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1998 Volume 9 Issue 10
1998, 9(10): 885-887
Abstract:
The Se-Si bond in arylselenotrimethylsilane was reduced by samarium diiodide to produce samarium arylselenolate, which reacted with α,β-unsaturated esters or α,β-unsaturated nitriles to give β-selenoesters and β-selenonitriles, respectively.
The Se-Si bond in arylselenotrimethylsilane was reduced by samarium diiodide to produce samarium arylselenolate, which reacted with α,β-unsaturated esters or α,β-unsaturated nitriles to give β-selenoesters and β-selenonitriles, respectively.
1998, 9(10): 889-892
Abstract:
Substituted PhMgX and PhTi (OCHMe2)4MgX react with 3,5-O-isopropylidene-L-glucurono-γ-lactone 4 to give tetraols 5a~e and its stereoisomers 6a~e. Tetraols 5a~e are the important intermediates in the synthesis of howiinol A1 and its derivatives. The stereoselectivities of substituted PhTi (OCHMe2)4Mg (5a~e:6a~e ratio, 68~72:32~28) were better than those of substituted PhMgX (33~64:67~36) in the reaction. The effects of different substituted groups and positions (p-Me, m-Me, o-MeO, p-Cl) of the phenyl ring on their stereoselectivies were not significant.
Substituted PhMgX and PhTi (OCHMe2)4MgX react with 3,5-O-isopropylidene-L-glucurono-γ-lactone 4 to give tetraols 5a~e and its stereoisomers 6a~e. Tetraols 5a~e are the important intermediates in the synthesis of howiinol A1 and its derivatives. The stereoselectivities of substituted PhTi (OCHMe2)4Mg (5a~e:6a~e ratio, 68~72:32~28) were better than those of substituted PhMgX (33~64:67~36) in the reaction. The effects of different substituted groups and positions (p-Me, m-Me, o-MeO, p-Cl) of the phenyl ring on their stereoselectivies were not significant.
1998, 9(10): 893-894
Abstract:
The synthesis of a new aryl ether ketone polymer with an advantageous ratio of glass transition temperature to melting temperature is reported.
The synthesis of a new aryl ether ketone polymer with an advantageous ratio of glass transition temperature to melting temperature is reported.
1998, 9(10): 895-896
Abstract:
In Me2SO, an X-philic reaction took place between α-cyanobenzyl carbanion and CCl4. The intermediate dichlorocarbene was trapped by the primary product dicyanostilbene to give the alkene-carbene adduct, 1,l-dichloro-2,3-dicyano-2,3-diphenylcyclopropane.
In Me2SO, an X-philic reaction took place between α-cyanobenzyl carbanion and CCl4. The intermediate dichlorocarbene was trapped by the primary product dicyanostilbene to give the alkene-carbene adduct, 1,l-dichloro-2,3-dicyano-2,3-diphenylcyclopropane.
1998, 9(10): 897-898
Abstract:
Eight Te-substituted di-n-butyltellurium bromides were synthesized. Their equilibrium acidities (pKA) were determined in DMSO at 25℃ and the thermodynamic stabilities of the corresponding tellurium ylide carbanions were accordingly discussed.
Eight Te-substituted di-n-butyltellurium bromides were synthesized. Their equilibrium acidities (pKA) were determined in DMSO at 25℃ and the thermodynamic stabilities of the corresponding tellurium ylide carbanions were accordingly discussed.
1998, 9(10): 899-902
Abstract:
3-Methoxy-,3, 5-dimethoxy-, and 3-pheny 1-4-hydroxyacetophenones suffered alkyl carbonyl C-C bond scission to yield 4-hydroxybenzoate esters and 4-isopropenylphenols under standard conditions of ethylene ketal formation; the latter underwent in situ dimerization, cyclization, and rearrangement to give substituted indanols. The isopropenylphenol derived from 3,5-ditertbuty 1-4-hydroxyacetophenone did not dimerize but condensed with its precursor to yield a substituted diphenylpropanone. 3-nitro-, 3,5-dinitro-, and 3,5-dibromo-4-hydroxyacetophenones on the other hand reacted normally to give ethylene ketals in good yields.
3-Methoxy-,3, 5-dimethoxy-, and 3-pheny 1-4-hydroxyacetophenones suffered alkyl carbonyl C-C bond scission to yield 4-hydroxybenzoate esters and 4-isopropenylphenols under standard conditions of ethylene ketal formation; the latter underwent in situ dimerization, cyclization, and rearrangement to give substituted indanols. The isopropenylphenol derived from 3,5-ditertbuty 1-4-hydroxyacetophenone did not dimerize but condensed with its precursor to yield a substituted diphenylpropanone. 3-nitro-, 3,5-dinitro-, and 3,5-dibromo-4-hydroxyacetophenones on the other hand reacted normally to give ethylene ketals in good yields.
1998, 9(10): 903-905
Abstract:
The isomerization/chlorination of 0,0-diallyl thiophosphoric(-nic) acid esters with phosphrus oxychloride gives S-allyl thiophosphoro(-no)chloride, which reacts with substituted phenol in chloroform in the presence of triethylamine to afford eighteen new S-allyl thiophosphoric(-nic) acid derivatives. Thus, a new convenient method has been provided for synthesis of the title compounds.
The isomerization/chlorination of 0,0-diallyl thiophosphoric(-nic) acid esters with phosphrus oxychloride gives S-allyl thiophosphoro(-no)chloride, which reacts with substituted phenol in chloroform in the presence of triethylamine to afford eighteen new S-allyl thiophosphoric(-nic) acid derivatives. Thus, a new convenient method has been provided for synthesis of the title compounds.
1998, 9(10): 907-910
Abstract:
New optically active bicyclic compounds containing a fluorine atom (3a and 3b) were prepared from the reaction of Garner aldehyde 1 with DAST.
New optically active bicyclic compounds containing a fluorine atom (3a and 3b) were prepared from the reaction of Garner aldehyde 1 with DAST.
1998, 9(10): 911-912
Abstract:
The Eu3+-doped Na24P2W22O83 has been prepared by solid state reaction, and characterized by element analysis, infrared spectroscopy, powder X-ray diffractometry. The emission and excitation spectra were measured. The luminescence properties of Eu3+-doped Na24P2W22O83 and the energy transfer mechanism were discussed.
The Eu3+-doped Na24P2W22O83 has been prepared by solid state reaction, and characterized by element analysis, infrared spectroscopy, powder X-ray diffractometry. The emission and excitation spectra were measured. The luminescence properties of Eu3+-doped Na24P2W22O83 and the energy transfer mechanism were discussed.
1998, 9(10): 913-916
Abstract:
Two squarylium cyanine dyes (Sqs) were synthesized to explore their applications in photoelectrochemical solar cells. Nanocrystalline Ti02 electrodes modified with Sqs have been prepared to probe the photosensitization effects. A rather high photoelectric conversion efficiency of up to 2.17% and the top incident monochromatic photon-to-photocurrent conversion efficiency (IPCE) of 6.2% at 650nm were obtained from the Sq2-modified nanocrystalline Ti02 electrode.
Two squarylium cyanine dyes (Sqs) were synthesized to explore their applications in photoelectrochemical solar cells. Nanocrystalline Ti02 electrodes modified with Sqs have been prepared to probe the photosensitization effects. A rather high photoelectric conversion efficiency of up to 2.17% and the top incident monochromatic photon-to-photocurrent conversion efficiency (IPCE) of 6.2% at 650nm were obtained from the Sq2-modified nanocrystalline Ti02 electrode.
1998, 9(10): 917-918
Abstract:
A new efficient synthesis of bisphenol A diether bis-imidazoles and bis-benzimidazoles by bromoalkylation and imidazolylation or benzimidazolylation two-step reactions from commercial bisphenol A, imidazole, 2-methylimidazole and benzimidazole is reported.
A new efficient synthesis of bisphenol A diether bis-imidazoles and bis-benzimidazoles by bromoalkylation and imidazolylation or benzimidazolylation two-step reactions from commercial bisphenol A, imidazole, 2-methylimidazole and benzimidazole is reported.
1998, 9(10): 919-922
Abstract:
This paper reports the primary results of the study on p-lactam derivatives of 2,4-diaryl-2,3-dihydro-l,5-benzothiazepines. Five title compounds have been synthesized, and their configuration and conformation were determined by X-ray crystailographic analysis.
This paper reports the primary results of the study on p-lactam derivatives of 2,4-diaryl-2,3-dihydro-l,5-benzothiazepines. Five title compounds have been synthesized, and their configuration and conformation were determined by X-ray crystailographic analysis.
1998, 9(10): 923-926
Abstract:
The synthesis and characterization of the first example of lower-rim-connected double-calix [6]arene are reported, in which a 1,2,4-triply bridged calix [6]arene subunit is connected to a calix [6]arene subunit via a polyether chain.
The synthesis and characterization of the first example of lower-rim-connected double-calix [6]arene are reported, in which a 1,2,4-triply bridged calix [6]arene subunit is connected to a calix [6]arene subunit via a polyether chain.
1998, 9(10): 927-928
Abstract:
The macrolide alkaloid euonine 1 with pharmacologic activity was prepared from the alkaloid wilforgine 2. Their structures were confirmed by IR, NMR, MS and optical rotation.
The macrolide alkaloid euonine 1 with pharmacologic activity was prepared from the alkaloid wilforgine 2. Their structures were confirmed by IR, NMR, MS and optical rotation.
1998, 9(10): 929-930
Abstract:
Chrysanthemol, an active antiinflammatory sesquiterpene from Chrysanthemum indicum L., was synthesized in ten steps from R-(+)-carvone with an overall yield of 2.4%. The analytic data of the synthetic target compound was identical with that of natural chrysanthemol.
Chrysanthemol, an active antiinflammatory sesquiterpene from Chrysanthemum indicum L., was synthesized in ten steps from R-(+)-carvone with an overall yield of 2.4%. The analytic data of the synthetic target compound was identical with that of natural chrysanthemol.
1998, 9(10): 931-934
Abstract:
Both enantiomers R-l and S-l of a chiral C60 derivative were synthesized by the reactions of C60 with 1, l'-bi-2-naphthol bis(azidoacetates) and characterized by FD-MS, FT-IR, 1H NMR, 13C NMR, UV-VIS, CD spectra.
Both enantiomers R-l and S-l of a chiral C60 derivative were synthesized by the reactions of C60 with 1, l'-bi-2-naphthol bis(azidoacetates) and characterized by FD-MS, FT-IR, 1H NMR, 13C NMR, UV-VIS, CD spectra.
1998, 9(10): 935-938
Abstract:
Two new polyoxygenated cyclohexenes, named uvacaloIA (l), and B (2) were isolated from the rhizomes of Uvaria calamistrata. On the basis of spectral analysis and chemical derivatization, including preparation of Mosher esters, the structure of 1 to 2 were established.
Two new polyoxygenated cyclohexenes, named uvacaloIA (l), and B (2) were isolated from the rhizomes of Uvaria calamistrata. On the basis of spectral analysis and chemical derivatization, including preparation of Mosher esters, the structure of 1 to 2 were established.
1998, 9(10): 939-940
Abstract:
A new sesquiterpene, 12,13-di-acetoxyl-1,4,6,11-eudesmanetetrol 1, was isolated from Michelia yunnanensis. The structure was elucidated on the basis of spectral data.
A new sesquiterpene, 12,13-di-acetoxyl-1,4,6,11-eudesmanetetrol 1, was isolated from Michelia yunnanensis. The structure was elucidated on the basis of spectral data.
1998, 9(10): 941-944
Abstract:
A simple, rapid and accurate capillary zone electrophoresis method was developed for the determination of chlorogenic acid as a marker in traditional Chinese medicines. The buffer solution comprised of 10 mmol/L sodium phosphate and 20 mmol/L boric acid containing 5% ethanol with the pH value adjusted to 7.00. The contents of chlorogenic acid in Flos Lonicerae and Flos Lonicerae containing herbal preparations were determined within 15 min.
A simple, rapid and accurate capillary zone electrophoresis method was developed for the determination of chlorogenic acid as a marker in traditional Chinese medicines. The buffer solution comprised of 10 mmol/L sodium phosphate and 20 mmol/L boric acid containing 5% ethanol with the pH value adjusted to 7.00. The contents of chlorogenic acid in Flos Lonicerae and Flos Lonicerae containing herbal preparations were determined within 15 min.
1998, 9(10): 945-948
Abstract:
The effect of Cl- ion on the anodic iron dissolution in H2SO4 solutions containing H2S has been studied by using electrochemical polarization curve measurements. The competitive adsorption for Cl- and HS- ions at an anodic potential has been calculated using the CNDO/2 method. The results show that a certain concentration of the Cl- ion can be adsorbed steadily and inhibit the anodic reaction of iron catalyzed by HS-. However, when the Cl- ion reaches the saturation adsorption, it begins to promote the anodic reaction of iron due to the increased negative charge of iron atoms.
The effect of Cl- ion on the anodic iron dissolution in H2SO4 solutions containing H2S has been studied by using electrochemical polarization curve measurements. The competitive adsorption for Cl- and HS- ions at an anodic potential has been calculated using the CNDO/2 method. The results show that a certain concentration of the Cl- ion can be adsorbed steadily and inhibit the anodic reaction of iron catalyzed by HS-. However, when the Cl- ion reaches the saturation adsorption, it begins to promote the anodic reaction of iron due to the increased negative charge of iron atoms.
1998, 9(10): 949-951
Abstract:
A novel and very sensitive electroanalytical method, based on the adsorption chronopotentiometry in the presence of cupferron,was developed for the determination of trace levels of aluminum. The working linear range is 2×lO-9-9×lO-7 mol/L and the detection limit is 1×1O-9 mol/L. It has been successfully applied to the determination of A1 in various drinking-water samples.
A novel and very sensitive electroanalytical method, based on the adsorption chronopotentiometry in the presence of cupferron,was developed for the determination of trace levels of aluminum. The working linear range is 2×lO-9-9×lO-7 mol/L and the detection limit is 1×1O-9 mol/L. It has been successfully applied to the determination of A1 in various drinking-water samples.
1998, 9(10): 953-955
Abstract:
The active intermediates of hexacoordinated 4-nitrotrispirophosphoric amino acid (P(6)-AA), which were formed by the reaction of 4-nitro-0,0-phenylene phosphochloridate (NO-PPC) with silanizing serine, threonine and cysteine, were observed by 31P NMR spectra. The reaction mechanism of these processes was discussed. In addition, some interesting results were observed by mixing 4-nitro-2,2,2-tricloro-l,3, 2-benzodioxaphosph(v)ole (NTB) with silanizing serine and histidine.
The active intermediates of hexacoordinated 4-nitrotrispirophosphoric amino acid (P(6)-AA), which were formed by the reaction of 4-nitro-0,0-phenylene phosphochloridate (NO-PPC) with silanizing serine, threonine and cysteine, were observed by 31P NMR spectra. The reaction mechanism of these processes was discussed. In addition, some interesting results were observed by mixing 4-nitro-2,2,2-tricloro-l,3, 2-benzodioxaphosph(v)ole (NTB) with silanizing serine and histidine.
1998, 9(10): 957-959
Abstract:
Further investigation of the metabolites of orally administered icariin in rats was made. Two minor metabolites, icariside I and icariside Ⅱ, were identified in gastric content, and two metabolites, icariside Ⅱ and icaritin, in intestinal content. The major metabolic route of icariin was proposed.
Further investigation of the metabolites of orally administered icariin in rats was made. Two minor metabolites, icariside I and icariside Ⅱ, were identified in gastric content, and two metabolites, icariside Ⅱ and icaritin, in intestinal content. The major metabolic route of icariin was proposed.
1998, 9(10): 961-964
Abstract:
The mechanism of ionization and fragmentation for terphenyl (diphenylbenzene) with three structural ring isomers (ortho-, meta-and para-), and stilbene (1,2-diphenylethylene) with two geometrical isomers (trans-and cis-) by EI mass spectrometry and ionization efficiency curves are investigation.
The mechanism of ionization and fragmentation for terphenyl (diphenylbenzene) with three structural ring isomers (ortho-, meta-and para-), and stilbene (1,2-diphenylethylene) with two geometrical isomers (trans-and cis-) by EI mass spectrometry and ionization efficiency curves are investigation.
1998, 9(10): 965-966
Abstract:
Recovery behavior of uniaxially stretched amorphous poly (ethylene terephthalate) (a-PET) film near glass transition temperature (Tg) was studied. A strain recovery curve showed that the recovery was made up of two components each with different relaxation time.
Recovery behavior of uniaxially stretched amorphous poly (ethylene terephthalate) (a-PET) film near glass transition temperature (Tg) was studied. A strain recovery curve showed that the recovery was made up of two components each with different relaxation time.
1998, 9(10): 967-970
Abstract:
Amphiphilic complexes of N-octadecyl-8-hydroxy-2-quinoline carboxamide, M (O-Q)2, form stable monolayer on pure water subphase and can be easily fabricated as highly ordered and uniform LB films, which were characterized by absorption spectra and low-angle X-ray diffraction measurements.
Amphiphilic complexes of N-octadecyl-8-hydroxy-2-quinoline carboxamide, M (O-Q)2, form stable monolayer on pure water subphase and can be easily fabricated as highly ordered and uniform LB films, which were characterized by absorption spectra and low-angle X-ray diffraction measurements.
1998, 9(10): 971-972
Abstract:
X-ray crystal structures of 2,2',3,3'-and 3,3',4,4-biphenyltetracarboxylic dianhydride (2,2',3,3'-and 3,3',4,4'-BPDA) were determined. The dianhydride isomers have different symmetry caused by difference in two anhydride group positions and the dihedral angles between the two phenyl rings are 62.9°for 2,2',3,3',-BPDA and 0°for 3,3',4,4'-BPDA respectively. The polyimides from 2,2',3,3'-BPDA exhibit enhanced solubility, higher thermal stability, and higher glass transition temperature (Tg) compared with those from 3,3',4,4'-BPDA.
X-ray crystal structures of 2,2',3,3'-and 3,3',4,4-biphenyltetracarboxylic dianhydride (2,2',3,3'-and 3,3',4,4'-BPDA) were determined. The dianhydride isomers have different symmetry caused by difference in two anhydride group positions and the dihedral angles between the two phenyl rings are 62.9°for 2,2',3,3',-BPDA and 0°for 3,3',4,4'-BPDA respectively. The polyimides from 2,2',3,3'-BPDA exhibit enhanced solubility, higher thermal stability, and higher glass transition temperature (Tg) compared with those from 3,3',4,4'-BPDA.
1998, 9(10): 973-975
Abstract:
Two new carbonyl manganese compounds were obtained by reactions of 2.6-di (bi-phenylphosphine) pyridine (PNP) with CpMn(CO)3.The structures of the compounds were confirmed by elemental analysis, IR,1H NMR and 31P NMR. The results showed that the mixed-donor ligand (PNP) was coordinated to manganese only through the phosphorus atom.
Two new carbonyl manganese compounds were obtained by reactions of 2.6-di (bi-phenylphosphine) pyridine (PNP) with CpMn(CO)3.The structures of the compounds were confirmed by elemental analysis, IR,1H NMR and 31P NMR. The results showed that the mixed-donor ligand (PNP) was coordinated to manganese only through the phosphorus atom.
Synthesis and Crystsl Structure of a Novel Mercapto-organotin Complex:[Et3NH] [Ph2SnCl(μ2-SCH2COO-)]
1998, 9(10): 977-978
Abstract:
A novel complex [Et3NH] [Ph2SnCl(μ2-SCH2COO-)] has been unexpectedly obtained by the reaction of Ph3SnCl and HSCH2COOH in 2:1 molar ratio in the presence of organic base Et3N. Possible dephenylation mechanism was illustrated. The X-ray diffraction study has shown that the title complex consists of cation moiety [Et3NH] and anion moiety [Ph2SnCl(μ2-SCH2COO-)]with tin(IV) in a trigonal bipyramidal coordination geometry.
A novel complex [Et3NH] [Ph2SnCl(μ2-SCH2COO-)] has been unexpectedly obtained by the reaction of Ph3SnCl and HSCH2COOH in 2:1 molar ratio in the presence of organic base Et3N. Possible dephenylation mechanism was illustrated. The X-ray diffraction study has shown that the title complex consists of cation moiety [Et3NH] and anion moiety [Ph2SnCl(μ2-SCH2COO-)]with tin(IV) in a trigonal bipyramidal coordination geometry.
