2009 Volume 20 Issue 10

Determination of hydroxyl radical in Fenton system
Yan Fen Fang , An Ping Deng , Ying Ping Huang
2009, 20(10): 235-1240  doi: 10.1016/j.cclet.2009.05.004
[Abstract](167) [FullText HTML] [PDF 367KB](0)
Abstract:
Under visible light illumination, 2,3-diaminophenazine (DAPN) was generated from the oxidation of o-phenylenediamine (OPDA) in Fe3+/H 2O2 solution.Hydroxyl radical (·OH) produced in this system was determined by directly measuring the concentration of DAPN.In comparison with the traditional methods, the determination is more accurate and simple.
A new sesquiterpene trilactone from the roots of Ginkgo biloba
Ping Yu , Jing Yu Liang
2009, 20(10): 1124-1126  doi: 10.1016/j.cclet.2009.05.026
[Abstract](159) [FullText HTML] [PDF 221KB](0)
Abstract:
A new sesquiterpene trilactone, named bilobanol (1), along with four known terpene trilactones (ginkgolide A, B, C and bilobalide) were isolated from the roots of Ginkgo biloba collected in Jiangsu Province, China.The structure elucidation was accomplished by 1D and 2D NMR methods, HR-ESI-MS, and CD spectrum.
Synthesis and cytotoxicity of 28-carboxymethoxy lupanetriterpenoids.Preference of 28-O-acylation over 28-O-alkylation of betulin by ethyl bromoacetate
Aye Aye Mar , Ali Koohang , Nathan D. Majewski , Erika L. Szotek , David A. Eiznhamer , Michael T. Flavin , Ze Qi Xu
2009, 20(10): 1141-1144  doi: 10.1016/j.cclet.2009.04.001
[Abstract](162) [FullText HTML] [PDF 291KB](0)
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28-Carboxymethoxy lupane tritepenoids 3 and 4 were synthesized by alkylation of betulin with the THP protected 2-hydroxyethyl iodide followed by oxidation and reduction.Direct reaction of betulin (5) or betulone (10) with ethyl bromoacetate led to 28-O-acylation, instead of 28-O-alkylation.The targeted compounds 3 and 4 were not cytotoxic at the highest concentrationtested (75 mmol/L), suggesting that elongation of the chain length at the 28-position in both betulinic acid (1) and betulonic acid (2)was detrimental to the cytotoxicity.The acylation products 28-O-bromoacetates (8a, 8b and 11) and 28-O-methoxyacetate 13exhibited cytotoxicity against several cancer cell lines tested.
Synthesis of novel 3,5-disubstituted-dihydroisoxazoles from methyl undec-10-enoate and isoxazoles, triazole and tetrazolo-triazole from methyl undec-10-ynoate
Shweta Sharma , Abdul Rauf
2009, 20(10): 1145-1149  doi: 10.1016/j.cclet.2009.04.032
[Abstract](157) [FullText HTML] [PDF 324KB](0)
Abstract:
The efficient cycloaddition reactions were carried out to afford the novel 3,5-disubstituted-dihydroisoxazoles from methyl undec-10-enoate and isoxazoles, triazole and tetrazolo-triazole from methyl undec-10-ynoate.The reactions occurred under relatively mild conditions and afforded the desired products in good yields.
Synthesis of 1,1'-binaphthyl-2,2'-diamine from 2-naphthol under atmospheric pressure
Qiang Feng , Chao Zhang , Qiang Tang , Mei Ming Luo
2009, 20(10): 1150-1152  doi: 10.1016/j.cclet.2009.05.033
[Abstract](164) [FullText HTML] [PDF 218KB](3)
Abstract:
A practical protocol to obtain 1,1'-binaphthyl-2,2'-diamine was developed from 2-naphthol and 2-naphthylhydrazine under mild conditions:solvent-free, 125-130℃, atmospheric pressure.The convenient procedure makes the process amenable for large-scale synthesis of the versatile compound.
New optically active poly(amide-imide)s derived from N,N'-(4,4-diphthaloyl)-bis-L-leucine and hydantoin derivatives:Synthesis and properties
Khalil Faghihi
2009, 20(10): 1153-1156  doi: 10.1016/j.cclet.2009.06.001
[Abstract](166) [FullText HTML] [PDF 288KB](0)
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Six new optically active poly(amide-imide)s (5a-f) were synthesized through the direct polycondensation reaction of N,N'-(4,4'-diphthaloyl)-bis-L-leucine (3) with six hydantoin derivatives (4a-f).Triphenyl phosphite (TPP)/pyridine in the presence of calcium chloride (CaCl 2) and N-methyl-2-pyrrolidone (NMP) were successfully applied for direct polycondensation.The polycondensation reactions produce a series of new poly(amide-imide)s (5a-f) in high yields, and inherent viscosity between 0.42 and 0.55 dL/g.The resulting poly(amide-imide)s (5a-f) were characterized by elemental analysis, viscosity measurements, thermal gravimetric analysis (TGA and DTG), solubility test and FT-IR spectroscopy.
Selective debenzylation of benzyl esters by silica-supported sodium hydrogen sulphate
Yan Wei Hu , Li Zuo , De Yong Ye , Wen Hu Duan
2009, 20(10): 1157-1160  doi: 10.1016/j.cclet.2009.04.028
[Abstract](166) [FullText HTML] [PDF 565KB](0)
Abstract:
A new debenzylation of benzyl esters by silica-supported sodium hydrogen sulfate is described.The debenzylation could be achieved selectively and efficiently in good to excellent yields without affecting sensitive functional groups such as nitro,unsaturated bonds, and ethyl ester.
Preparation of nucleoside-pyridine hybrids and pyridine attached acylureas from an unexpected uracil ring-opening and pyridine ring-forming sequence
Xue Sen Fan Xia Wang , Xin Ying Zhang , Dong Feng , Ying Ying Qu
2009, 20(10): 1161-1165  doi: 10.1016/j.cclet.2009.04.014
[Abstract](179) [FullText HTML] [PDF 302KB](0)
Abstract:
Novel pyrimidine nucleoside-3,5-dicyanopyridine hybrids (4) or pyridine attached acylureas (5) were selectively and efficiently prepared from the reaction of 2'-deoxyuridin-5-yl-methylene malononitrile (1), malononitrile (2) and thiophenol (3) or from an unexpected uracil ring-opening and pyridine ring-forming sequence via the reaction of 1 and 3.It is the first time such a sequence has ever been reported.
Clean synthesis of calix[4]crown-5-sulfonyl cyclothiourea derivatives at room temperature in aqueous solution
Cong Wen Ding , Ming Jie Zhang Ning Ma
2009, 20(10): 1166-1168  doi: 10.1016/j.cclet.2009.04.031
[Abstract](164) [FullText HTML] [PDF 234KB](0)
Abstract:
Calix[4]-crown-5-sulfonyl cyclothiourea derivatives 6 and 7 were synthesized from calix[4]-crown-5-monosulfonylethylenediamine derivatives 4 and 5 and carbon disulfide through nucleophilic addition and subsequent cyclization of intramolecule at room temperature in aqueous solution.The advantages of the novel protocol are the mild reaction condition, free organic solvent, simple final treatment, easy isolation of products and excellent yields.
Copper-catalyzed synthesis of phenols from aryl halides and 4-methoxylbenzyl alcohol
Chuan Zhou Tao , Wei Wei Liu , Ji You Sun
2009, 20(10): 1170-1174  doi: 10.1016/j.cclet.2009.06.004
[Abstract](165) [FullText HTML] [PDF 767KB](0)
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A catalytic method was developed to synthesize substituted phenols from the corresponding aryl bromides and chlorides under mild conditions (yields=34-92%).4-Methoxylbenzyl alcohol was used as water surrogate and CuI/3,4,7,8-tetramethyl-1,10-phenanthroline was used as catalyst to achieve the C-O cross-coupling.
An efficient method for synthesis of organophosphorus compounds in aqueous media
Reza Heydari Malek Taher Maghsoodlou , Razieh Nejat Yami
2009, 20(10): 1175-1178  doi: 10.1016/j.cclet.2009.05.019
[Abstract](162) [FullText HTML] [PDF 406KB](0)
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A convenient and facile one-pot synthesis of stable phosphorus ylides and 1,4-diionic organophosphorus compounds is reported by the reaction of triphenylphosphine, dialkylacetylenedicarboxylates and N-H, C-H or S-H acids in the presence of polyethyleneglycol (PEG), b-cyclodextrin (β-CD), glycerine (Gly) or ethyleneglycol (EG) in water.This methodology is of interest due to the use of water as a solvent, thus minimizing the cost operational hazards, and environmental pollution.
Design, synthesis and antiproliferative activity of novel 2,7-disubstituted triazolo[1,5-a]pyrimidines
Xin Zhai , Nan Jiang , Ke Liang Zhang , Feng Bao , Ping Gong
2009, 20(10): 1179-1182  doi: 10.1016/j.cclet.2009.04.027
[Abstract](159) [FullText HTML] [PDF 513KB](0)
Abstract:
In our efforts to identify novel potent anticancer agents, we synthesized a series of 2,7-disubstituted triazolo[1,5-a]pyrimidines (6-16).Their antiproliferative activity against Bel-7402, HT-1080 and WI-38 cell lines was tested by MTTassay in vitro.Four of the compounds (9-11 and 16) displayed promising antiproliferative activity superior to gefitinib, especially compound 9.A preliminary SAR study of these derivatives was performed.
Oxidation of 3,4-dihydropyrimidin-2(1H)-ones with nitrosonium (NO+)
Rui Rui Liang , Guai Li Wu , Wen Tao Wu , Long Min Wu
2009, 20(10): 1183-1186  doi: 10.1016/j.cclet.2009.04.039
[Abstract](164) [FullText HTML] [PDF 290KB](1)
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3,4-Dihydropyrimidin-2(1H)-ones (DHPMs) were oxidized with 1.2 equiv.of nitrosonium tetrafluoroborate (NO+BF4-) topyrimidin-2(1H)-ones in acetonitrile at room temperature in high yields.
Evaluation of lipid peroxidation inhibition and free radical scavenging abilities of 5,6,7-trimethoxy dihydroflavonols
Ke Xin Huang , Yu Bing Feng , Wei Yao , Lei Xiang Yang , Feng Wang , Hai Bo Li , Su Zeng , Jing Xu Gong , Ming Hui Hu , Yu Zhao , Xiu Mei Wu , Xiao Kun Li , Jia Qu
2009, 20(10): 1187-1190  doi: 10.1016/j.cclet.2009.04.026
[Abstract](157) [FullText HTML] [PDF 371KB](0)
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Four naturally rare 5,6,7-trimethoxy-2,3-cis-dihydroflavonols (3-6) and two 5,6,7-trimethoxy-2,3-trans-dihydroflavonols (7-8)were designed and synthesized.Their antioxidative properties were evaluated by way of examining their scavenging capacities towards DPPH and O2·-.free radicals, as well as by measuring their inhibitory ability against LPO.Both the 2,3-trans and the 2,3-cis conformers exhibited certain quenching abilities to DPPH and O2·- radicals, while most of the synthetic dihydroflavonols demonstrated remarkable inhibition to LPO.
A fluorescent probe for fluoride ion based on 2-aminopyridyl-bridged calix[6]arene
ian Hang Mai , Jun Min Liu , Shao Yong Li , Huan Feng Jiang
2009, 20(10): 1191-1194  doi: 10.1016/j.cclet.2009.05.002
[Abstract](171) [FullText HTML] [PDF 460KB](0)
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An 2-aminopyridyl-bridged calix[6]arene on the upper rim fixed in cone conformation (3) was successfully synthesized and its highly selective recognition towards fluoride ion was proved by fluorescent and 1H NMR titration experiments.
Synthesis of bacillamide 3 and its analogue
Duo Li , Hai Shen Yang , Qing Cui , Shen Jie Mao , Xiao Hua Xu
2009, 20(10): 1195-1197  doi: 10.1016/j.cclet.2009.05.014
[Abstract](164) [FullText HTML] [PDF 218KB](0)
Abstract:
The bacillamide 1 is a new algaecide from the marine bacterium Bacillus sp.SY-1.Its analogues bacillamide 3 and alkaloid 4 were firstly synthesized effectively from D-alanine.The key step was a coupling reaction via the mixed anhydride.All structures were confirmed by 1H NMR and 13C NMR.The final compounds were confirmed by 1HNMR,13C NMR and HRMS and the results are consistent with the reported natural products.
Solvent-free and catalyst-free method for the synthesis of 2,4,5-triarylimidazoles under microwave irradiation
Jian Feng Zhou , Gui Xia Gong , Hui Qin Zhu , Feng Xia Zhu
2009, 20(10): 1198-1200  doi: 10.1016/j.cclet.2009.05.027
[Abstract](165) [FullText HTML] [PDF 199KB](0)
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A facile procedure for the synthesis of 2,4,5-triarylimidazoles is being reported starting from benzil, aromatic aldehyde and ammonium acetate.The reactions were carried out with catalyst-free, solvent-free and under microwave irradiation conditions in high yield (80-99%) with short time (3-5 min) and environmental benign, as well as convenient operation.The structures of the compounds have been confirmed on the basis of their IR,1H NMR, and/or 13C NMR, MS, and elemental analyzer.
The simple synthesis of quinazoline-2,4-dione derivatives using Boc strategy
Xu Qin Li
2009, 20(10): 1201-1202  doi: 10.1016/j.cclet.2009.05.001
[Abstract](168) [FullText HTML] [PDF 250KB](0)
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Quinazolinediones are particularly attractive pharmacophores because of their wide range of bioactivities.A convenient synthetic pathway to three-substituted quinazoline-2,4-dione derivatives was developed from substituted anthranilamide via carbonylation with Boc anhydride and then cyclization in the presence of the base sodium methoxide.Good to excellent yields have been achieved.
An improved synthesis of (-)-7-isopropyl-cis-1-amino-2-indanol the chiral auxiliary for 6π-azaelectrocyclization
Su Yun Liu , Shigeo Katsumura
2009, 20(10): 1204-1206  doi: 10.1016/j.cclet.2009.05.024
[Abstract](163) [FullText HTML] [PDF 247KB](0)
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(-)-7-Isopropyl-cis-1-amino-2-indanol, a key chiral auxiliary and ligand in the highly stereo-selective asymmetric 6π-azaelectrocyclization,has been prepared previously by two methods.Each however involved using of one extreme condition,i.e.high temperature or high pressure, for the respective reaction.A modified reaction route employed mild condition for synthesis was presented in this report.
A new triterpenoid saponin from the leaves and stems of Panax quinquefolium L.
Guo Yu Li , Yi Mei Zeng , He Meng , Xian Li , Jin Hui Wang
2009, 20(10): 1207-1210  doi: 10.1016/j.cclet.2009.05.017
[Abstract](168) [FullText HTML] [PDF 253KB](0)
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One new triterpenoid saponin, quinquenoside L 17 (1), was isolated from the leaves and stems of Panax quinquefolium L., and its structure was elucidated as 20-O-[(β-D-xylopyranosyl-(1-6)-O-β-D-glucopyranosyl)]-6-O-β-D-glucopyranosyl-dammar-24-ene3,6,12,20-tetraol, by the combination analysis of one-dimensional NMR and two-dimensional NMR, mass spectrometry, CD spectrum and chemical evidences.
Two new eudesmane sesquiterpenes from Lactuca sativa var.anagustata L
Yi Feng Han Gui Xiu Cao , Min Xia
2009, 20(10): 1211-1214  doi: 10.1016/j.cclet.2009.06.002
[Abstract](163) [FullText HTML] [PDF 236KB](0)
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Two new eudesmane sesquiterpene lactones were isolated from the stalk of Lactuca sativa var.anagustata L and their structures were elucidated by means of spectroscopic methods, including 2D NMR (1H-1H COSY, HMBC and NOESY) as 1β-O-β-Dglucopyranosyl-4a-hydroxyl-5a, 6β, 11βH-eudesma-12, 6α-olide (1) and 1β-hydroxyl-15-O-(-methoxyphenylacetyl)-5a, 6β,11bH-eudesma-3-en-12, 6a-olide (2).
Minor antifungal aromatic glycosides from the roots of Gentiana rigescens (Gentianaceae)
Min Xu , Chong Ren Yang , Ying Jun Zhang
2009, 20(10): 1215-1217  doi: 10.1016/j.cclet.2009.05.006
[Abstract](165) [FullText HTML] [PDF 214KB](0)
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Two new phenolic glycosides, 2,3-dihydroxybenzoic acid methyl ester 3-O-β-D-glucopyranosyl-(1-6)-β-D-glucopyranoside (1)and 2,5-dihydroxylbenzofuran 5-O-β-D-xylopyranosyl-(1-6)-O-β-D-glucopyranoside (2), were isolated as the minor chemical constituents from the roots of Gentiana rigescens, along with 15 known compounds.Their structures were elucidated by detailed spectroscopic analysis, including 1D, 2D NMR and chemical method.All of these compounds were isolated for the first time from the title plant.Moreover, compounds 1 and 2 were tested for the antifungal activities on three plant pathogens Peronophythora litchi,Glomerella cingulata, and Glorosprium musarum
Alkaloid from Dicranostigma leptopodum (Maxim) Fedde
Yan Dang , Hong Fei Gong , Jun Xi Liu , Si Jiu Yu
2009, 20(10): 1218-1220  doi: 10.1016/j.cclet.2009.05.020
[Abstract](165) [FullText HTML] [PDF 194KB](0)
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Phytochemical investigation of the whole plants of Dicranostigma leptopodum (Maxim) Fedde has lead to the isolation of five alkaloids:dicranostigmine (1), isocorydine (2), corydine (3), protopine (4) and sinoacutine (5).Oxomorphine alkaloid (5) was isolated from the genus Dicranostigma for the first time and the new compound structure (1) was elucidated by various spectroscopic methods including 2D NMR techniques (gCOSY, HMQC, HMBC and NOESY) and HRESI-MS.
A new monoterpenoid indole alkaloid from Rauvolfia yunnanensis
Bao Hui Cheng , Jian Chao Chen , Jun Xi Liu
2009, 20(10): 1221-1223  doi: 10.1016/j.cclet.2009.05.032
[Abstract](170) [FullText HTML] [PDF 222KB](0)
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One new monoterpenoid indole alkaloid, 11-methoxyburnamine-17-O-3',4',5'-trimethoxybenzoate (1), was isolated from Rauvolfia yunnanensis Tsiang.Its structure was identified by spectroscopic evidences.
Two new 24-hydroxylated asterosaponins from Culcita novaeguineae
Xiao Guang Ma , Hai Feng Tang , Chang Hai Zhao , Ning Ma , Min Na Yao , Ai Dong Wen
2009, 20(10): 1227-1230  doi: 10.1016/j.cclet.2009.05.031
[Abstract](156) [FullText HTML] [PDF 231KB](0)
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Two new 24-hydroxylated asterosaponins, sodium (20R,24S)-6α-O-(4-O-sodiumsulfato-β-D-quinovopyranosyl)-5a-cholest9(11)-en-3b,24-diol 3-sulfate (1) and sodium (20R,24S)-6α-O-[3-O-methyl-b-D-quinovopyranosyl-(1→2)-β-D-xylopyranosyl(1→3)-β-D-glucopyranosyl]-5a-cholest-9(11)-en-3β,24-diol 3-sulfate (2), were isolated from the starfish Culcita novaeguineae.Their structures were elucidated by extensive spectral analysis and chemical evidences.
A new polyhydroxysteroidal glycoside from the starfish Anthenea chinensis
Ning Ma , Hai Feng Tang , Feng Qiu , Hou Wen Lin , Xiang Rong Tian , Wei Zhang
2009, 20(10): 1231-1234  doi: 10.1016/j.cclet.2009.05.012
[Abstract](163) [FullText HTML] [PDF 245KB](0)
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A new polyhydroxysteroidal glycoside, (20R,24R)-16-O-(4-O-methyl-2-acetamido-2-deoxy-β-D-galactopyranosyl)-24-ethyl5a-cholest-8(14)-en-3β,6β,7β,16α-tetrol (anthenoside A, 1), was isolated from the starfish Anthenea chinensis.Its structure was elucidated by extensive spectral analysis and chemical evidences.1 exhibited significant cytotoxicity against human tumor K-562,BEL-7402 and U87MG cells.
Determination of sulfur anions by ion chromatography-postcolumn derivation and UV detection
Mei Lan Chen , Ming Li Ye , Xue Ling Zeng , Yun Chang Fan , Zhu Yan
2009, 20(10): 1241-1244  doi: 10.1016/j.cclet.2009.05.003
[Abstract](154) [FullText HTML] [PDF 224KB](0)
Abstract:
A novel method for determination of formaldehyde sulfoxylate, sulfite, thiocyanate, and thiosulfate in foodstuffs by ion chromatography separation with postcolumn derivation and UV detection has been developed.All species are separated at Dionex IonPac AG22A and AS22Awith mobile phase of a mixture of 4.5 mmol/L sodium carbonate and 0.8 mmol/L sodium bicarbonate at a flow-rate of 1.0 mL/min.The postcolumn derivation solution was 0.24% iodine in 0.2% phosphate acid and the detection wavelength was set at 288 nm.The detection limits (LOD, signal-to-noise ratio of 3) of formaldehyde sulfoxylate, sulfite,thiocyanate, and thiosulfate were 0.004, 0.006, 0.006, and 0.007 mg/L, respectively.Within-day relative standard deviations (RSD,n=10) of formaldehyde sulfoxylate, sulfite, thiocyanate, and thiosulfate were 3.24%, 3.76%, 2.68%, and 2.07%, respectively.The recoveries of the four anions were in the range of 67.2-116.5%.
Copper modified platinum electrode for amperometric detection of spectinomycin sulfate by anion-exchange chromatography
Ling Ling Xi Pei Min Zhang , Yan Zhu
2009, 20(10): 1245-1247  doi: 10.1016/j.cclet.2009.04.025
[Abstract](171) [FullText HTML] [PDF 186KB](0)
Abstract:
A La3+-Cu/Pt modified electrode was fabricated by electrodepositing process in CuSO 4 solution by adding a small amount oflanthium compound, and it was employed for direct current (DC) amperometric detection of spectinomycin by anion-exchange chromatography.Without derivatization, this method can simultaneously determine the main component and impurities in spectinomycin pharmaceutical raw material.Ease of preparation, being applied in DC detection mode and good catalytic stability confirmed the interests of this modified electrode as amperometric sensor for the determination of spectinomycin.
Novel estradiol sensors based on carbon nanotube multilayer modified gold hair microelectrodes
Jun Hui Xu , Cheng Guo Hu , Sheng Shui Hu
2009, 20(10): 1248-1250  doi: 10.1016/j.cclet.2009.04.019
[Abstract](159) [FullText HTML] [PDF 1344KB](0)
Abstract:
Multi-walled carbon nanotube multilayers were modified onto a newly proposed gold hair microelectrode via a simple layer-bylayer assembling method.The resulting electrode showed a sensitive oxidation response to estradiol with detection limit as low as 1.0×10-8mol/L, foreseeing a promising approach to the fabrication of high-sensitive microsensors.
New type flooding systems in enhanced oil recovery
Xin Ping Li , Li Yu Yong Qiang Ji , Bo Wu Gan Zuo Li , Li Qiang Zheng
2009, 20(10): 1251-1254  doi: 10.1016/j.cclet.2009.05.007
[Abstract](172) [FullText HTML] [PDF 335KB](0)
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Wormlike micelles, obtained in anionic surfactant sodium oleate (NaOA) solutions in the presence of sodium phosphate (Na 3 PO 4), were studied using the steady and dynamic rheological methods.The laboratory simulation flooding experiments were used to investigate the effects of flooding for the wormlike micelles system.The results show that the oil recovery is 32.7%.This flooding system is a new type and has high activity with a low cost.
Electrochemical performance of sulfur composite cathode materials for rechargeable lithium batteries
Feng Wu , Sheng Xian Wu , Ren Jie Chen , Shi Chen , Guo Qing Wang
2009, 20(10): 1255-1258  doi: 10.1016/j.cclet.2009.04.036
[Abstract](169) [FullText HTML] [PDF 294KB](0)
Abstract:
The structure and characteristic of carbon materials have a direct influence on the electrochemical performance of sulfur-carbon composite eleceof elemental sulfur and activated carbon, which is characterized as high specific surface area and microporous structure.The composite, contained 70% sulfur, as cathode in a lithium cell based on organic liquid electrolyte was tested at room temperature.It showed two reduction peaks at 2.05 V and 2.35 V, one oxidation peak at 2.4 V during cyclic voltammogram test.The initial discharge specific capacity was 1180.8 mAh g -1 and the utilization of electrochemically active sulfur was about 70.6% assuming a complete reaction to the product of Li 2S.The specific capacity still kept as high as 720.4 mAh g-1after 60 cycles retaining 61% of the initial discharge capacity.
Highly stable supramolecular hydrogels formed from 1,3,5-benzenetricarboxylic acid and hydroxyl pyridines
Li Ming Tang Yu Jiang Wang
2009, 20(10): 1259-1262  doi: 10.1016/j.cclet.2009.04.030
[Abstract](181) [FullText HTML] [PDF 2452KB](0)
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New supramolecular hydrogels with the maximal sol-gel transition temperature (Tgel) of 95℃ were obtained by using gelators formed from 1,3,5-benzenetricarboxylic acid (BTA) and para-hydroxyl pyridine (PHP) or meta-hydroxyl pyridine (MHP).Thesingle crystal structure of the complex formed from BTA and ortho-hydroxyl pyridine (OHP) indicated that the molecules assembled into superstructure via both hydrogen bonds and π-πstacking interaction.
Molecular modeling of epsilon RNA from hepatitis B virus
Huai Ren Pan , Hai Jun Zhu , Zhong Rong Song , Xu Dong Zhang , Huai Cao
2009, 20(10): 1263-1266  doi: 10.1016/j.cclet.2009.05.018
[Abstract](160) [FullText HTML] [PDF 1677KB](0)
Abstract:
An initial model of the HBV epsilon RNA was built by the Biopolymer module of Insight Ⅱ.While its three-dimensional structure was obtained through structure optimization based on molecular dynamics simulation, the two active sites were found.A comparison with the experimental result indicated that the active sites may be the binding sites of the epsilon RNA in the RT-epsilon interaction.The result will be helpful to further discussion about the mechanism of RT-epsilon interaction and the study of HBV genome replication.
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