesized and used as catalysts for the asymmetric addition of diethylzinc to benzaldehyde. These ligands promoted the formation of (S)-l-phenylpropanols in good yields and medium to good enanlioselectivities(50~86%ee.)
1999, 10(9): 719-722
Abstract:
A new phosphorylating reagent, N,N-di-isopropyl-O,O-di-p-methoxybenzylphosphor-amidite was synthesized from diisopropylamino dichlorophosphine and p-methoxybenzyl alcohol for preparing phosphatydyl inositol polyphosphate particularly with unsaturated components.
A new phosphorylating reagent, N,N-di-isopropyl-O,O-di-p-methoxybenzylphosphor-amidite was synthesized from diisopropylamino dichlorophosphine and p-methoxybenzyl alcohol for preparing phosphatydyl inositol polyphosphate particularly with unsaturated components.
1999, 10(9): 723-726
Abstract:
Aminomethyl arylsulfides are synthesized through nucleophilic substitution of a benzotriazolate anion by thiolates promoted by samarium diiodide.
Aminomethyl arylsulfides are synthesized through nucleophilic substitution of a benzotriazolate anion by thiolates promoted by samarium diiodide.
1999, 10(9): 727-728
Abstract:
The hydrolysis products of tetrahydrofolate model compound 4 were a mixture of 6 and 7 and the rearrangement reaction between 6 and 7 via 5 was in a state of equilibrium. confirmed by 1HNMR and IR spectra.
The hydrolysis products of tetrahydrofolate model compound 4 were a mixture of 6 and 7 and the rearrangement reaction between 6 and 7 via 5 was in a state of equilibrium. confirmed by 1HNMR and IR spectra.
1999, 10(9): 729-730
Abstract:
In the presence of cadmium(Ⅱ) chloride-metallic samarium, α-bromoacetophenone reacts with aldehydes in THF-H20 under mild conditions to givep-hydroxy ketones in good yields.
In the presence of cadmium(Ⅱ) chloride-metallic samarium, α-bromoacetophenone reacts with aldehydes in THF-H20 under mild conditions to givep-hydroxy ketones in good yields.
1999, 10(9): 731-732
Abstract:
Asymmetric 6-substituted-2-methoxy-4-(2,4-dichlorophenyl)-4H-1,3,2-benzodioxa-phosphorin 2-sulfides were prepared from intramolecular cyclization. The diastereomers were separated by column chromatography and fractional crystallization. Their structures were characterized on the basis of 1H NMR, 31P NMR and x-ray diffraction analysis.
Asymmetric 6-substituted-2-methoxy-4-(2,4-dichlorophenyl)-4H-1,3,2-benzodioxa-phosphorin 2-sulfides were prepared from intramolecular cyclization. The diastereomers were separated by column chromatography and fractional crystallization. Their structures were characterized on the basis of 1H NMR, 31P NMR and x-ray diffraction analysis.
1999, 10(9): 733-734
Abstract:
Stereoselective synthesis of sultam 8 was reported. The overall yield in a sequence of 4 steps is 27.5%.
Stereoselective synthesis of sultam 8 was reported. The overall yield in a sequence of 4 steps is 27.5%.
1999, 10(9): 735-736
Abstract:
A new and convenient chiral synthesis of naturally occurring(-)-(S)-4-hydroxy-2-pyrrolidinone from (S)-malic acid was reported.
A new and convenient chiral synthesis of naturally occurring(-)-(S)-4-hydroxy-2-pyrrolidinone from (S)-malic acid was reported.
1999, 10(9): 737-738
Abstract:
Naturally occurring 9-(5-pentyl-2-furyl) nonanoic acid which was synthesized through tive steps in about 20% overall yield by using 5-trimethylsilyl-2-furancarboxaldehyde as a starting material.
Naturally occurring 9-(5-pentyl-2-furyl) nonanoic acid which was synthesized through tive steps in about 20% overall yield by using 5-trimethylsilyl-2-furancarboxaldehyde as a starting material.
1999, 10(9): 739-740
Abstract:
A new series of compounds, 1-[(O,O-diphenyl phosphonyl)arylmethylene aminocarbo-nylmethyl]uracils, were synthesized in yield of 54.6-72.0% with DCC/BtOH as the coupling reagent, and their biological activities are being tested.
A new series of compounds, 1-[(O,O-diphenyl phosphonyl)arylmethylene aminocarbo-nylmethyl]uracils, were synthesized in yield of 54.6-72.0% with DCC/BtOH as the coupling reagent, and their biological activities are being tested.
1999, 10(9): 741-744
Abstract:
The synthesis and properties of D-thymidylyl (3'→5')L-thymidine (D/L-TpT) are described.
The synthesis and properties of D-thymidylyl (3'→5')L-thymidine (D/L-TpT) are described.
1999, 10(9): 745-748
Abstract:
The formation of charge transfer complexes (CTC) between C60 with metallophthalocyanine (MPc. M=Zn. Co) has been investigated in three mixed organic solvents. fhe MPc-C60 CTC were characterized by using UV-Vis and fluorescence spectra. The formation eduilibrium constants (K) of CTC and their stoichiometry were determined. The foundation of CTC leads to a remarkable enhancement of the photoelectrochemical property. The CTC will provide a potential opportuniy to develop a new applicable photoelectric material.
The formation of charge transfer complexes (CTC) between C60 with metallophthalocyanine (MPc. M=Zn. Co) has been investigated in three mixed organic solvents. fhe MPc-C60 CTC were characterized by using UV-Vis and fluorescence spectra. The formation eduilibrium constants (K) of CTC and their stoichiometry were determined. The foundation of CTC leads to a remarkable enhancement of the photoelectrochemical property. The CTC will provide a potential opportuniy to develop a new applicable photoelectric material.
1999, 10(9): 749-750
Abstract:
A convenient and stercoselcctive approach to the synthesis of (3S. 4R, 6S)-2-oxo-3.4-dihvdrosy-6-methyl-octanatc derivative. a kcy intermediate for the synthesis of IIIV-1 protease inhibitor of didcmnaketals analogue, has been developed successfully from L-(-)-mcnthone.
A convenient and stercoselcctive approach to the synthesis of (3S. 4R, 6S)-2-oxo-3.4-dihvdrosy-6-methyl-octanatc derivative. a kcy intermediate for the synthesis of IIIV-1 protease inhibitor of didcmnaketals analogue, has been developed successfully from L-(-)-mcnthone.
1999, 10(9): 751-754
Abstract:
A ground state model about an asymmetry hydrogenation of methyl pyruvate over Pl-nanocluster catalyst with a modifier cinconidine has been built. The role of the modifier in the catalytic process is explained.
A ground state model about an asymmetry hydrogenation of methyl pyruvate over Pl-nanocluster catalyst with a modifier cinconidine has been built. The role of the modifier in the catalytic process is explained.
1999, 10(9): 755-758
Abstract:
In the present study we investigated two groups of small molecular tyrosine kinase phosphorylation inhibitors (tyrphostins) with quite different structures(19 compounds of the bcnivlidenc maiononitrile famliy and 13 compounds of the 3-substituted indolin-2-ones family) With the aid of a pharmacophore analysis method (CATALYST). a common three-dimensional pharmacophore model to these two kinds of molecules has been discovered. A better 3D-QSAR analysis based on the generated pharmacophore model was conducted (correaate coeffcient R=0.9561 and the model shows very good predictive ability.
In the present study we investigated two groups of small molecular tyrosine kinase phosphorylation inhibitors (tyrphostins) with quite different structures(19 compounds of the bcnivlidenc maiononitrile famliy and 13 compounds of the 3-substituted indolin-2-ones family) With the aid of a pharmacophore analysis method (CATALYST). a common three-dimensional pharmacophore model to these two kinds of molecules has been discovered. A better 3D-QSAR analysis based on the generated pharmacophore model was conducted (correaate coeffcient R=0.9561 and the model shows very good predictive ability.
1999, 10(9): 759-762
Abstract:
In this study, an automated conformer selection procedure using genetic algorithm (GA) has been applied in comparative molecular field analysis (CoMPA) method. Using genetic algorithm, the 3D-QSAR model is optimized to an optimal one. From the calculation results, a group of QSAR models with high predictive ability can be obtained, which is superior than using conventional CoMFA; meamvhile, the active conlormers for these compounds in data set can he detcrmin cd from the best model.
In this study, an automated conformer selection procedure using genetic algorithm (GA) has been applied in comparative molecular field analysis (CoMPA) method. Using genetic algorithm, the 3D-QSAR model is optimized to an optimal one. From the calculation results, a group of QSAR models with high predictive ability can be obtained, which is superior than using conventional CoMFA; meamvhile, the active conlormers for these compounds in data set can he detcrmin cd from the best model.
1999, 10(9): 763-766
Abstract:
Twenty-two indole Schiff-base derivatives were synthesized. Two special ways of cleavage were discussed in the formation of the specific fragment ions in the mass spectra(MS).
Twenty-two indole Schiff-base derivatives were synthesized. Two special ways of cleavage were discussed in the formation of the specific fragment ions in the mass spectra(MS).
1999, 10(9): 767-770
Abstract:
Three new triterpenoid saponins, escins IVc (1)IVd (2) and IVf (3) were isolated from the seeds of Aesculus chinensis. They were determined as 22α-tigloyl-28-acctylprotoaescigenin-3B-0-[B-D-glucopyranosyl (1→2)] [B-D-glucopyranosyl(1→4)]-B-D-glucopyranosiduronic acid 1.22a-angeloyl-28-acetylprotoaescigenin-3B-0-[B-D-glucopyranosyl (1→2)] [B-D-glucopyrano-sy((1→4)]-B-D-glucopyranosiduronic acid 2 and 28-tigloyl protoaescigenin-3B-0-[B-D-gluco-pyranosyl(12)] [B-D-glucopyranosyl(1→4)]-B-D-glucopyranosiduronic acid 3.
Three new triterpenoid saponins, escins IVc (1)IVd (2) and IVf (3) were isolated from the seeds of Aesculus chinensis. They were determined as 22α-tigloyl-28-acctylprotoaescigenin-3B-0-[B-D-glucopyranosyl (1→2)] [B-D-glucopyranosyl(1→4)]-B-D-glucopyranosiduronic acid 1.22a-angeloyl-28-acetylprotoaescigenin-3B-0-[B-D-glucopyranosyl (1→2)] [B-D-glucopyrano-sy((1→4)]-B-D-glucopyranosiduronic acid 2 and 28-tigloyl protoaescigenin-3B-0-[B-D-gluco-pyranosyl(12)] [B-D-glucopyranosyl(1→4)]-B-D-glucopyranosiduronic acid 3.
1999, 10(9): 771-774
Abstract:
A new monotcrpcne glycoside named paeonivayin with other seven known compounds were isolated from the routs of Paeortio delavcrvi branch. and their structures were determined by means of spectroscopic studies
A new monotcrpcne glycoside named paeonivayin with other seven known compounds were isolated from the routs of Paeortio delavcrvi branch. and their structures were determined by means of spectroscopic studies
1999, 10(9): 775-776
Abstract:
A new resveratrol trimer, amurensin G (1). was isolated from the roots of Vitis anznrensvs Rupr. Its structure and relative configuration were established on the basis of spectral evidence, especially on HMBC spectrum and NUT difference experiments.
A new resveratrol trimer, amurensin G (1). was isolated from the roots of Vitis anznrensvs Rupr. Its structure and relative configuration were established on the basis of spectral evidence, especially on HMBC spectrum and NUT difference experiments.
1999, 10(9): 777-780
Abstract:
Separation of basic proteins was performed using a homemade field-modulated capillary electrophoresis system. The resolution, elution and even wall adsorption can be regulated by adjusting the radial rather than axial voltage applied. Selection of running buffer and pH was found to be critical.
Separation of basic proteins was performed using a homemade field-modulated capillary electrophoresis system. The resolution, elution and even wall adsorption can be regulated by adjusting the radial rather than axial voltage applied. Selection of running buffer and pH was found to be critical.
1999, 10(9): 781-782
Abstract:
Electrochemical voltammctric method can be used to monitor cell health state during its growth. Here we studied the effect of caffeic acid on leukemia cells U937 by the voltammetric behavior of the cells. The result showed that this drug had a negative influence on cell health which suggests that caflcic acid may be used in inhibition oftumor cells
Electrochemical voltammctric method can be used to monitor cell health state during its growth. Here we studied the effect of caffeic acid on leukemia cells U937 by the voltammetric behavior of the cells. The result showed that this drug had a negative influence on cell health which suggests that caflcic acid may be used in inhibition oftumor cells
1999, 10(9): 783-786
Abstract:
The synthesis and characterization of meso-tetra (4-n-lauroyloxy phenyl) porphyrin with long ester chains are reported. The domains of stability and the structure of the liquid crystalline phases are determined by optical microscopy and differential scanning calorimerials (DSC).
The synthesis and characterization of meso-tetra (4-n-lauroyloxy phenyl) porphyrin with long ester chains are reported. The domains of stability and the structure of the liquid crystalline phases are determined by optical microscopy and differential scanning calorimerials (DSC).
1999, 10(9): 787-788
Abstract:
The copolymer of N-4-dibenzoylmethat}e maleimide (p-DBM1) with styrene (St) was prepared and characterized by gel permeation chromatography, thermal analysis and spectroscopy.
The copolymer of N-4-dibenzoylmethat}e maleimide (p-DBM1) with styrene (St) was prepared and characterized by gel permeation chromatography, thermal analysis and spectroscopy.
1999, 10(9): 789-792
Abstract:
1-O-aminoacyl-3-O-alkyl acyl glycerols were synthesized by lipases in good yields and their surfactant properties were explored.
1-O-aminoacyl-3-O-alkyl acyl glycerols were synthesized by lipases in good yields and their surfactant properties were explored.
1999, 10(9): 793-794
Abstract:
Silver phenylacetylide oligomer was found to exhibit prominent third-orde,nonlinear optical property. with susceptibility χ(3) of 2.4×10-4 esu (10-14 mol/L in 1:1 dimethyl sulfoxide/CHCl3 mixed solution) and second-order hyperpolarizability γ of 5.18×10-32 esu via heterodyned ultrafast optical Kerr et}feet measurement. It existed mainly as 1:1 complex oligomers and polymers as characterized by mass spectroscopy and elemental analysis etc.
Silver phenylacetylide oligomer was found to exhibit prominent third-orde,nonlinear optical property. with susceptibility χ(3) of 2.4×10-4 esu (10-14 mol/L in 1:1 dimethyl sulfoxide/CHCl3 mixed solution) and second-order hyperpolarizability γ of 5.18×10-32 esu via heterodyned ultrafast optical Kerr et}feet measurement. It existed mainly as 1:1 complex oligomers and polymers as characterized by mass spectroscopy and elemental analysis etc.
1999, 10(9): 795-798
Abstract:
The fluorescence of polystyrene labeled with pyrenyl groups has been investigated in concentrated solutions.The ratio of excimer to monomer intensities (lc/1m) of pyrenyl labets is Found to vary with inereasing polymer concentration (C) and display fractional dependence on the C. A critical concentration, Cm at about 0.32g/ml, is first manifested. The results arc interpreted by interchain interaction and entanglement of polymer chains.
The fluorescence of polystyrene labeled with pyrenyl groups has been investigated in concentrated solutions.The ratio of excimer to monomer intensities (lc/1m) of pyrenyl labets is Found to vary with inereasing polymer concentration (C) and display fractional dependence on the C. A critical concentration, Cm at about 0.32g/ml, is first manifested. The results arc interpreted by interchain interaction and entanglement of polymer chains.
1999, 10(9): 799-802
Abstract:
A new type of phosphor Sr2ZrO2 with one-dimensional structure was prepared by solid reaction and its luminescence is seen at room temperature. The excitation and emission spectra were measured and display broad maximum at 354 nm and 368 nm respectively. The mechanism of this luminescence is ascribed to charge transfer.
A new type of phosphor Sr2ZrO2 with one-dimensional structure was prepared by solid reaction and its luminescence is seen at room temperature. The excitation and emission spectra were measured and display broad maximum at 354 nm and 368 nm respectively. The mechanism of this luminescence is ascribed to charge transfer.
1999, 10(9): 803-806
Abstract:
A new preparation method was proposed to deposit amorphous alloys containing NiP and metallic additives such as Fe, Co. and Cu. The different effects of metallic additive on structure and catalytic properties of supported amorphous NiMPB/Si02 (M=Fe, Co. Cu) catalysts were observed. and the improvement of catalytic activity due to heating pretreatment in hydrogen was found.
A new preparation method was proposed to deposit amorphous alloys containing NiP and metallic additives such as Fe, Co. and Cu. The different effects of metallic additive on structure and catalytic properties of supported amorphous NiMPB/Si02 (M=Fe, Co. Cu) catalysts were observed. and the improvement of catalytic activity due to heating pretreatment in hydrogen was found.
1999, 10(9): 807-810
Abstract:
Nanosized ZnS doped with different concentrations of Eu3+ were prepared and analyzed by x-ray diffraction technique. The experimental results show that ZnS belongs to the cubic structure. From the photoluminescence (PL) emission spectra, it can be seen that the ratio of the emission intensity of Eu3+ at 616 nm to that at 590 nm increases as the increasing of Eu3+. This phenomenon reveals that the site symmetry of Eu3+ reduces as the increasing of Eu3+.
Nanosized ZnS doped with different concentrations of Eu3+ were prepared and analyzed by x-ray diffraction technique. The experimental results show that ZnS belongs to the cubic structure. From the photoluminescence (PL) emission spectra, it can be seen that the ratio of the emission intensity of Eu3+ at 616 nm to that at 590 nm increases as the increasing of Eu3+. This phenomenon reveals that the site symmetry of Eu3+ reduces as the increasing of Eu3+.
