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2001 Volume 12 Issue 8
2001, 12(8): 659-662
Abstract:
Azides can be easily reduced to the corresponding amines with Sm/TMSCl/H2O (trace) system in excellent yields under mild and neutral conditions.
Azides can be easily reduced to the corresponding amines with Sm/TMSCl/H2O (trace) system in excellent yields under mild and neutral conditions.
2001, 12(8): 663-664
Abstract:
Poly (lactic acid) (PLA) was synthesized by microwave-assisted ring-opening poly-merization of D, L-lactide with stannous octanoate (SnOct2) as catalyst. Its weight-average molar mass (Mw) ranged from 39000 to 67000 and the polydispersity index from 1.3 to 1.7. The polymerization rate was much faster than that of the conventional thermal polymerization. A degradation of newly formed PLA in reaction mixture by microwave irradiation was observed.
Poly (lactic acid) (PLA) was synthesized by microwave-assisted ring-opening poly-merization of D, L-lactide with stannous octanoate (SnOct2) as catalyst. Its weight-average molar mass (Mw) ranged from 39000 to 67000 and the polydispersity index from 1.3 to 1.7. The polymerization rate was much faster than that of the conventional thermal polymerization. A degradation of newly formed PLA in reaction mixture by microwave irradiation was observed.
2001, 12(8): 665-666
Abstract:
The spin labeled 4'-Epi-N-trifuoroacetyldaunomycin derivatives 6-7 were conveniently synthesized from daunomycin in middle yield. The key steps were the protection of compd. 5 at 9-position and nucleophilic displacement of 5 with R.COOH and DBU at room temperature.
The spin labeled 4'-Epi-N-trifuoroacetyldaunomycin derivatives 6-7 were conveniently synthesized from daunomycin in middle yield. The key steps were the protection of compd. 5 at 9-position and nucleophilic displacement of 5 with R.COOH and DBU at room temperature.
2001, 12(8): 667-670
Abstract:
Two new lignans with dibenzocycloheptadiene skelectons have been synthesized by intramolecular nonphenolic oxidative coupling and rearrangement. The structures of these products have been identified by MS, UV, IR and NMR spectra.
Two new lignans with dibenzocycloheptadiene skelectons have been synthesized by intramolecular nonphenolic oxidative coupling and rearrangement. The structures of these products have been identified by MS, UV, IR and NMR spectra.
2001, 12(8): 671-674
Abstract:
Diphenylchlorin (DPC) and diphenylbacteriochlorin (DPBC) were synthesized for the first time from reduction of 5,10-diphenylporphyrin (DPP). As photosensitizers they have sizable absorption in the red region of the visible spectrum. The high yield of DPC-photosensitized generation of 1O2, and the EPR studies in homogenerous solution showed that the photodynamic action of DPP-based photosensitizers may proceed via type I and type Ⅱ machanisms.
Diphenylchlorin (DPC) and diphenylbacteriochlorin (DPBC) were synthesized for the first time from reduction of 5,10-diphenylporphyrin (DPP). As photosensitizers they have sizable absorption in the red region of the visible spectrum. The high yield of DPC-photosensitized generation of 1O2, and the EPR studies in homogenerous solution showed that the photodynamic action of DPP-based photosensitizers may proceed via type I and type Ⅱ machanisms.
2001, 12(8): 675-678
Abstract:
Several 14α-and 14β-bromo baccatin Ⅲ derivatives were synthesized by direct bromination and from silyl enol ether of 13-oxo-7-TES-baccatin Ⅲ. 14β-Hyroxy baccatin Ⅲ derivative was also obtained from the same silyl enol ether.
Several 14α-and 14β-bromo baccatin Ⅲ derivatives were synthesized by direct bromination and from silyl enol ether of 13-oxo-7-TES-baccatin Ⅲ. 14β-Hyroxy baccatin Ⅲ derivative was also obtained from the same silyl enol ether.
2001, 12(8): 679-682
Abstract:
The fullerene C60 and phthalocyanine co-grafted poly (epoxy propyl carbazole) (C60-CuPC-PEPC) was synthesized by Friedel-Crafts reaction. It was found that C60-CuPc-PEPC had good UV-Vis absorption property, whose active spectral range was expanded from UV to visible spectrum region, and exhibited better photoconductivity than CuPc-PEPC and PEPC. These improvements could be attributed to the interaction between C60, phthalocyanine and PEPC.
The fullerene C60 and phthalocyanine co-grafted poly (epoxy propyl carbazole) (C60-CuPC-PEPC) was synthesized by Friedel-Crafts reaction. It was found that C60-CuPc-PEPC had good UV-Vis absorption property, whose active spectral range was expanded from UV to visible spectrum region, and exhibited better photoconductivity than CuPc-PEPC and PEPC. These improvements could be attributed to the interaction between C60, phthalocyanine and PEPC.
2001, 12(8): 683-686
Abstract:
A new [60]fullerene dimer 2 in which two C60 units are covalently attached to a squarylium cyanine dye has been synthesized and characterized.
A new [60]fullerene dimer 2 in which two C60 units are covalently attached to a squarylium cyanine dye has been synthesized and characterized.
2001, 12(8): 687-690
Abstract:
p, p'-Diaminodiphenylmethane-Schiff bases (SB) of general formula (R)-phCH=N-ph-CH2-ph-N=CHph(R), where R is p-NO2, m-NO2, p-OH, o-OH, p-Cl,-H, p-OCH3, and sul-phonamide Schiff bases (SB) of general formula (R)-phCH=N-ph-SO2NH2, where R is p-NO2, m-NO2, p-OH, o-OH, p-Cl,-H, p-OCH3, were synthesized and their structure have been characterized by the melting pointing, 1HNMR, MS, and elemental analysis. They are thermolabile and undergo thermo-chromism and thermal decomposition after melting. The TG. and DSC measurement were recorded in dynamic air and interpreted.
p, p'-Diaminodiphenylmethane-Schiff bases (SB) of general formula (R)-phCH=N-ph-CH2-ph-N=CHph(R), where R is p-NO2, m-NO2, p-OH, o-OH, p-Cl,-H, p-OCH3, and sul-phonamide Schiff bases (SB) of general formula (R)-phCH=N-ph-SO2NH2, where R is p-NO2, m-NO2, p-OH, o-OH, p-Cl,-H, p-OCH3, were synthesized and their structure have been characterized by the melting pointing, 1HNMR, MS, and elemental analysis. They are thermolabile and undergo thermo-chromism and thermal decomposition after melting. The TG. and DSC measurement were recorded in dynamic air and interpreted.
2001, 12(8): 691-692
Abstract:
A series of 8-iminoquinoline derivatives nickel complexes were synthesized to proceed high activity in ethylene oligomerization.
A series of 8-iminoquinoline derivatives nickel complexes were synthesized to proceed high activity in ethylene oligomerization.
2001, 12(8): 693-696
Abstract:
Newlase F is a rude enzyme which contains triacylglycerol lipase and acid protease. Hydrolysis of dipeptide heptyl esters with Newlase F was studied in phosphate buffer-organic solvent by HPLC. When the Newlase F was level reached 5 mg/mL under mild condition (pH 7.0, 30℃), the lipase had the highest activity. The reaction was also affected greatly by organic solvents and their concentrations. It is found that protease in Newlase F does not hydrolyze amide bond under this condition (pH 7.0, r.t.).
Newlase F is a rude enzyme which contains triacylglycerol lipase and acid protease. Hydrolysis of dipeptide heptyl esters with Newlase F was studied in phosphate buffer-organic solvent by HPLC. When the Newlase F was level reached 5 mg/mL under mild condition (pH 7.0, 30℃), the lipase had the highest activity. The reaction was also affected greatly by organic solvents and their concentrations. It is found that protease in Newlase F does not hydrolyze amide bond under this condition (pH 7.0, r.t.).
2001, 12(8): 697-700
Abstract:
In an effort to investigate the use of short peptide chains as carriers of new anti-tumor agents, we synthesized four tripeptide-cytotoxic agent conjugates:DMQ-MA-Lys(DMQ-MA)-Phe-Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Ile-Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Val-Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Lys(Cbz)-Arg-Ome. The cytotoxic agent conjugated to the N-terminal and the ξ-amino group of Lysine of the tripeptide is 2,6-dimethoxyhydroquinone-3-mercaptoacetic acid (DMQ-MA). The tripeptides were synthesized by coupling protected amino acid residues according to Pfp/DCC methods (Pfp:pentafluorophenol, DCC:N,N'-dicyclohexyl-carbodiimide) in solution. Agarose gel electrophoresis showed that these compounds can cleave supercoiled DNA into open-circular form in drug concentration as low as 4-50 μM without H2O2 and UV irradiation. Further studies on their cytotoxicity for these conjugates are ongoing.
In an effort to investigate the use of short peptide chains as carriers of new anti-tumor agents, we synthesized four tripeptide-cytotoxic agent conjugates:DMQ-MA-Lys(DMQ-MA)-Phe-Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Ile-Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Val-Arg-Ome, DMQ-MA-Lys(DMQ-MA)-Lys(Cbz)-Arg-Ome. The cytotoxic agent conjugated to the N-terminal and the ξ-amino group of Lysine of the tripeptide is 2,6-dimethoxyhydroquinone-3-mercaptoacetic acid (DMQ-MA). The tripeptides were synthesized by coupling protected amino acid residues according to Pfp/DCC methods (Pfp:pentafluorophenol, DCC:N,N'-dicyclohexyl-carbodiimide) in solution. Agarose gel electrophoresis showed that these compounds can cleave supercoiled DNA into open-circular form in drug concentration as low as 4-50 μM without H2O2 and UV irradiation. Further studies on their cytotoxicity for these conjugates are ongoing.
2001, 12(8): 701-702
Abstract:
A novel soluble conjugated copolymer (propionic acid)-co-(propargyl alcohol) (PA-co-OHP) has been synthesized for the first time using a new palladium acetylide catalyst Pd(PPh3)2 (C≡CC(CH3)2OH)2 (PPB). Thin film resistive humidity sensor based on the copolymer doped with HClO4 was prepared. The impedance of the sensor changed from 103~107 W in 95%~30%RH, and the response of that is very quick (< 6 sec.). Preliminary results show the copolymer is a promising humidity sensitive material.
A novel soluble conjugated copolymer (propionic acid)-co-(propargyl alcohol) (PA-co-OHP) has been synthesized for the first time using a new palladium acetylide catalyst Pd(PPh3)2 (C≡CC(CH3)2OH)2 (PPB). Thin film resistive humidity sensor based on the copolymer doped with HClO4 was prepared. The impedance of the sensor changed from 103~107 W in 95%~30%RH, and the response of that is very quick (< 6 sec.). Preliminary results show the copolymer is a promising humidity sensitive material.
2001, 12(8): 703-704
Abstract:
2-methyl-5-propyl-7, 12-dihydroxy chromone-12-O-b-D-glucopyranoside was isolated from the stem of Cassia siamea. The structure was elucidated by chemical and spectral evidences.
2-methyl-5-propyl-7, 12-dihydroxy chromone-12-O-b-D-glucopyranoside was isolated from the stem of Cassia siamea. The structure was elucidated by chemical and spectral evidences.
2001, 12(8): 705-708
Abstract:
Three new saikosaponin-like compounds (named prostratoside F-H) were isolated from the whole plants of Polycarpon prostratum (Forssk.) Aschers. et Schwein. ex Aschers. By detailed spectroscopic analysis, their structures were determined as 13β, 28-epoxy-16-keto-22α, 23-dihydroxyolean-11-en-3β-yl-α-L-arabinopyranoside, 13β, 28-epoxy-16-keto-23-hydroxy-ole-an-11-en-3β-yl-α-L-arabinopyranoside and 13β, 28-epoxy-16-keto-22α-hydroxyolean-11-en-3β-yl-α-L-arabinopyranoside, respectively.
Three new saikosaponin-like compounds (named prostratoside F-H) were isolated from the whole plants of Polycarpon prostratum (Forssk.) Aschers. et Schwein. ex Aschers. By detailed spectroscopic analysis, their structures were determined as 13β, 28-epoxy-16-keto-22α, 23-dihydroxyolean-11-en-3β-yl-α-L-arabinopyranoside, 13β, 28-epoxy-16-keto-23-hydroxy-ole-an-11-en-3β-yl-α-L-arabinopyranoside and 13β, 28-epoxy-16-keto-22α-hydroxyolean-11-en-3β-yl-α-L-arabinopyranoside, respectively.
2001, 12(8): 709-710
Abstract:
A new dolabellane diterpene 1, named as hydroclathrol, has been isolated from the alga Hydroclathrus tenuis. Its structure has been determined on the basis of spectral analysis as 1, 4, 8-trimethyl-14-isopropyl-bicyclo [9, 3, 0]-4 (Z), 8(E), 11(Z)-tetradeca triene-6-ol.
A new dolabellane diterpene 1, named as hydroclathrol, has been isolated from the alga Hydroclathrus tenuis. Its structure has been determined on the basis of spectral analysis as 1, 4, 8-trimethyl-14-isopropyl-bicyclo [9, 3, 0]-4 (Z), 8(E), 11(Z)-tetradeca triene-6-ol.
2001, 12(8): 711-712
Abstract:
A new spirosecokaurenoid, enanderinanin F 1 and its C-6 epimer, angustifolin were isolated from the aerial parts of Isodon enanderianus. The structure of 1 was determined on the basis of spectral data, especially by 2D techniques. The 13C NMR data of angustifolin were revised by 2D NMR.
A new spirosecokaurenoid, enanderinanin F 1 and its C-6 epimer, angustifolin were isolated from the aerial parts of Isodon enanderianus. The structure of 1 was determined on the basis of spectral data, especially by 2D techniques. The 13C NMR data of angustifolin were revised by 2D NMR.
2001, 12(8): 713-714
Abstract:
The thermal decomposition of 2, 2'-azobis (isobutyronitrile) (AIBN) in supercritical CO2 with cosolvent methanol or cyclohexane has been studied by using UV/Vis spectroscopic method at 335.15 K and at 12.0 MPa and 14.0 MPa. Both of the cosolvents can accelerate the decomposition rate, and the effect of methanol is more significant than that of the cyclohexane.
The thermal decomposition of 2, 2'-azobis (isobutyronitrile) (AIBN) in supercritical CO2 with cosolvent methanol or cyclohexane has been studied by using UV/Vis spectroscopic method at 335.15 K and at 12.0 MPa and 14.0 MPa. Both of the cosolvents can accelerate the decomposition rate, and the effect of methanol is more significant than that of the cyclohexane.
2001, 12(8): 715-718
Abstract:
A novel heterogeneous oscillator, the Cu2+-catalyzed oscillatory oxidation of ascorbic acid (Vitamin C) in aqueous solution by O2 flow was reported. Both the potential oscillations on Pt-electrode corresponding to [Cu2+] and the absorbance oscillations at λ=260 nm corresponding to [ascorbic acid] were observed. Oscillations in the completely homogeneous system were also observed. Effects of several factors on the oscillations were investigated.
A novel heterogeneous oscillator, the Cu2+-catalyzed oscillatory oxidation of ascorbic acid (Vitamin C) in aqueous solution by O2 flow was reported. Both the potential oscillations on Pt-electrode corresponding to [Cu2+] and the absorbance oscillations at λ=260 nm corresponding to [ascorbic acid] were observed. Oscillations in the completely homogeneous system were also observed. Effects of several factors on the oscillations were investigated.
2001, 12(8): 719-722
Abstract:
By using AM1 method, the structures and electronic properties of N-methyl-2-(2'-thio-phene)-pyrrolo [3,4]C60 (MTPC) and N-methyl-pyrrolo [3,4]C60 (MPC) have been studied. Based on the AM1 geometry optimizing, the electronic spectra and second-order nonlinear optical polarizabil-ities (β) of MTPC and MPC were calculated by using INDO/SCI method combined with Sum-Over-States (SOS) expression.
By using AM1 method, the structures and electronic properties of N-methyl-2-(2'-thio-phene)-pyrrolo [3,4]C60 (MTPC) and N-methyl-pyrrolo [3,4]C60 (MPC) have been studied. Based on the AM1 geometry optimizing, the electronic spectra and second-order nonlinear optical polarizabil-ities (β) of MTPC and MPC were calculated by using INDO/SCI method combined with Sum-Over-States (SOS) expression.
2001, 12(8): 723-726
Abstract:
Three density functional theory methods (DFT) have been used to investigate the H2+F→HF+H reaction comparing with the Hartree-Fock method and Moller-Plesset (MP2) perturbation theory method. Through the analysis of the vibrational mode and vibrational frequency in the reaction process, the reaction mechanism has been discussed. The activation energy, the reorganization energy and rate constant of the ET reaction are calculated at semi-quantitative level.
Three density functional theory methods (DFT) have been used to investigate the H2+F→HF+H reaction comparing with the Hartree-Fock method and Moller-Plesset (MP2) perturbation theory method. Through the analysis of the vibrational mode and vibrational frequency in the reaction process, the reaction mechanism has been discussed. The activation energy, the reorganization energy and rate constant of the ET reaction are calculated at semi-quantitative level.
2001, 12(8): 727-730
Abstract:
The two channels of the CH3OH+Cl hydrogen abstraction reaction, leading to the final products CH2OH+HCl (i) and CH3O+HCl (ii), have been studied by performing ab initio MP2 calculations with the triplet split-valence polarization basis sets. For each of the two channels the following simple reaction path is predicted:reactants → transition state → intermediate → products. The previously reported complicated paths2 calculated without using the IRC technique are criticized. Our calculations indicate that channel (i) is exothermic and has a negligible energy barrier while channel (ii) is endothermic and has a substantial energy barrier. These results imply that channel (i) is favorable, which is in line with experiment.
The two channels of the CH3OH+Cl hydrogen abstraction reaction, leading to the final products CH2OH+HCl (i) and CH3O+HCl (ii), have been studied by performing ab initio MP2 calculations with the triplet split-valence polarization basis sets. For each of the two channels the following simple reaction path is predicted:reactants → transition state → intermediate → products. The previously reported complicated paths2 calculated without using the IRC technique are criticized. Our calculations indicate that channel (i) is exothermic and has a negligible energy barrier while channel (ii) is endothermic and has a substantial energy barrier. These results imply that channel (i) is favorable, which is in line with experiment.
2001, 12(8): 731-732
Abstract:
The peroxotitanium-substituted heteropolytungstate α-K7GaW11(TiO2)O39&·11H2O has been synthesized and characterized by elemental analysis, IR, UV, 183W NMR and electrochemistry. 183W NMR spectrum consists of six lines with intensity ratio 2:2:1:2:2:2, indicated that the TiO2 occupied the empty octahedral site of the GaW11 anion forming a polyanion with Cs symmetry. The characteristic charge-transfer absorption band O22-→Ti at 385 nm occurs in the UV spectrum. The polarographic reduction potential of O22- at ca.+0.87 V has been found.
The peroxotitanium-substituted heteropolytungstate α-K7GaW11(TiO2)O39&·11H2O has been synthesized and characterized by elemental analysis, IR, UV, 183W NMR and electrochemistry. 183W NMR spectrum consists of six lines with intensity ratio 2:2:1:2:2:2, indicated that the TiO2 occupied the empty octahedral site of the GaW11 anion forming a polyanion with Cs symmetry. The characteristic charge-transfer absorption band O22-→Ti at 385 nm occurs in the UV spectrum. The polarographic reduction potential of O22- at ca.+0.87 V has been found.
2001, 12(8): 733-736
Abstract:
Chemical oxidation and metal intercalation of natural grahite was utilized to increase the capactiy and enhance the cycle propety of graphite anods in lithium ion batteries
Chemical oxidation and metal intercalation of natural grahite was utilized to increase the capactiy and enhance the cycle propety of graphite anods in lithium ion batteries
2001, 12(8): 737-740
Abstract:
Thermally stable mesoporous silica and Ti-containing molecular sieves have been synthesized at mild temperature using low-cost and biodegradable——amphoteric tetradecyl betaine as template. The physicochemical characterizations proved that Ti(Ⅳ) could be incorporated in the mesoporous struture.
Thermally stable mesoporous silica and Ti-containing molecular sieves have been synthesized at mild temperature using low-cost and biodegradable——amphoteric tetradecyl betaine as template. The physicochemical characterizations proved that Ti(Ⅳ) could be incorporated in the mesoporous struture.
2001, 12(8): 741-744
Abstract:
Small Angle X-ray Scattering (SAXS) experiment using Synchrotron Radiation as X-ray source was used to determine the average wall thickness of mesoporous silica prepared by condensation of tetraethylorthosilicate (TEOS) using non-ionic alkylpolyethyleneoxide (AEO9) surfactant as templates. The results agreed with that of high-resolution TEM (HRTEM) measurement.
Small Angle X-ray Scattering (SAXS) experiment using Synchrotron Radiation as X-ray source was used to determine the average wall thickness of mesoporous silica prepared by condensation of tetraethylorthosilicate (TEOS) using non-ionic alkylpolyethyleneoxide (AEO9) surfactant as templates. The results agreed with that of high-resolution TEM (HRTEM) measurement.
2001, 12(8): 745-746
Abstract:
The thermogravimetry(TG) and derivative thermogravimetry(DTG) curves of the thermal decomposition reaction of calcium carbonate have been measured at five different heating rates. The kinetic parameters and the reaction mechanism of the reaction were evaluated from analysis of the TG and DTG curves by using the Ozawa method, the combined integral and differential methods and the reduced equations derived by us.
The thermogravimetry(TG) and derivative thermogravimetry(DTG) curves of the thermal decomposition reaction of calcium carbonate have been measured at five different heating rates. The kinetic parameters and the reaction mechanism of the reaction were evaluated from analysis of the TG and DTG curves by using the Ozawa method, the combined integral and differential methods and the reduced equations derived by us.
2001, 12(8): 747-750
Abstract:
Non-ionically templated organo-modified MSU-2 mesoporous silicas have been prepared in neutral medium by co-condensation TEOS and vinyltriexoylsiloxane (VTES) and exhibit highly symmetric bimodal mesopore systems. A bromination reaction of V-MSU-2 provides evidence for attachment of most vinyl groups to the accessible surface within the channels. Further, siliceous MSU-2 materials with double pore size have been obtained from calcination of so-produced organo-modified MSU-2 and demonstrate the immense flexibility of the non-ionic templating system.
Non-ionically templated organo-modified MSU-2 mesoporous silicas have been prepared in neutral medium by co-condensation TEOS and vinyltriexoylsiloxane (VTES) and exhibit highly symmetric bimodal mesopore systems. A bromination reaction of V-MSU-2 provides evidence for attachment of most vinyl groups to the accessible surface within the channels. Further, siliceous MSU-2 materials with double pore size have been obtained from calcination of so-produced organo-modified MSU-2 and demonstrate the immense flexibility of the non-ionic templating system.
2001, 12(8): 751-752
Abstract:
Nanocrystalline CdTe thin films were prepared by asymmetric rectangular pulse electrodeposition in organic solution at 110℃. STM image shows a porous network morphology constructed by interconnected spherical CdTe crystallites with a mean diameter of 4.2 nm. A pronounced size quantization was indicated in the action and absorption spectra. Potentials dependence dual conductive behavior was revealed in the photocurrent-potential (I-V) curves.
Nanocrystalline CdTe thin films were prepared by asymmetric rectangular pulse electrodeposition in organic solution at 110℃. STM image shows a porous network morphology constructed by interconnected spherical CdTe crystallites with a mean diameter of 4.2 nm. A pronounced size quantization was indicated in the action and absorption spectra. Potentials dependence dual conductive behavior was revealed in the photocurrent-potential (I-V) curves.
