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2011 Volume 22 Issue 7
2011, 22(7): 671-764
doi: 10.1016/j.cclet.2011.01.026
Abstract:
(-)-Clausenamide is a drug candidate under Phase I clinical trial for treatment of Alzheimer's disease (AD). In order to elucidate the substituent related structure-activity relationship, six one-substituent modified (-)-clausenamide analogues were designed, and four of them, namely 3-0-methyl, 6-0-methyl, 3-des-hydroxyl and 6-des-hydroxyl analogues were prepared by selective 3- and 6- OH modification of (-)-clausenamide.
(-)-Clausenamide is a drug candidate under Phase I clinical trial for treatment of Alzheimer's disease (AD). In order to elucidate the substituent related structure-activity relationship, six one-substituent modified (-)-clausenamide analogues were designed, and four of them, namely 3-0-methyl, 6-0-methyl, 3-des-hydroxyl and 6-des-hydroxyl analogues were prepared by selective 3- and 6- OH modification of (-)-clausenamide.
2011, 22(7): 757-760
doi: 10.1016/j.cclet.2010.12.043
Abstract:
Eight 16,17-pyrazo-annulated steroidal derivatives were synthesized and evaluated in vitro vascular endothelial growth factor (VEGF) inhibitory activity with 2-methoxyestradiol (2-ME) as the reference compound. Most of the compounds showed potent VEGF inhibitory activity with EC50 values of micromolar or submicromolar range. Among them, the compounds 3 and 8 exhibited similar EC50 values and obviously better TI values compared with 2-ME.
Eight 16,17-pyrazo-annulated steroidal derivatives were synthesized and evaluated in vitro vascular endothelial growth factor (VEGF) inhibitory activity with 2-methoxyestradiol (2-ME) as the reference compound. Most of the compounds showed potent VEGF inhibitory activity with EC50 values of micromolar or submicromolar range. Among them, the compounds 3 and 8 exhibited similar EC50 values and obviously better TI values compared with 2-ME.
2011, 22(7): 765-767
doi: 10.1016/j.cclet.2011.01.007
Abstract:
A practical chemical synthesis of L-carnitine (1) has been accomplished from (R)-3-chloro-l,2-propanediol ((R)-4), which is a main by-product originated from (R,R)-Salen Co(Ⅲ) catalyzed hydrolytic kinetic resolution (HKR) of (±)-epichlorohydrin (R)-4 was utilized as a chiral starting material to prepare the key intermediate cyclic sulfite ((R)-5). The new synthetic approach demonstrated an efficient utilization of organic by-product for the asymmetric synthesis of bioactive compounds.
A practical chemical synthesis of L-carnitine (1) has been accomplished from (R)-3-chloro-l,2-propanediol ((R)-4), which is a main by-product originated from (R,R)-Salen Co(Ⅲ) catalyzed hydrolytic kinetic resolution (HKR) of (±)-epichlorohydrin (R)-4 was utilized as a chiral starting material to prepare the key intermediate cyclic sulfite ((R)-5). The new synthetic approach demonstrated an efficient utilization of organic by-product for the asymmetric synthesis of bioactive compounds.
2011, 22(7): 768-770
doi: 10.1016/j.cclet.2010.12.037
Abstract:
To search for more potent antitumor agent, a series of novel nitric oxide-donating colchicine (Col) derivatives (6a-f, 8a and b) were synthesized by coupling nitrates with N-methyl colchiceinamide. Their cytotoxicity against four human cancer cell lines in vitro were evaluated by MTT assay. It was found that many of the derivatives displayed significant activity, particularly, compounds 6c, 8a and 8b showed more potent cytotoxic activities than Col.
To search for more potent antitumor agent, a series of novel nitric oxide-donating colchicine (Col) derivatives (6a-f, 8a and b) were synthesized by coupling nitrates with N-methyl colchiceinamide. Their cytotoxicity against four human cancer cell lines in vitro were evaluated by MTT assay. It was found that many of the derivatives displayed significant activity, particularly, compounds 6c, 8a and 8b showed more potent cytotoxic activities than Col.
2011, 22(7): 771-773
doi: 10.1016/j.cclet.2011.01.005
Abstract:
The reactive intermediate generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylate was trapped by 6-quinolinol to produce highlyfunctionalized 4H-chromenes in fairly good yields.
The reactive intermediate generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylate was trapped by 6-quinolinol to produce highlyfunctionalized 4H-chromenes in fairly good yields.
2011, 22(7): 774-776
doi: 10.1016/j.cclet.2011.01.009
Abstract:
A short synthesis of the tricyclic 6–6–6 and 6–7–6 ring systems of the abietane- and icetexane-type diterpenoids from a common intermediate is presented, using alkylation and acid-catalyzed cyclization as key steps.
A short synthesis of the tricyclic 6–6–6 and 6–7–6 ring systems of the abietane- and icetexane-type diterpenoids from a common intermediate is presented, using alkylation and acid-catalyzed cyclization as key steps.
2011, 22(7): 777-780
doi: 10.1016/j.cclet.2011.01.002
Abstract:
A mild, efficient and high yielding protocol for the synthesis of 2,2'-arylmethelene dicyclohexane-1,3-dione derivatives at room temperature and 9-aryl-l,8-dihydrooctahydroxanthene at conventional heating using cesium fluoride as a catalyst is reported. The major advantages of this reaction are excellent yield, very short reaction time and use of inexpensive catalyst.
A mild, efficient and high yielding protocol for the synthesis of 2,2'-arylmethelene dicyclohexane-1,3-dione derivatives at room temperature and 9-aryl-l,8-dihydrooctahydroxanthene at conventional heating using cesium fluoride as a catalyst is reported. The major advantages of this reaction are excellent yield, very short reaction time and use of inexpensive catalyst.
2011, 22(7): 781-784
doi: 10.1016/j.cclet.2011.01.015
Abstract:
A series of Andro derivatives were described and evaluated for their anti-HIV activity in vitro. Compound 10 and 16b, of which TI were > 10, had some anti-HTV-1 activity in vitro. Therein, compound 10 which was the best potent compound, could serve as a new lead for further development of anti-AIDS agents.
A series of Andro derivatives were described and evaluated for their anti-HIV activity in vitro. Compound 10 and 16b, of which TI were > 10, had some anti-HTV-1 activity in vitro. Therein, compound 10 which was the best potent compound, could serve as a new lead for further development of anti-AIDS agents.
2011, 22(7): 785-788
doi: 10.1016/j.cclet.2010.12.020
Abstract:
A powerful approach to the synthesis of an unprecedented polynorbornene with pendant moiety bearing azide and terminal alkyne groups is developed. Two key intermediates, namely, 3-azido-5-(2-(trimethylsilyl)ethynyl) benzyl alcohol and 4-(4-aza-tricyclo [5.2.1.02.6]dec-8-en-4-yl) benzoic acid, were optimally synthesized for convergent synthesis of the corresponding monomer.
A powerful approach to the synthesis of an unprecedented polynorbornene with pendant moiety bearing azide and terminal alkyne groups is developed. Two key intermediates, namely, 3-azido-5-(2-(trimethylsilyl)ethynyl) benzyl alcohol and 4-(4-aza-tricyclo [5.2.1.02.6]dec-8-en-4-yl) benzoic acid, were optimally synthesized for convergent synthesis of the corresponding monomer.
2011, 22(7): 789-792
doi: 10.1016/j.cclet.2011.01.003
Abstract:
A facile, efficient synthesis of 3-(guaiazulen-l-yl)succinimides was developed by Michael-type addition of guaiazulene to maleimides in the presence of p-toluenesulfonic acid under mild reaction conditions.
A facile, efficient synthesis of 3-(guaiazulen-l-yl)succinimides was developed by Michael-type addition of guaiazulene to maleimides in the presence of p-toluenesulfonic acid under mild reaction conditions.
2011, 22(7): 793-796
doi: 10.1016/j.cclet.2011.01.017
Abstract:
Various 2-phenylimidazo [4,5-f] [1,10] phenanthrolines were synthesized from potassium ferro-cyanide trihydrate (KFCT) complex catalyzed three component reaction of 1,10-phenanthroline-5,6-dione, aromatic aldehydes and ammonium acetate at room temperature in excellent isolated yield. This is a simple and straight forward, high yielding, not involving any hazardous or expensive catalyst method.
Various 2-phenylimidazo [4,5-f] [1,10] phenanthrolines were synthesized from potassium ferro-cyanide trihydrate (KFCT) complex catalyzed three component reaction of 1,10-phenanthroline-5,6-dione, aromatic aldehydes and ammonium acetate at room temperature in excellent isolated yield. This is a simple and straight forward, high yielding, not involving any hazardous or expensive catalyst method.
2011, 22(7): 797-800
doi: 10.1016/j.cclet.2010.12.046
Abstract:
Commercially available guanidine hydrochloride (GuHCl) has been found to be a highly efficient catalyst for the Mannich reaction. β-Amino carbonyl compounds were obtained in reasonable yields when the Mannich reaction was carried out at room temperature under solvent-free conditions.
Commercially available guanidine hydrochloride (GuHCl) has been found to be a highly efficient catalyst for the Mannich reaction. β-Amino carbonyl compounds were obtained in reasonable yields when the Mannich reaction was carried out at room temperature under solvent-free conditions.
2011, 22(7): 801-803
doi: 10.1016/j.cclet.2010.11.036
Abstract:
Facile synthesis of the two new natural heterocyclic compounds bretschneiderazines A (2) and B (3), isolated from an extract of the stems of Bretschneidera sinensis, is reported. We employed the cyclization reaction of benzamide by directed lithiation and sequential treatment with sulfur and phosgene as key steps. All new compounds have been fully characterized by means of IR, 1H NMR, 13C NMR, and HRMS.
Facile synthesis of the two new natural heterocyclic compounds bretschneiderazines A (2) and B (3), isolated from an extract of the stems of Bretschneidera sinensis, is reported. We employed the cyclization reaction of benzamide by directed lithiation and sequential treatment with sulfur and phosgene as key steps. All new compounds have been fully characterized by means of IR, 1H NMR, 13C NMR, and HRMS.
2011, 22(7): 804-806
doi: 10.1016/j.cclet.2011.01.018
Abstract:
To further expand an effective modified route for the shift from an antibacterial fluoroquinolone (FQ) to an antitumor FQ, two series of title compounds based on an isostere of the FQ C3 carboxylic group with two fused heterocyclic rings, [l,2,4]triazolo[3,4-b][l,3,4]thiadiazine and pyrazolo[5,l-c][l,2,4]triazole, respectively, were designed and synthesized starting from the current antibacterial FQs, and their in vitro antitumor activity against L1210, CHO cell lines were evaluated via their respective IC50 values.
To further expand an effective modified route for the shift from an antibacterial fluoroquinolone (FQ) to an antitumor FQ, two series of title compounds based on an isostere of the FQ C3 carboxylic group with two fused heterocyclic rings, [l,2,4]triazolo[3,4-b][l,3,4]thiadiazine and pyrazolo[5,l-c][l,2,4]triazole, respectively, were designed and synthesized starting from the current antibacterial FQs, and their in vitro antitumor activity against L1210, CHO cell lines were evaluated via their respective IC50 values.
2011, 22(7): 807-810
doi: 10.1016/j.cclet.2010.12.051
Abstract:
Silica gel-supported polyphosphoric acid (PPA-SiO2) was found to be an efficient catalyst for the one-pot four-component Hantzsch condensation reaction of aryl aldehydes, dimedone, ethyl acetoacetate and ammonium acetate to afford the corresponding polyhydroquinoline derivatives in high yields. The main advantages of the present approach are short reaction times, clean reaction profiles, simple experimental and workup procedures.
Silica gel-supported polyphosphoric acid (PPA-SiO2) was found to be an efficient catalyst for the one-pot four-component Hantzsch condensation reaction of aryl aldehydes, dimedone, ethyl acetoacetate and ammonium acetate to afford the corresponding polyhydroquinoline derivatives in high yields. The main advantages of the present approach are short reaction times, clean reaction profiles, simple experimental and workup procedures.
2011, 22(7): 811-814
doi: 10.1016/j.cclet.2011.01.020
Abstract:
An environmentally friendly procedure for the preparation of 10-aryl-6,8-dimethyl-6,10-dihydro-5-oxa-6,8-diazaanthra[2,3-d] [1,3]dioxole-7,9-diones under thermal solvent-free conditions in the presence of cyanuric chloride as heterogeneous catalyst was developed.
An environmentally friendly procedure for the preparation of 10-aryl-6,8-dimethyl-6,10-dihydro-5-oxa-6,8-diazaanthra[2,3-d] [1,3]dioxole-7,9-diones under thermal solvent-free conditions in the presence of cyanuric chloride as heterogeneous catalyst was developed.
2011, 22(7): 815-818
doi: 10.1016/j.cclet.2011.01.008
Abstract:
A simple and convenient procedure for the synthesis of nitriles by dehydration of aldoxime using supported sulphuric acid on melamine-formaldehyde resin (MFR) under solvent-free condition has been developed. A variety of aromatic and aliphatic aldoximes were converted to the corresponding nitriles. The resin was recovered and reused for subsequent reactions.
A simple and convenient procedure for the synthesis of nitriles by dehydration of aldoxime using supported sulphuric acid on melamine-formaldehyde resin (MFR) under solvent-free condition has been developed. A variety of aromatic and aliphatic aldoximes were converted to the corresponding nitriles. The resin was recovered and reused for subsequent reactions.
2011, 22(7): 819-822
doi: 10.1016/j.cclet.2010.12.054
Abstract:
A novel large thiophene-fused polycyclic aromatics 1 based on pyrene 5 has been synthesized, and its structure was confirmed by 1H NMR, 13>C NMR, MS, UV–vis and elemental analysis. The key steps of the synthesis involved the Stille cross-coupling reaction and followed by selective β-β oxidative cyclization of pendant thienyl rings by FeCl3 under mild conditions.
A novel large thiophene-fused polycyclic aromatics 1 based on pyrene 5 has been synthesized, and its structure was confirmed by 1H NMR, 13>C NMR, MS, UV–vis and elemental analysis. The key steps of the synthesis involved the Stille cross-coupling reaction and followed by selective β-β oxidative cyclization of pendant thienyl rings by FeCl3 under mild conditions.
2011, 22(7): 823-826
doi: 10.1016/j.cclet.2010.12.055
Abstract:
In this work it was presented an application of task specific onium salt as soluble support for the synthesis of 3-amino-5-ary 1-2,5-dihydropyridazines. This soluble support is of wide applicability and combines advantages of solid phase synthesis without its limitations with those of solution phase chemistry. After a simple washing step, products were cleaved from the supports and obtained in good yields.
In this work it was presented an application of task specific onium salt as soluble support for the synthesis of 3-amino-5-ary 1-2,5-dihydropyridazines. This soluble support is of wide applicability and combines advantages of solid phase synthesis without its limitations with those of solution phase chemistry. After a simple washing step, products were cleaved from the supports and obtained in good yields.
2011, 22(7): 827-830
doi: 10.1016/j.cclet.2011.01.021
Abstract:
Melamine and poly vinylpyrrolidone (PVP) reacted with neat sulfuric acid readily to form two new organic solid acids namely melamine-(H2SO4)3 and PVP-(H2SO4)n· These solid acids were used for the first nitration of bisphenol A as well as other phenols in the presence of NH4NO3. Mono- and di-nitro bisphenol A have been characterized with IR and 1H NMR techniques.
Melamine and poly vinylpyrrolidone (PVP) reacted with neat sulfuric acid readily to form two new organic solid acids namely melamine-(H2SO4)3 and PVP-(H2SO4)n· These solid acids were used for the first nitration of bisphenol A as well as other phenols in the presence of NH4NO3. Mono- and di-nitro bisphenol A have been characterized with IR and 1H NMR techniques.
2011, 22(7): 831-834
doi: 10.1016/j.cclet.2010.12.056
Abstract:
A series of glucose-cholesterol derivatives 8a-8e as ligands for brain targeting liposomes were synthesized. The preparation of compound 6 involved temporary protection of glucose with chlorotrimethylsilicane and hexamethyldisilazane followed by selectively hydrolyzed. The known cholesteryl tosylate 1 were coupled to ethylene glycols to afford alcohol 2a-2e. Substitution and deprotection of alcohol 2a-2e furnished the acids 4a-4e, which was condensed with compound 6 to get compounds 7a-7e, and then was deprotected in tetrahydrofuran with TEA to obtain the title compounds. As a model drug, tegafur was entrapped by liposomes coupled with 8b, and preliminary in vivo evaluation shown 8b could enhance the ability of liposomes delivering tegafur across the blood brain barrier.
A series of glucose-cholesterol derivatives 8a-8e as ligands for brain targeting liposomes were synthesized. The preparation of compound 6 involved temporary protection of glucose with chlorotrimethylsilicane and hexamethyldisilazane followed by selectively hydrolyzed. The known cholesteryl tosylate 1 were coupled to ethylene glycols to afford alcohol 2a-2e. Substitution and deprotection of alcohol 2a-2e furnished the acids 4a-4e, which was condensed with compound 6 to get compounds 7a-7e, and then was deprotected in tetrahydrofuran with TEA to obtain the title compounds. As a model drug, tegafur was entrapped by liposomes coupled with 8b, and preliminary in vivo evaluation shown 8b could enhance the ability of liposomes delivering tegafur across the blood brain barrier.
2011, 22(7): 835-838
doi: 10.1016/j.cclet.2011.01.014
Abstract:
Two new acetylated kaempferol glycosides were isolated from the seeds of Camellia semiserrata Chi, their structures were elucidated as kaempferol-3-O-[(3-0-acetyl)-α-L-rharnnopyranosyl(1→3)(4-O-acetyl)-α-rhamnopyranosyl(l→6)-β-D-gluco-pyranoside] (1) and kaempferol-3-O-[(2-O-acetyl)-α-L-rhamnopyranosyl (1→3)(4-O-acetyl)-α-L-rhamnopyranosyl(l→6)-β-d-gluco-pyranoside] (2) by spectral experiments (including ESI-MS, ID- and 2D-NMR).
Two new acetylated kaempferol glycosides were isolated from the seeds of Camellia semiserrata Chi, their structures were elucidated as kaempferol-3-O-[(3-0-acetyl)-α-L-rharnnopyranosyl(1→3)(4-O-acetyl)-α-rhamnopyranosyl(l→6)-β-D-gluco-pyranoside] (1) and kaempferol-3-O-[(2-O-acetyl)-α-L-rhamnopyranosyl (1→3)(4-O-acetyl)-α-L-rhamnopyranosyl(l→6)-β-d-gluco-pyranoside] (2) by spectral experiments (including ESI-MS, ID- and 2D-NMR).
2011, 22(7): 839-842
doi: 10.1016/j.cclet.2010.12.021
Abstract:
Metabolism study has been carried out on 1-hydroxy-2,3,5-trimethoxyxanthone (HM-1) and 1-hydroxy-2,3,4,7-tetramethoxyxanthone (HM-2), which are two biologically active ingredients isolated from the Tibetan herb, <Halenia elliptica D.Don., in rat liver microsomes in vitro. A method of high performance liquid chromatography coupled to ion trap time-of-flight mass spectrometry (LCMSn-ESI-IT-TOF) was applied to analyze metabolites of HM-1 and HM-2 on line, and five metabolites were identified containing 1,5-dihydroxy-2,3-dimethoxyxanthone (HM-5), 1,7-dihydroxy-2,3,4-trimethoxyxanthone (HM-9), 1,4, 7- trihydroxy-2,3-dimethoxyxanthone (HM-10), 1,4-dihydroxy-2,3,7-trimethoxyxanthone (HM-11) and 1,2-dihydroxy-3,4,7- trimethoxyxanthone (HM-12). Among these metabolites, HM-9, HM-11, and HM-12 were isomers mutually. The results indicated that HM-1 and HM-2 occurred Phase I metabolic reaction of demethylation in rat microsomes in vitro.
Metabolism study has been carried out on 1-hydroxy-2,3,5-trimethoxyxanthone (HM-1) and 1-hydroxy-2,3,4,7-tetramethoxyxanthone (HM-2), which are two biologically active ingredients isolated from the Tibetan herb, <Halenia elliptica D.Don., in rat liver microsomes in vitro. A method of high performance liquid chromatography coupled to ion trap time-of-flight mass spectrometry (LCMSn-ESI-IT-TOF) was applied to analyze metabolites of HM-1 and HM-2 on line, and five metabolites were identified containing 1,5-dihydroxy-2,3-dimethoxyxanthone (HM-5), 1,7-dihydroxy-2,3,4-trimethoxyxanthone (HM-9), 1,4, 7- trihydroxy-2,3-dimethoxyxanthone (HM-10), 1,4-dihydroxy-2,3,7-trimethoxyxanthone (HM-11) and 1,2-dihydroxy-3,4,7- trimethoxyxanthone (HM-12). Among these metabolites, HM-9, HM-11, and HM-12 were isomers mutually. The results indicated that HM-1 and HM-2 occurred Phase I metabolic reaction of demethylation in rat microsomes in vitro.
2011, 22(7): 843-846
doi: 10.1016/j.cclet.2010.12.008
Abstract:
Toxicities of CdSe and CdSe/CdS quantum dots (QDs) synthesized by ultrasound-assisted methods were investigated in vitro and in vivo. Five human cell lines were used to assess the cytotoxicity of as-prepared CdSe and CdSe/CdS by assays of MTT viability, red blood cell hemolysis, flow cytometry, and fluorescence imaging. The results show that these QDs may be cytotoxic by their influence in S and G2 phases in cell cycles. The cytotoxicity of QDs depends on both the physicochemical properties and related to target cells.
Toxicities of CdSe and CdSe/CdS quantum dots (QDs) synthesized by ultrasound-assisted methods were investigated in vitro and in vivo. Five human cell lines were used to assess the cytotoxicity of as-prepared CdSe and CdSe/CdS by assays of MTT viability, red blood cell hemolysis, flow cytometry, and fluorescence imaging. The results show that these QDs may be cytotoxic by their influence in S and G2 phases in cell cycles. The cytotoxicity of QDs depends on both the physicochemical properties and related to target cells.
2011, 22(7): 847-850
doi: 10.1016/j.cclet.2011.01.016
Abstract:
The inclusion complex of β-cyclodextrin (β-CD) with 4-chlorobenzoic acid was synthesized and its crystal structure was determined by single crystal X-ray diffraction under cryogenic condition. The complex contains two β-CDs, two 4-chlorobenzoic acids and twenty-nine water molecules in the asymmetric unit, and can be formulated as 2(C42H70O35) 2(C7H5O2Cl) 29(H2O). In the crystal lattice, two β-CDs form a face-to-face dimer jointed together through hydrogen bonding between the secondary hydroxyl groups of β-CDs. Two 4-chlorobenzoic acid molecules which contact by C-Cl···π interactions are included in the β-CD dimer cavity. The β-CD dimers are arranged in brickwork-like pattern along the crystallographic a-axis. The effect of guest molecule length on the inclusion geometry was discussed by comparative study of some β-CD complexes containing similar guests. # 2011 En Ju Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
The inclusion complex of β-cyclodextrin (β-CD) with 4-chlorobenzoic acid was synthesized and its crystal structure was determined by single crystal X-ray diffraction under cryogenic condition. The complex contains two β-CDs, two 4-chlorobenzoic acids and twenty-nine water molecules in the asymmetric unit, and can be formulated as 2(C42H70O35) 2(C7H5O2Cl) 29(H2O). In the crystal lattice, two β-CDs form a face-to-face dimer jointed together through hydrogen bonding between the secondary hydroxyl groups of β-CDs. Two 4-chlorobenzoic acid molecules which contact by C-Cl···π interactions are included in the β-CD dimer cavity. The β-CD dimers are arranged in brickwork-like pattern along the crystallographic a-axis. The effect of guest molecule length on the inclusion geometry was discussed by comparative study of some β-CD complexes containing similar guests. # 2011 En Ju Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
2011, 22(7): 851-854
doi: 10.1016/j.cclet.2010.12.029
Abstract:
The determination method of L-phenylalanine (LPA) by fluorescence quenching was developed. The assay was based on the combination of the cucurbit[7]uril (CB[7]) with palmatine hydrochloride (PAL) reaction. In the presence of CB[7], the fluorescence of PAL was quenched by LPA which can be employed to detect LPA. Under the optimal conditions, a linear range 3.63×10-8-9.68×10-6 mol/L and a detection limit 1.27×10-8 mol/L of LPA were obtained. The relative standard deviation (R.S.D) was 1.8% obtained from a series of11 standards each containing 6.05×10-6 mol/L oLPA. This paper also discusses the mechanism of fluorescence indicator probe.
The determination method of L-phenylalanine (LPA) by fluorescence quenching was developed. The assay was based on the combination of the cucurbit[7]uril (CB[7]) with palmatine hydrochloride (PAL) reaction. In the presence of CB[7], the fluorescence of PAL was quenched by LPA which can be employed to detect LPA. Under the optimal conditions, a linear range 3.63×10-8-9.68×10-6 mol/L and a detection limit 1.27×10-8 mol/L of LPA were obtained. The relative standard deviation (R.S.D) was 1.8% obtained from a series of11 standards each containing 6.05×10-6 mol/L oLPA. This paper also discusses the mechanism of fluorescence indicator probe.
2011, 22(7): 855-858
doi: 10.1016/j.cclet.2010.12.022
Abstract:
The conformational behaviors of monosodium glutamate (MSG) in a dehydration process were studied by Micro-Raman spectroscopy in combination with Hartree-Fock calculations using 6-31+G* method. The dehydration process of the MSG droplet was performed by decreasing the ambient relative humidity (RH). The intensity ratio of the 935 cm-1 band to 884 cm-1 band (I935/ I884) kept decreasing when RH decreased. By optimizing the geometries with different fixed dihedral angles, the downtrend of (I935/ I884) is found to be due to the reduction of MSG molecular volume.
The conformational behaviors of monosodium glutamate (MSG) in a dehydration process were studied by Micro-Raman spectroscopy in combination with Hartree-Fock calculations using 6-31+G* method. The dehydration process of the MSG droplet was performed by decreasing the ambient relative humidity (RH). The intensity ratio of the 935 cm-1 band to 884 cm-1 band (I935/ I884) kept decreasing when RH decreased. By optimizing the geometries with different fixed dihedral angles, the downtrend of (I935/ I884) is found to be due to the reduction of MSG molecular volume.
2011, 22(7): 859-862
doi: 10.1016/j.cclet.2010.12.049
Abstract:
Porous graphene oxide/chitosan (PGOC) materials were prepared by a unidirectional freeze-drying method. Their porous structure, mechanical property and adsorption for metal ions were investigated. The results show that the incorporation of graphene oxide (GO) significantly increased the compressive strength of the PGOC materials. The saturated adsorption capacity of Pb2+ increased about 31%, up to 99 mg/g when 5 wt% GO was incorporated These biodegradable, nontoxic, efficient PGOC materials will be a potential adsorbent for metal ions in aqueous solution.
Porous graphene oxide/chitosan (PGOC) materials were prepared by a unidirectional freeze-drying method. Their porous structure, mechanical property and adsorption for metal ions were investigated. The results show that the incorporation of graphene oxide (GO) significantly increased the compressive strength of the PGOC materials. The saturated adsorption capacity of Pb2+ increased about 31%, up to 99 mg/g when 5 wt% GO was incorporated These biodegradable, nontoxic, efficient PGOC materials will be a potential adsorbent for metal ions in aqueous solution.
2011, 22(7): 863-866
doi: 10.1016/j.cclet.2011.01.006
Abstract:
A novel cell-impermeable zinc sensor was synthesized by incorporating poly(ethylene glycol) (PEG) to N-(8-quinolyl)-p-aminobenzenesulfonamide (HQAS) group. The polymeric zinc sensor combines both valuable features of HQAS and PEG. The HQAS of the sensor has the similar functions to TSQ, and exhibits a good fluorescence response to Zn2+ but poor fluorescence responses to other metal ions. The PEG chain can prevent the sensor to permeate healthy cell membrane. The stained experiments with the yeast cells as model showed that the sensor cannot stain the healthy yeast cells, but only the damaged or died yeast cells. These results indicated the novel zinc probe was a typical cell-impermeable zinc sensor.
A novel cell-impermeable zinc sensor was synthesized by incorporating poly(ethylene glycol) (PEG) to N-(8-quinolyl)-p-aminobenzenesulfonamide (HQAS) group. The polymeric zinc sensor combines both valuable features of HQAS and PEG. The HQAS of the sensor has the similar functions to TSQ, and exhibits a good fluorescence response to Zn2+ but poor fluorescence responses to other metal ions. The PEG chain can prevent the sensor to permeate healthy cell membrane. The stained experiments with the yeast cells as model showed that the sensor cannot stain the healthy yeast cells, but only the damaged or died yeast cells. These results indicated the novel zinc probe was a typical cell-impermeable zinc sensor.
2011, 22(7): 867-870
doi: 10.1016/j.cclet.2010.12.042
Abstract:
We reported an interfacial self-assembly of regularly layered porous poly(4-vinylpyridine) (P4VP) films at the interfaces of water-chloroform or-dichloroethane. The porous diameters were in the range from hundred nanometers to several micrometers. It was revealed that formation of such kind of porous materials was solvent dependent. Moreover, cyclic Ag nanoparticles could be grown in the porous P4VP films to form Ag–P4VP nanohybrids under radiation.
We reported an interfacial self-assembly of regularly layered porous poly(4-vinylpyridine) (P4VP) films at the interfaces of water-chloroform or-dichloroethane. The porous diameters were in the range from hundred nanometers to several micrometers. It was revealed that formation of such kind of porous materials was solvent dependent. Moreover, cyclic Ag nanoparticles could be grown in the porous P4VP films to form Ag–P4VP nanohybrids under radiation.
2011, 22(7): 871-874
doi: 10.1016/j.cclet.2011.01.004
Abstract:
The green synthesis of chloropropylene carbonate via the coupling reaction of carbon dioxide and epichlorohydrin had been achieved using halogen-free and single-component catalysts tetrabutylammonium salts of tritransition-metal-substituted A-α-tungstogermanate [(n-C4H9)4N]3H7GeW9M3(H2O)3O37 (M = CuⅡ, NiⅡ, CoⅡ and MnⅡ) without any solvent. The catalytic activity was significantly depended on the transition metal introduced in polyoxometalates. [(n-C4H9)4N]3H7GeW9Mn3(H2O)3O37 exhibited the highest catalytic activity with 94.9% conversion for epichlorohydrin and 98% selectivity for chloropropylene carbonate in 3 h. Plausible mechanism was proposed based on the results.
The green synthesis of chloropropylene carbonate via the coupling reaction of carbon dioxide and epichlorohydrin had been achieved using halogen-free and single-component catalysts tetrabutylammonium salts of tritransition-metal-substituted A-α-tungstogermanate [(n-C4H9)4N]3H7GeW9M3(H2O)3O37 (M = CuⅡ, NiⅡ, CoⅡ and MnⅡ) without any solvent. The catalytic activity was significantly depended on the transition metal introduced in polyoxometalates. [(n-C4H9)4N]3H7GeW9Mn3(H2O)3O37 exhibited the highest catalytic activity with 94.9% conversion for epichlorohydrin and 98% selectivity for chloropropylene carbonate in 3 h. Plausible mechanism was proposed based on the results.
2011, 22(7): 875-878
doi: 10.1016/j.cclet.2011.01.001
Abstract:
The nanoreactors were fabricated by reacting amphiphilic quaternary ammoniums and polyoxoperoxometalates Kn[PW12-xTix-O40-x(02)x] (x=1, 2 and 3; n = 5, 7 and 9) (K5[PW11TiO39(O2)], K7[PW10Ti2O38(O2)2] and K9[PW9Ti3O37(O2)3]). Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) were used to characterize the resulting samples. This kind of nanocatalysts could promote NH4SCN' degradation into simple inorganic compounds such as SO42-, HCO3- and NO3- only using oxygen as an oxidant under room conditions.
The nanoreactors were fabricated by reacting amphiphilic quaternary ammoniums and polyoxoperoxometalates Kn[PW12-xTix-O40-x(02)x] (x=1, 2 and 3; n = 5, 7 and 9) (K5[PW11TiO39(O2)], K7[PW10Ti2O38(O2)2] and K9[PW9Ti3O37(O2)3]). Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) were used to characterize the resulting samples. This kind of nanocatalysts could promote NH4SCN' degradation into simple inorganic compounds such as SO42-, HCO3- and NO3- only using oxygen as an oxidant under room conditions.
2011, 22(7): 879-882
doi: 10.1016/j.cclet.2010.12.032
Abstract:
The synthesis of nanostructured Cu2O was conducted in a non-aqueous solution via polyol method at a temperature of 130 ℃. It was found that the formation of Cu2O nanobelts was heavily dependent on the presence of surfactant cetyltrimethylammonium bromide (CTAB). Cu2O nanobelts with 100-400 nm in width and several micrometers in length were only observed when CTAB was used, whereas in other cases where CTAB was absent or CTAB was replaced with polyvinylpyrrolidone (PVP K-30), only spherical or cube-like particles were formed. The formation mechanism of Cu2O nanobelts was discussed.
The synthesis of nanostructured Cu2O was conducted in a non-aqueous solution via polyol method at a temperature of 130 ℃. It was found that the formation of Cu2O nanobelts was heavily dependent on the presence of surfactant cetyltrimethylammonium bromide (CTAB). Cu2O nanobelts with 100-400 nm in width and several micrometers in length were only observed when CTAB was used, whereas in other cases where CTAB was absent or CTAB was replaced with polyvinylpyrrolidone (PVP K-30), only spherical or cube-like particles were formed. The formation mechanism of Cu2O nanobelts was discussed.
