Login In
2001 Volume 12 Issue 7
2001, 12(7): 565-568
Abstract:
A variety of aldehydes were converted into acylals in excellent ields with acetic anhydride in the presence of a catalytic amount of tin (Ⅳ) chloride supported on silica gel at room temperature.
A variety of aldehydes were converted into acylals in excellent ields with acetic anhydride in the presence of a catalytic amount of tin (Ⅳ) chloride supported on silica gel at room temperature.
2001, 12(7): 569-570
Abstract:
In this letter, (R)-1,1-diphenyl-2-mercapto-3-methyl-1-butanol was synthesized from L-valinc and two synthetic routes have been tried.
In this letter, (R)-1,1-diphenyl-2-mercapto-3-methyl-1-butanol was synthesized from L-valinc and two synthetic routes have been tried.
2001, 12(7): 571-574
Abstract:
(S)-2-(6'-methoxyl-α-naphthyl) propionic acid ((S)-Naproxen, ee 99%) has been prepared starting from (6-methoxyl-α-naphthyl)propan-1-one and D-sorbitol under SmCl3catalysis.
(S)-2-(6'-methoxyl-α-naphthyl) propionic acid ((S)-Naproxen, ee 99%) has been prepared starting from (6-methoxyl-α-naphthyl)propan-1-one and D-sorbitol under SmCl3catalysis.
2001, 12(7): 575-578
Abstract:
1,4-anhydro-2-triflyl-3,5-O-benzenylidene-L-xylitol (5) was constructed in six steps from protected D-xylose. Substitution of 5 with protected 8-bromoinosine 6 gave the key intermediate 5'-O-TBS-2',3'-di-O-acetyl-N1-(2"-deoxy-1",4"-anhydro-3",5"-O-benzenylidene-Llyxitol-2"-yl)-8-bromoinosine (14). Selective removal of 5'-O-TBS-group gave the corresponding 5'-O-phosphorodianilidate 4 though phosphorylation, which was characterized by X-ray crystallographic analysis.
1,4-anhydro-2-triflyl-3,5-O-benzenylidene-L-xylitol (5) was constructed in six steps from protected D-xylose. Substitution of 5 with protected 8-bromoinosine 6 gave the key intermediate 5'-O-TBS-2',3'-di-O-acetyl-N1-(2"-deoxy-1",4"-anhydro-3",5"-O-benzenylidene-Llyxitol-2"-yl)-8-bromoinosine (14). Selective removal of 5'-O-TBS-group gave the corresponding 5'-O-phosphorodianilidate 4 though phosphorylation, which was characterized by X-ray crystallographic analysis.
2001, 12(7): 579-580
Abstract:
trans-3, 3b, 4, 9b, 10, ll-Hexahydro-6-methoxy-9b-methyl-7-(l-methylethyl) phenanthro {1,2-c[furan-l,5-dione]} was synthesized with good yield in two steps from triptophenolide methyl ether under mild conditions.
trans-3, 3b, 4, 9b, 10, ll-Hexahydro-6-methoxy-9b-methyl-7-(l-methylethyl) phenanthro {1,2-c[furan-l,5-dione]} was synthesized with good yield in two steps from triptophenolide methyl ether under mild conditions.
2001, 12(7): 581-584
Abstract:
Nucleophilic additions to endo-tricyclo [5.2.1.02.6]deca-2(6),8-dien-3-one 4 are described.Experimental results show high preference for exo-facial attack to the enone moiety of tricyclodecadienone. Steric hindrance is the main kinetically controlling factor in the nucleophilic reaction. The shielding effect and the stabilizing effect of the norbornene double bond favor the exo-facial attack also.
Nucleophilic additions to endo-tricyclo [5.2.1.02.6]deca-2(6),8-dien-3-one 4 are described.Experimental results show high preference for exo-facial attack to the enone moiety of tricyclodecadienone. Steric hindrance is the main kinetically controlling factor in the nucleophilic reaction. The shielding effect and the stabilizing effect of the norbornene double bond favor the exo-facial attack also.
2001, 12(7): 585-588
Abstract:
Synthesis of highly strained tetracyclic ketones was achieved by cyclopropanation or epoxidation of tricyclodecenone 1. An unusual formation of α-methoxy β-hydroxy ketone from an α,β-unsaturated enone system via Payne rearrangement was reported.
Synthesis of highly strained tetracyclic ketones was achieved by cyclopropanation or epoxidation of tricyclodecenone 1. An unusual formation of α-methoxy β-hydroxy ketone from an α,β-unsaturated enone system via Payne rearrangement was reported.
2001, 12(7): 589-592
Abstract:
An aliphatic polyester, poly(hexalene adipate) (PHA) and an aliphatic copolyester, poly (hexalene adipate succinate) (PHAS) were synthesized by direct condensation of corresponding binary acid and binary alcohol in the presence of a catalyst, p-toluene sulfonic acid. The biodegradation of these polyesters were studied in the laboratory by enzyme attack and outdoor soil burial. The results show that these polyesters have good biodegradability and the copolyester PHAS, even displayed a better biodegradability than the polyester PHA. In the presence of Penicillium chrysogenum the weight loss reached 18.3% for the PHAS (film thickness 1.0 mm)and 9.1% for the PHA (film thickness 1.0 mm) after 28 days. Outdoor soil burial tests indicate that these polyesters also have good biodegradability in natural conditions. The weight loss reached 14.2% for PHAS (film thickness 0.1 mm) and 6.7% for PHA (film thickness 0.1mm) after burying in soil for 36 days.
An aliphatic polyester, poly(hexalene adipate) (PHA) and an aliphatic copolyester, poly (hexalene adipate succinate) (PHAS) were synthesized by direct condensation of corresponding binary acid and binary alcohol in the presence of a catalyst, p-toluene sulfonic acid. The biodegradation of these polyesters were studied in the laboratory by enzyme attack and outdoor soil burial. The results show that these polyesters have good biodegradability and the copolyester PHAS, even displayed a better biodegradability than the polyester PHA. In the presence of Penicillium chrysogenum the weight loss reached 18.3% for the PHAS (film thickness 1.0 mm)and 9.1% for the PHA (film thickness 1.0 mm) after 28 days. Outdoor soil burial tests indicate that these polyesters also have good biodegradability in natural conditions. The weight loss reached 14.2% for PHAS (film thickness 0.1 mm) and 6.7% for PHA (film thickness 0.1mm) after burying in soil for 36 days.
2001, 12(7): 593-594
Abstract:
A novel poly (ether imide)s containing phthalazinone and isopropyl moieties derived from 2-(4-aminophenyl)-4-[4-(4-aminophenoxy) phenyl]-phthalazin-l-one and bisphenol-A diphthalic anhydride was synthesized by one-step solution condensation polymerization in m-cresol. The polymer was characterized by FTIR, NMR, molecular weights, glass transition temperature,thermal degradation temperature and WAXD.
A novel poly (ether imide)s containing phthalazinone and isopropyl moieties derived from 2-(4-aminophenyl)-4-[4-(4-aminophenoxy) phenyl]-phthalazin-l-one and bisphenol-A diphthalic anhydride was synthesized by one-step solution condensation polymerization in m-cresol. The polymer was characterized by FTIR, NMR, molecular weights, glass transition temperature,thermal degradation temperature and WAXD.
2001, 12(7): 595-596
Abstract:
The dendritic polyarylether 2-bromoisobutyrate as the macromolecular initiator for the controlled free radical polymerization of styrene was investigated. The polymerization was carried out with CuBr/2,2'-bipyridine catalyst at 110℃. It is found that the hybrid dendritic-linear block copolymers possess well-defined molecular weights and low polydispersities.
The dendritic polyarylether 2-bromoisobutyrate as the macromolecular initiator for the controlled free radical polymerization of styrene was investigated. The polymerization was carried out with CuBr/2,2'-bipyridine catalyst at 110℃. It is found that the hybrid dendritic-linear block copolymers possess well-defined molecular weights and low polydispersities.
2001, 12(7): 598-600
Abstract:
A new eudesmanolide and a new aromatic derivative were isolated from the roots of Carpesium cernuun. Their structures were elucidated as 13-hydroxy-5,7(11)-eudesmadien-12,8-olide and 3-methyl-8-acetoxy-9,10-diisobutyryloxy-p-cymene by spectral methods (EIMS, FAB-MS, 1D and 2D NMR).
A new eudesmanolide and a new aromatic derivative were isolated from the roots of Carpesium cernuun. Their structures were elucidated as 13-hydroxy-5,7(11)-eudesmadien-12,8-olide and 3-methyl-8-acetoxy-9,10-diisobutyryloxy-p-cymene by spectral methods (EIMS, FAB-MS, 1D and 2D NMR).
2001, 12(7): 601-602
Abstract:
Two new eremophilane sesquiterpenes 33-angeloyloxy-8α-hydroxy-6β-methoxy eremophil-7 (11), 9 (10)-dien-8, 12-olide (1) and 3β-angeloyloxy-6β, 8α-dihydroxy-eremophi-7(11), 9 (10)-dien-8, 12-olide (2) were isolated from Cacalia ainsliaeflora. Their structures were established by spectroscopic methods and 2D NMR experiments.
Two new eremophilane sesquiterpenes 33-angeloyloxy-8α-hydroxy-6β-methoxy eremophil-7 (11), 9 (10)-dien-8, 12-olide (1) and 3β-angeloyloxy-6β, 8α-dihydroxy-eremophi-7(11), 9 (10)-dien-8, 12-olide (2) were isolated from Cacalia ainsliaeflora. Their structures were established by spectroscopic methods and 2D NMR experiments.
2001, 12(7): 603-606
Abstract:
Three derivatives of micromelin, named hydramicromelins A-C (1-3), were isolated from the aerial part of Micromelum integerrimum (Buch.-Ham) Roem., respectively.Hydramicromelins A-C (1-3) were epimers which possessed the same plane structure and molecular formula. Their structures were elucidated based on MS and NMR data. The relative configurations of 1-3 were established by NOE analysis.
Three derivatives of micromelin, named hydramicromelins A-C (1-3), were isolated from the aerial part of Micromelum integerrimum (Buch.-Ham) Roem., respectively.Hydramicromelins A-C (1-3) were epimers which possessed the same plane structure and molecular formula. Their structures were elucidated based on MS and NMR data. The relative configurations of 1-3 were established by NOE analysis.
2001, 12(7): 607-610
Abstract:
Two new cyclopeptides, leiocyclocin A (1), B (2), were isolated from the seeds of Goniothalamus leiocarpus. Their structures were elucidated by means of spectral and chemical methods.
Two new cyclopeptides, leiocyclocin A (1), B (2), were isolated from the seeds of Goniothalamus leiocarpus. Their structures were elucidated by means of spectral and chemical methods.
2001, 12(7): 611-612
Abstract:
Gnetupendin C, a new dimer coupled by a resveratrol and an oxyresveratrol unit, was isolated from the lianas of Gnetum pendulum C.Y. Cheng (Gnetaceae). Its structure was established on the basis of spectroscopic evidence, especially 2D techniques.
Gnetupendin C, a new dimer coupled by a resveratrol and an oxyresveratrol unit, was isolated from the lianas of Gnetum pendulum C.Y. Cheng (Gnetaceae). Its structure was established on the basis of spectroscopic evidence, especially 2D techniques.
2001, 12(7): 613-616
Abstract:
A new spirostanol saponin presenting strong activity of inducing morphological deformation of Pyricularia oryzae mycelia was isolated from Dioscorea futshauensis R. Kunth by bioactivity-guided fractionation. The structure was established as (25S)-spirost-5-en-3β,27-diol-3-O-[α-L-rhamnopyranosyl (1→2)-β-D -glucopyranosyl (l→3)]-β-D-glucopyranoside on the basis of chemical evidences and spectral analysis, especially by 2D-NMR techniques.
A new spirostanol saponin presenting strong activity of inducing morphological deformation of Pyricularia oryzae mycelia was isolated from Dioscorea futshauensis R. Kunth by bioactivity-guided fractionation. The structure was established as (25S)-spirost-5-en-3β,27-diol-3-O-[α-L-rhamnopyranosyl (1→2)-β-D -glucopyranosyl (l→3)]-β-D-glucopyranoside on the basis of chemical evidences and spectral analysis, especially by 2D-NMR techniques.
2001, 12(7): 617-618
Abstract:
A new benzosesquiterpenoid dimer, 3",3"'-bispolycerasoidol (1), along with its monomer, polycerasoidol, were isolated from the dried leaves of Polyalthia cheliensis Hu. The structure of 1 was established by spectroscopic methods.
A new benzosesquiterpenoid dimer, 3",3"'-bispolycerasoidol (1), along with its monomer, polycerasoidol, were isolated from the dried leaves of Polyalthia cheliensis Hu. The structure of 1 was established by spectroscopic methods.
2001, 12(7): 619-622
Abstract:
A strong interaction between double stranded calf-thymus DNA (ds-DNA) and epinephrine but no interaction between single stranded calf-thymus DNA (ss-DNA) and epinephrine were observed by the use of UV-spectroscopy and cyclic voltammetry. It is suggested that the interaction leads to an intercalation of EP molecules into the groove of ds-DNA and the formation of ds-DNA(EP)n complex.
A strong interaction between double stranded calf-thymus DNA (ds-DNA) and epinephrine but no interaction between single stranded calf-thymus DNA (ss-DNA) and epinephrine were observed by the use of UV-spectroscopy and cyclic voltammetry. It is suggested that the interaction leads to an intercalation of EP molecules into the groove of ds-DNA and the formation of ds-DNA(EP)n complex.
2001, 12(7): 623-624
Abstract:
Capillary electrophoresis (CE) method was developed for the separation and quantification of reduced glutathione (GSH), oxidized glutathione (GSSG) and glutathione sulphonic acid (GSO3H). Baseline separation was obtained within five minutes. The effects of reaction time and molar ratio of hypochlorous acid (HOCI) to GSH on the oxidation of GSH were investigated.
Capillary electrophoresis (CE) method was developed for the separation and quantification of reduced glutathione (GSH), oxidized glutathione (GSSG) and glutathione sulphonic acid (GSO3H). Baseline separation was obtained within five minutes. The effects of reaction time and molar ratio of hypochlorous acid (HOCI) to GSH on the oxidation of GSH were investigated.
2001, 12(7): 625-728
Abstract:
A novel amperometric biosensor for the detection of hydrogen peroxide is described.The biosensor was constructed by electrodepositing HRP/PPy membrane on the surface of ferrocenecarboxylic acid mediated sol-gel derived composite carbon electrode. The biosensor gives response to hydrogen peroxide in a few seconds with detection limit of 5×l0-7 mol · L-1 (based on signal:noise=3). Linear range is up to 0.2 mmol · L-1.
A novel amperometric biosensor for the detection of hydrogen peroxide is described.The biosensor was constructed by electrodepositing HRP/PPy membrane on the surface of ferrocenecarboxylic acid mediated sol-gel derived composite carbon electrode. The biosensor gives response to hydrogen peroxide in a few seconds with detection limit of 5×l0-7 mol · L-1 (based on signal:noise=3). Linear range is up to 0.2 mmol · L-1.
2001, 12(7): 629-630
Abstract:
Layer-by-layer {PDDA/Hb}n films were assembled by means of alternate adsorption of positively charged poly (diallyldimethyl ammonium) (PDDA) and negatively charged hemoglobin (Hb) at pH 9.2 from their aqueous solutions on pyrolytic graphite (PG) electrodes. Film growth during adsorption cycles was demonstrated by cyclic voltammetry and UV-Vis spectroscopy.Direct electrochemistry of Hb in {PDDA/Hb}n films on PG was studied.
Layer-by-layer {PDDA/Hb}n films were assembled by means of alternate adsorption of positively charged poly (diallyldimethyl ammonium) (PDDA) and negatively charged hemoglobin (Hb) at pH 9.2 from their aqueous solutions on pyrolytic graphite (PG) electrodes. Film growth during adsorption cycles was demonstrated by cyclic voltammetry and UV-Vis spectroscopy.Direct electrochemistry of Hb in {PDDA/Hb}n films on PG was studied.
2001, 12(7): 631-634
Abstract:
The synthesis and upconverted fluorescent properties of a series of organic compounds with the structure:donor/bridge/acceptor, and different side-chains are reported. The results show that the compounds with different side-chains exhibit different two-photon induced fluorescent properties, although they have the same main donor/bridge/acceptor structure.
The synthesis and upconverted fluorescent properties of a series of organic compounds with the structure:donor/bridge/acceptor, and different side-chains are reported. The results show that the compounds with different side-chains exhibit different two-photon induced fluorescent properties, although they have the same main donor/bridge/acceptor structure.
2001, 12(7): 631-634
Abstract:
The method for the sepration and determination of trace Cr(VI) exiting in mass Cr(Ⅲ) has been researched. The method is highly sensitive and less interference, but is simple and useful for analysis trace Cr(VI).
The method for the sepration and determination of trace Cr(VI) exiting in mass Cr(Ⅲ) has been researched. The method is highly sensitive and less interference, but is simple and useful for analysis trace Cr(VI).
2001, 12(7): 637-640
Abstract:
The conformation of mono-6-O-p-nitrobenzoyl-β-cyclodextrin was studied with B3LYP/6-311g**//PM3 calculations in vacuum and in water solution. It was concluded that the p-nitrobenzoyl group of the molecule should be located above the primary hydroxyls of the cyclodextrin instead of being completely enclosed by the cavity. It was proposed that the behavior might be caused by the requirement of a cis ester bond in the self-included conformation of the molecule.
The conformation of mono-6-O-p-nitrobenzoyl-β-cyclodextrin was studied with B3LYP/6-311g**//PM3 calculations in vacuum and in water solution. It was concluded that the p-nitrobenzoyl group of the molecule should be located above the primary hydroxyls of the cyclodextrin instead of being completely enclosed by the cavity. It was proposed that the behavior might be caused by the requirement of a cis ester bond in the self-included conformation of the molecule.
2001, 12(7): 641-644
Abstract:
Kinetic model of hypophosphite oxidation on a nickel electrode was studied in D2Osolution in order to reach a better understanding of the oxidation mechanism. In the model the electrooxidation of hypophosphite undergo a H abstraction of hypophosphite from the P-H bond to form the phosphorus-centered radical PHO2-, which subsequently is electrochemically reacted with water to form the final product, phosphite. The kinetic equations were derived, and the kinetic parameters were obtained from a comparison of experimental results and the kinetic equations. The process of hypophosphite electrooxidation could be well simulated by this model
Kinetic model of hypophosphite oxidation on a nickel electrode was studied in D2Osolution in order to reach a better understanding of the oxidation mechanism. In the model the electrooxidation of hypophosphite undergo a H abstraction of hypophosphite from the P-H bond to form the phosphorus-centered radical PHO2-, which subsequently is electrochemically reacted with water to form the final product, phosphite. The kinetic equations were derived, and the kinetic parameters were obtained from a comparison of experimental results and the kinetic equations. The process of hypophosphite electrooxidation could be well simulated by this model
2001, 12(7): 645-646
Abstract:
By using the iterative method in functional theory, an analytic expression of the Poisson-Boltzmann equation (PB eq.), which describes the distribution of the potential of electrical double layer of a spherical micelle, has been carried out under the general potential condition for the first time. The method also can give the radius, the surface potential, and the thickness of the layer.
By using the iterative method in functional theory, an analytic expression of the Poisson-Boltzmann equation (PB eq.), which describes the distribution of the potential of electrical double layer of a spherical micelle, has been carried out under the general potential condition for the first time. The method also can give the radius, the surface potential, and the thickness of the layer.
2001, 12(7): 647-650
Abstract:
The catalytic property of AlCl3 catalyst immobilized on γ-Al2O3 for isobutene polymerization has been studied. It was found that the activity, selectivity and stability of the catalyst are dependent greatly on geometric characteristic of the pore structure and size of catalyst.Although the activity and selectivity of the catalysts with micro-and meso-pore structure are all high in initial stage, but their stability is low, while those with bimodal meso-and macro-pore structure are excellent. Increasing granularity of the catalyst (particle become fine) brings about an increase in isobutene conversion, but a decrease in selectivity, resulting in lower average molecular weight and its broader distribution.
The catalytic property of AlCl3 catalyst immobilized on γ-Al2O3 for isobutene polymerization has been studied. It was found that the activity, selectivity and stability of the catalyst are dependent greatly on geometric characteristic of the pore structure and size of catalyst.Although the activity and selectivity of the catalysts with micro-and meso-pore structure are all high in initial stage, but their stability is low, while those with bimodal meso-and macro-pore structure are excellent. Increasing granularity of the catalyst (particle become fine) brings about an increase in isobutene conversion, but a decrease in selectivity, resulting in lower average molecular weight and its broader distribution.
2001, 12(7): 651-654
Abstract:
N,N,N',N'-tetra [(2-benzimidazolyl) methyl]-l,2-ethanediamine (EDTB) lanthanidechloride complexes were prepared (Ln3+=Eu3+, Tb3+or Gd3+). The results of single crystal X-ray structural analysis show that [(EDTB) GdCl2]Cl(C2H5OH)(H2O)2 crystal is in space group P21/c with a=8.848(2) Å, b=26.313(5) Å, c=18.929(4) Å, β=97.82 (3)°, V=4366(2) Å3, Z=4. The luminescent properties of the terbium and europium complexes have been studied.
N,N,N',N'-tetra [(2-benzimidazolyl) methyl]-l,2-ethanediamine (EDTB) lanthanidechloride complexes were prepared (Ln3+=Eu3+, Tb3+or Gd3+). The results of single crystal X-ray structural analysis show that [(EDTB) GdCl2]Cl(C2H5OH)(H2O)2 crystal is in space group P21/c with a=8.848(2) Å, b=26.313(5) Å, c=18.929(4) Å, β=97.82 (3)°, V=4366(2) Å3, Z=4. The luminescent properties of the terbium and europium complexes have been studied.
2001, 12(7): 655-658
Abstract:
The nature of bonding in the title compounds has been studied by using CASSCF and FOCl techniques. The ground states of WC and WN are found to be 3Δ and 4∑- state arising primarily from:...1σ2σ21π41δ13σ1 and...1σ2σ21π41δ23σ1 configuration respectively. WC shows a strong character of covalent bond while WN have obvious character of ionic bond and the dissociation energy of WN is larger than that of WC (6.15 and 5.41 eV respective).
The nature of bonding in the title compounds has been studied by using CASSCF and FOCl techniques. The ground states of WC and WN are found to be 3Δ and 4∑- state arising primarily from:...1σ2σ21π41δ13σ1 and...1σ2σ21π41δ23σ1 configuration respectively. WC shows a strong character of covalent bond while WN have obvious character of ionic bond and the dissociation energy of WN is larger than that of WC (6.15 and 5.41 eV respective).
