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1992 Volume 3 Issue 5
1992, 3(5): 329-332
Abstract:
Heteroatom-directed aromatic lithiation reactions usedfor the regiospecific synthesis of o-isopropyl substituted phenolic andbenzyl alcoholic compounds are described
Heteroatom-directed aromatic lithiation reactions usedfor the regiospecific synthesis of o-isopropyl substituted phenolic andbenzyl alcoholic compounds are described
1992, 3(5): 333-334
Abstract:
Plumbagic acid[β-(2, 3-dihydroxybenzoyl)butyric acid](1), hasbeen synthesized from commcrcially available catechol by two facile routeswith overall yields of 18.6% and 53.5%, rcspectively
Plumbagic acid[β-(2, 3-dihydroxybenzoyl)butyric acid](1), hasbeen synthesized from commcrcially available catechol by two facile routeswith overall yields of 18.6% and 53.5%, rcspectively
1992, 3(5): 335-336
Abstract:
The double oxidative coupling of methyl 8-bromo-3, 4-dihydro-xy-5, 7-dimethoxy-2-naphthylacetate and its solvent effect are studied.Demethylation followed by methylation or vice versa of dimethyl-2, 11-dihy-droxy-4, 6, 7, 9-tetramethoxy-3, 10-perylenequinone-1, 12-diacetate can beeffected regioselectively and amenable to natural product synthesis
The double oxidative coupling of methyl 8-bromo-3, 4-dihydro-xy-5, 7-dimethoxy-2-naphthylacetate and its solvent effect are studied.Demethylation followed by methylation or vice versa of dimethyl-2, 11-dihy-droxy-4, 6, 7, 9-tetramethoxy-3, 10-perylenequinone-1, 12-diacetate can beeffected regioselectively and amenable to natural product synthesis
1992, 3(5): 337-338
Abstract:
The acylation of 3-pentanone enamine was studied and a novelformation of 4-pyrones from <β-diketone enol esters was found involvingan intramolecular O-to C-acyl shift followed by cyclization
The acylation of 3-pentanone enamine was studied and a novelformation of 4-pyrones from <β-diketone enol esters was found involvingan intramolecular O-to C-acyl shift followed by cyclization
1992, 3(5): 339-340
Abstract:
New methods for dehydrogenation of steroidal 2, 5(10)-dienes with2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ) or pyridinium hydrobromideperbromide(PHP, Py·HBr·Br2) to aromatic A ring steroid in quantitative yield inshort time are described
New methods for dehydrogenation of steroidal 2, 5(10)-dienes with2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ) or pyridinium hydrobromideperbromide(PHP, Py·HBr·Br2) to aromatic A ring steroid in quantitative yield inshort time are described
1992, 3(5): 341-342
Abstract:
Reaction of glycine with phosphorus trichloride in presence of triethylamine hasurnished the ovel spirohydridophosphorane.Its structure has been characterized by elementalanalysis, n.m.r.spectra and mass spectrum.The compound reacted with phenylisothiocyanate togive 2-phenyliminothiazolid-5-one
Reaction of glycine with phosphorus trichloride in presence of triethylamine hasurnished the ovel spirohydridophosphorane.Its structure has been characterized by elementalanalysis, n.m.r.spectra and mass spectrum.The compound reacted with phenylisothiocyanate togive 2-phenyliminothiazolid-5-one
1992, 3(5): 343-346
Abstract:
The β-carboxylic group plays an important role inthe peptide formation, esterification and the ester exchangeat the phosphoryl group of N-phosphorylated aspartic acid
The β-carboxylic group plays an important role inthe peptide formation, esterification and the ester exchangeat the phosphoryl group of N-phosphorylated aspartic acid
1992, 3(5): 347-348
Abstract:
Two series of new compounds:the aliphatic acylaminoethyl glycines (Ⅰ) and their cyclo-condensationproducts-allphatic acylaminoethyl plperazlnones (Ⅱ) were synthesized.The results of bactericidal and bacteriostatictests show that the two series of compounds are good bactericldal agents
Two series of new compounds:the aliphatic acylaminoethyl glycines (Ⅰ) and their cyclo-condensationproducts-allphatic acylaminoethyl plperazlnones (Ⅱ) were synthesized.The results of bactericidal and bacteriostatictests show that the two series of compounds are good bactericldal agents
1992, 3(5): 349-350
Abstract:
Synthesis and surface active properties of the oxyethylenated fatty alcohol 2-hydroxypropyl sulfonates wereinvestigated.Of all surface active compounds studied, those with a 2-hydroxypropyl (HP) moiety in the moleculeare more surface-active than the corresponding compounds without
Synthesis and surface active properties of the oxyethylenated fatty alcohol 2-hydroxypropyl sulfonates wereinvestigated.Of all surface active compounds studied, those with a 2-hydroxypropyl (HP) moiety in the moleculeare more surface-active than the corresponding compounds without
1992, 3(5): 351-354
Abstract:
Carbonylation of allyl halides catalyzed by poly(N-vinyl-2-pyrro-lidone) anchored palladium catalyst affords β, r-butonic acid under atmo-spheric pressure and at room temperature.The activity and efficiency ofthe catalyst are much higher than those of the reported catalysts for thisreaction
Carbonylation of allyl halides catalyzed by poly(N-vinyl-2-pyrro-lidone) anchored palladium catalyst affords β, r-butonic acid under atmo-spheric pressure and at room temperature.The activity and efficiency ofthe catalyst are much higher than those of the reported catalysts for thisreaction
1992, 3(5): 355-356
Abstract:
The effects of peptides, amino acids and organic bases as an axial ligand on reaction ac-tivities in the electrocarboxylation of benzyl chloride with CO2 catalyzed by CoTPP are reported.The imidazole organic base, peptide containing —SH and amino acid containing imidazolyl en-hance the catalytic activity.The effect of imidazole amounts on the catalytic activity of CoTPP isstudied
The effects of peptides, amino acids and organic bases as an axial ligand on reaction ac-tivities in the electrocarboxylation of benzyl chloride with CO2 catalyzed by CoTPP are reported.The imidazole organic base, peptide containing —SH and amino acid containing imidazolyl en-hance the catalytic activity.The effect of imidazole amounts on the catalytic activity of CoTPP isstudied
1992, 3(5): 357-358
Abstract:
The effects of various factors on the electrocarboxylation of organic compounds withcarbon dioxide catalyzed by metalloporphyrin are studied.The optimal potential of electrocar-boxylation is-1.6 V(vs.SCE).A weak protic solvent methanol can enhance catalytic activity.Tetrabutylammonium iodide is the best one of five electrolytes.The yields and current efficienciesof electrocarboxylation are increased slowly as the concentration of catalyst increases
The effects of various factors on the electrocarboxylation of organic compounds withcarbon dioxide catalyzed by metalloporphyrin are studied.The optimal potential of electrocar-boxylation is-1.6 V(vs.SCE).A weak protic solvent methanol can enhance catalytic activity.Tetrabutylammonium iodide is the best one of five electrolytes.The yields and current efficienciesof electrocarboxylation are increased slowly as the concentration of catalyst increases
1992, 3(5): 359-360
Abstract:
Teroolymerization of enichlorohydrin(ECH)-maleic anhydride(MAn)-carbon dioxide(CO2) was carried out by using Y(P204)3-Al(i-Bu)3 as catalyst for the first time.The terpolymersobtained were characterized by IR and 1H-NMR.It was foundthat the composition of the teroolymer was influenced by theaddition mode, initial monomer charge ratio, etc
Teroolymerization of enichlorohydrin(ECH)-maleic anhydride(MAn)-carbon dioxide(CO2) was carried out by using Y(P204)3-Al(i-Bu)3 as catalyst for the first time.The terpolymersobtained were characterized by IR and 1H-NMR.It was foundthat the composition of the teroolymer was influenced by theaddition mode, initial monomer charge ratio, etc
1992, 3(5): 361-362
Abstract:
An unusual rearrangement by contraction of the ring C in denudatine 1 and di-acetyldenudatine 2 is presented
An unusual rearrangement by contraction of the ring C in denudatine 1 and di-acetyldenudatine 2 is presented
1992, 3(5): 363-366
Abstract:
Aromatic bond including metallic atom (Ni) is investigated byEHMO calculation.The NMR spectra and the mechanism for hydrolysis arediscussed on the ground of results of computation
Aromatic bond including metallic atom (Ni) is investigated byEHMO calculation.The NMR spectra and the mechanism for hydrolysis arediscussed on the ground of results of computation
1992, 3(5): 367-368
Abstract:
The cycloaddition reaction of ketene and formaldehyde, lesding to 2-oxetanone, has been studied theoretically by means of RHF/3-21G.This reactionis believed to be nonsynchronous but concerted, taking place through a twistedfour membered ring transition state.Two types of frontier orbitalinteractions are involved in this reaction.The activation barrier iscalculated to be 123.1KJ/mol (MP2/3-21G result)
The cycloaddition reaction of ketene and formaldehyde, lesding to 2-oxetanone, has been studied theoretically by means of RHF/3-21G.This reactionis believed to be nonsynchronous but concerted, taking place through a twistedfour membered ring transition state.Two types of frontier orbitalinteractions are involved in this reaction.The activation barrier iscalculated to be 123.1KJ/mol (MP2/3-21G result)
1992, 3(5): 369-372
Abstract:
The synthesis and liquid crystalline behaviour of a series ofalkyloxy biphenyls were described.These includes 4-alkyloxy-4-hydroxy biphenyls, p-alkyloxy biphenyl meth acrylytes, and thepolymer of p-ethoxy biphenyl meth acrylate (PEBPMA).The effectsof reaction conditions on the yields of products were investigated.Theliquid crystalline behaviour of the products was characterized by DSC, polarizing microscopy..It was found that the PEBPMA showedsmectic phase
The synthesis and liquid crystalline behaviour of a series ofalkyloxy biphenyls were described.These includes 4-alkyloxy-4-hydroxy biphenyls, p-alkyloxy biphenyl meth acrylytes, and thepolymer of p-ethoxy biphenyl meth acrylate (PEBPMA).The effectsof reaction conditions on the yields of products were investigated.Theliquid crystalline behaviour of the products was characterized by DSC, polarizing microscopy..It was found that the PEBPMA showedsmectic phase
1992, 3(5): 373-374
Abstract:
The interactions of lanthanoid ions with dipalmitoylphosphatidylcholine bilayer werestudied by DSC and Raman spectroscopy.The results show that the addition of lanthanoid ionscauses a considerable increase of the gel to liquid crystalline transition temperature ofphospholipid and a reduction of order of lateral packing and conformation of acyl chains in SUVs
The interactions of lanthanoid ions with dipalmitoylphosphatidylcholine bilayer werestudied by DSC and Raman spectroscopy.The results show that the addition of lanthanoid ionscauses a considerable increase of the gel to liquid crystalline transition temperature ofphospholipid and a reduction of order of lateral packing and conformation of acyl chains in SUVs
1992, 3(5): 375-376
Abstract:
The vibrational spectra of both pure DPPC liposomes and DPPC multilayers reconstituted with Ge-132are reported as a function of temperature from 290 to 330K.The results show that the addition of Ge-132results in suppression of the pretransition behavior and reduction of temperature of the main transition forreconstituted system.The results also show that the degree of rigidity of the acyl chain in the presence ofGe-132 is lower than that in pure DPPC dispersion within the investigated temperature range
The vibrational spectra of both pure DPPC liposomes and DPPC multilayers reconstituted with Ge-132are reported as a function of temperature from 290 to 330K.The results show that the addition of Ge-132results in suppression of the pretransition behavior and reduction of temperature of the main transition forreconstituted system.The results also show that the degree of rigidity of the acyl chain in the presence ofGe-132 is lower than that in pure DPPC dispersion within the investigated temperature range
1992, 3(5): 377-378
Abstract:
A novel amphiphilic porphyrin(Ⅰ) containing a long chain wassynthesized and its monolayer was prepared.The structure of LB films werecharacterized by SHG (Second Harmonic Generation) and STM (ScanningTunnelling Microscope)
A novel amphiphilic porphyrin(Ⅰ) containing a long chain wassynthesized and its monolayer was prepared.The structure of LB films werecharacterized by SHG (Second Harmonic Generation) and STM (ScanningTunnelling Microscope)
1992, 3(5): 379-382
Abstract:
Formation and decay processes of pyrene excimer in acetonitrilehave been measured by laser flash spectroscopy at 475nm, and thedependence of λ1+λ2 on the pyrene concentration has also been measured at290°K.On the basis of these measurements, six rate parameters whichdescribe the behaviour of pyrene excimer system in acetonitrile solutionhave been evaluated.At 355 nm laser light irradiation, the ΔG of thepyrene excimer formation in acetonitrile is evaluated to be-30.18kJ/mol.This value is quite different from the corresponding ΔG in cyclohexane(-16.72kJ/mol)
Formation and decay processes of pyrene excimer in acetonitrilehave been measured by laser flash spectroscopy at 475nm, and thedependence of λ1+λ2 on the pyrene concentration has also been measured at290°K.On the basis of these measurements, six rate parameters whichdescribe the behaviour of pyrene excimer system in acetonitrile solutionhave been evaluated.At 355 nm laser light irradiation, the ΔG of thepyrene excimer formation in acetonitrile is evaluated to be-30.18kJ/mol.This value is quite different from the corresponding ΔG in cyclohexane(-16.72kJ/mol)
1992, 3(5): 383-386
Abstract:
Gamma-cyclodextrin (γ-CD) was used to induce the formationof N, N-diethylaniline (DEA) exciplex in 15:85(φ=0.15)v/v EtOH-H2Obinary mixture.Measurements of the fluorescence spectra of anthracene inthe presence or absence of DEA and γ-CD show that γ-CD can form 1:1:1 host/guest-Ⅰ/guest-Ⅱ inclusion complex with anthracene and DEA
Gamma-cyclodextrin (γ-CD) was used to induce the formationof N, N-diethylaniline (DEA) exciplex in 15:85(φ=0.15)v/v EtOH-H2Obinary mixture.Measurements of the fluorescence spectra of anthracene inthe presence or absence of DEA and γ-CD show that γ-CD can form 1:1:1 host/guest-Ⅰ/guest-Ⅱ inclusion complex with anthracene and DEA
1992, 3(5): 387-388
Abstract:
A new reagent 2-QADN2, 7 has been synthesized and its electroana-lytical characteristics have been studied.The procedure of the adsorptivevoltammetric determination of copper, nickel, cohalt and cadmium was workedout
A new reagent 2-QADN2, 7 has been synthesized and its electroana-lytical characteristics have been studied.The procedure of the adsorptivevoltammetric determination of copper, nickel, cohalt and cadmium was workedout
1992, 3(5): 389-392
Abstract:
A new method called differential reciprocal oscillographic chronopotentiometrictitration is presented.It makes use of appearance or disappearance of a peak of depolarizer ondifferential reciprocal oscillogram indicating the end point of titration.This method was appliedto titration of Pb2+, Cd2+, Ni2+, Co3+, Zn2+, Ga3+ and Cu2+by EDTA or EGTA.The end point oftitration is very easy to observe and the sensibility of the method is higher than that ofdiffcrcntial oscillographic chronopotcntiometric titration
A new method called differential reciprocal oscillographic chronopotentiometrictitration is presented.It makes use of appearance or disappearance of a peak of depolarizer ondifferential reciprocal oscillogram indicating the end point of titration.This method was appliedto titration of Pb2+, Cd2+, Ni2+, Co3+, Zn2+, Ga3+ and Cu2+by EDTA or EGTA.The end point oftitration is very easy to observe and the sensibility of the method is higher than that ofdiffcrcntial oscillographic chronopotcntiometric titration
1992, 3(5): 393-396
Abstract:
Cobalt-protein complexes play an important role in biochemical processes.The structure of themodel molecule, Co(H2O)3SO4(phen) has been studied by molecular mechanics.The molecular forcefield (MM2) parameters have been developed for the particular class of the complexes
Cobalt-protein complexes play an important role in biochemical processes.The structure of themodel molecule, Co(H2O)3SO4(phen) has been studied by molecular mechanics.The molecular forcefield (MM2) parameters have been developed for the particular class of the complexes
1992, 3(5): 397-398
Abstract:
[Zn(POM)2Br2](POM is 3-Methyl-4-Nitropyridine-1-Oxide), C12H12Br2N4O6Zn, Mr=533.44, triclinic, P1, a=11.450(3), b=13.027(2), c=6.605(1)Å, α=101.25(1), β=96.96(2), γ=108.06(2)°, V=901.2(4)Å3, Z=2, Dc=1.97g·cm-3, (MoKα)=0.71069Å, F(000)=520, μ=58.21cm-1, final R=0.040 for 2192 observed reflections, T=296K.The compound is amononuclear complex, containing a tetrahedrally coordinated zinc atom
[Zn(POM)2Br2](POM is 3-Methyl-4-Nitropyridine-1-Oxide), C12H12Br2N4O6Zn, Mr=533.44, triclinic, P1, a=11.450(3), b=13.027(2), c=6.605(1)Å, α=101.25(1), β=96.96(2), γ=108.06(2)°, V=901.2(4)Å3, Z=2, Dc=1.97g·cm-3, (MoKα)=0.71069Å, F(000)=520, μ=58.21cm-1, final R=0.040 for 2192 observed reflections, T=296K.The compound is amononuclear complex, containing a tetrahedrally coordinated zinc atom
1992, 3(5): 399-400
Abstract:
Monodispersed potymeric microparticles were prepared by seed-poly-merization.High performance packings were obtained for anion chromatography bycoating the surface-sutfonated partictes with quarternized latexes
Monodispersed potymeric microparticles were prepared by seed-poly-merization.High performance packings were obtained for anion chromatography bycoating the surface-sutfonated partictes with quarternized latexes
1992, 3(5): 401-402
Abstract:
Over Rh4(CO)1z-derived Rh/SiO2 catalyst, atmospheric hydroformylation and hydro-genation of ethylene are suggested to be structure sensitive and structure insensitive, res-pectively
Over Rh4(CO)1z-derived Rh/SiO2 catalyst, atmospheric hydroformylation and hydro-genation of ethylene are suggested to be structure sensitive and structure insensitive, res-pectively
1992, 3(5): 403-404
Abstract:
The dependence of the susceptibitity of LaGA1-xFexO3(x=0.2, 0.5, 6.8) on the concentration of Fe3+, teperature and magnetic fietdintensity were studied and the change of Neet point was observed.Some regularities were obtained for first time in this paper
The dependence of the susceptibitity of LaGA1-xFexO3(x=0.2, 0.5, 6.8) on the concentration of Fe3+, teperature and magnetic fietdintensity were studied and the change of Neet point was observed.Some regularities were obtained for first time in this paper
1992, 3(5): 405-406
Abstract:
The electrophoretic mobility of positively charged, cylindrically shaped α-FeO OHparticles dispersed in dilute sodium chloride solutions was measured at 25℃, as a function ofionic strength and pH using microelectrophoresis apparatus.The mobility data were processed through a number of selected relationships that representvarious stages of understanding of electrophoretic theory, culminating in the determination ofvalues of the electrokinetic charge and zeta potential of the colloid α-FeO OH/NaCl aq
The electrophoretic mobility of positively charged, cylindrically shaped α-FeO OHparticles dispersed in dilute sodium chloride solutions was measured at 25℃, as a function ofionic strength and pH using microelectrophoresis apparatus.The mobility data were processed through a number of selected relationships that representvarious stages of understanding of electrophoretic theory, culminating in the determination ofvalues of the electrokinetic charge and zeta potential of the colloid α-FeO OH/NaCl aq
