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2008 Volume 19 Issue 7
2008, 19(7): 759-761
doi: 10.1016/j.cclet.2008.04.032
Abstract:
Valsartan 1,one of the most important agents used in antihypertensive therapy today,was synthesized starting from L-valin methyl ester hydrochloride 2 through four steps in an overall yield of 60%.The key step involves the palladium-catalyzed SuzuKi coupling.This method overcomes many of the drawbacks associated with the previously reported syntheses and is more suitable for industrial production.
Valsartan 1,one of the most important agents used in antihypertensive therapy today,was synthesized starting from L-valin methyl ester hydrochloride 2 through four steps in an overall yield of 60%.The key step involves the palladium-catalyzed SuzuKi coupling.This method overcomes many of the drawbacks associated with the previously reported syntheses and is more suitable for industrial production.
2008, 19(7): 762-766
doi: 10.1016/j.cclet.2008.05.007
Abstract:
A simple one-pot synthetic method for the preparation of 2,4,5-triaryl-lH-imidazoles from benzoin or benzil,ammonium acetate,aromatic aldehydes,and ZrOCl2·8H 2O catalyst is described.The ZrOCl2-8H2O catalyst was found to be equally effective for aromatic and heteroaromatic aldehydes and also for the preparation of substituted 1,4-di(4,5-diphenylimidazol-yl) benzene.
A simple one-pot synthetic method for the preparation of 2,4,5-triaryl-lH-imidazoles from benzoin or benzil,ammonium acetate,aromatic aldehydes,and ZrOCl2·8H 2O catalyst is described.The ZrOCl2-8H2O catalyst was found to be equally effective for aromatic and heteroaromatic aldehydes and also for the preparation of substituted 1,4-di(4,5-diphenylimidazol-yl) benzene.
2008, 19(7): 767-770
doi: 10.1016/j.cclet.2008.05.006
Abstract:
An efficient conversion of β-diketones into corresponding β-keto enol ethers with catalytic amount of PMA-SiO2 has been achieve
An efficient conversion of β-diketones into corresponding β-keto enol ethers with catalytic amount of PMA-SiO2 has been achieve
2008, 19(7): 771-774
doi: 10.1016/j.cclet.2008.05.005
Abstract:
PMA-SiO2 has been utilized as an efficient catalyst system in preparation of 1,8-dioxooctabydroxanthenes.
PMA-SiO2 has been utilized as an efficient catalyst system in preparation of 1,8-dioxooctabydroxanthenes.
2008, 19(7): 775-779
doi: 10.1016/j.cclet.2008.04.040
Abstract:
A general and convenient practical approach for the synthesis of polyhydroquinoline derivatives has been achieved via one-pot four-component Hantzsch condensation of aromatic aldehydes,dimedone,ethyl acetoacetate and ammonium acetate in the presence of a catalytic amount of cerium(Ⅳ) ammonium nitrate (CAN),in ethanol solvent at ambient temperature.Simple work-up,mild reaction conditions,inexpensive and non-toxic catalyst,and excellent product yields are the advantageous features of this method.
A general and convenient practical approach for the synthesis of polyhydroquinoline derivatives has been achieved via one-pot four-component Hantzsch condensation of aromatic aldehydes,dimedone,ethyl acetoacetate and ammonium acetate in the presence of a catalytic amount of cerium(Ⅳ) ammonium nitrate (CAN),in ethanol solvent at ambient temperature.Simple work-up,mild reaction conditions,inexpensive and non-toxic catalyst,and excellent product yields are the advantageous features of this method.
2008, 19(7): 780-782
doi: 10.1016/j.cclet.2008.04.011
Abstract:
Photocyclisation of substituted (E)-3-hydroxy-2-(1´-methyl-2´-phenylvinyl)-4-oxo-4H-1-benzopyrans to yield linear novel tricyclic 9H-furo[3,2-b]chromen-9-ones and angular fused tetracyclic xanthenones is described.
Photocyclisation of substituted (E)-3-hydroxy-2-(1´-methyl-2´-phenylvinyl)-4-oxo-4H-1-benzopyrans to yield linear novel tricyclic 9H-furo[3,2-b]chromen-9-ones and angular fused tetracyclic xanthenones is described.
2008, 19(7): 783-787
doi: 10.1016/j.cclet.2008.05.016
Abstract:
A variety of terminal arylacetylenes have been conveniently synthesized in good to high yields via Sonogashira coupling of aryl iodides with (trimethylsilyl)acetylene catalyzed by MCM-41-supported mercapto palladium(0) complex,followed by desilylation under mild conditions.This polymeric palladium catalyst can be reused many times without any decrease in activity.
A variety of terminal arylacetylenes have been conveniently synthesized in good to high yields via Sonogashira coupling of aryl iodides with (trimethylsilyl)acetylene catalyzed by MCM-41-supported mercapto palladium(0) complex,followed by desilylation under mild conditions.This polymeric palladium catalyst can be reused many times without any decrease in activity.
2008, 19(7): 788-790
doi: 10.1016/j.cclet.2008.04.041
Abstract:
Green conditions have been developed for the synthesis of substituted 2-aminothiopbenes employing multicomponent reactions of a ketone with active methylene nitrile and elemental sulphur induced by free solar thermal energy.
Green conditions have been developed for the synthesis of substituted 2-aminothiopbenes employing multicomponent reactions of a ketone with active methylene nitrile and elemental sulphur induced by free solar thermal energy.
2008, 19(7): 791-794
doi: 10.1016/j.cclet.2008.04.038
Abstract:
The esterifications of 9-(hydroxyimino)-4-methyl-8,9-dihydrofuro[2,3-h]chromen-2-one (4) with acid chlorides afforded normal oxime-esters 3a-e in 35-78% yields in presence of excessive 4-dimethylaminopyridine as the acid scavenger,whereas the reactions gave unexpected 8-substituted products N-(8-chloro-4-methyl-2-oxo-2H-furo-[2,3-h]chromen-9-y1)amides (5a-c)and 4-methyl-2,9-dioxo-8,9-dihydro-2H-furo[2,3-h]chromen-8-ylcarboxyloates (6d-e) by using excessive acid chlorides.The structures of 10 new compounds were determined by 1H NMR,13C NMR,MS and HRMS,and the possible mechanism for the formation of unexpected products 5a-e and 6d-e was also proposed.
The esterifications of 9-(hydroxyimino)-4-methyl-8,9-dihydrofuro[2,3-h]chromen-2-one (4) with acid chlorides afforded normal oxime-esters 3a-e in 35-78% yields in presence of excessive 4-dimethylaminopyridine as the acid scavenger,whereas the reactions gave unexpected 8-substituted products N-(8-chloro-4-methyl-2-oxo-2H-furo-[2,3-h]chromen-9-y1)amides (5a-c)and 4-methyl-2,9-dioxo-8,9-dihydro-2H-furo[2,3-h]chromen-8-ylcarboxyloates (6d-e) by using excessive acid chlorides.The structures of 10 new compounds were determined by 1H NMR,13C NMR,MS and HRMS,and the possible mechanism for the formation of unexpected products 5a-e and 6d-e was also proposed.
2008, 19(7): 795-796
doi: 10.1016/j.cclet.2008.04.044
Abstract:
2-Oxo-3R,4S,5S,6S-tetraethoxyazepane was conveniently synthesized from D-glucono-1,5-lactone with a yield of 10% overall.The key step of synthetic route-reductive 1,6-cyclization was completed efficiently by using Ph3P to give the expected lactam.
2-Oxo-3R,4S,5S,6S-tetraethoxyazepane was conveniently synthesized from D-glucono-1,5-lactone with a yield of 10% overall.The key step of synthetic route-reductive 1,6-cyclization was completed efficiently by using Ph3P to give the expected lactam.
2008, 19(7): 797-800
doi: 10.1016/j.cclet.2008.04.045
Abstract:
A novel chiral stationary phase (CSP) was prepared by immobilizing mono(6A-N-1-(2-hydroxyl)-phenylethylimino-6A-deoxy)-β-cyclodextrin onto the surface of silica gel via a longer spacer.This chiral stationary phase exhibited good enantios electivity for a variety of chiral compounds under reversed-phase conditions.
A novel chiral stationary phase (CSP) was prepared by immobilizing mono(6A-N-1-(2-hydroxyl)-phenylethylimino-6A-deoxy)-β-cyclodextrin onto the surface of silica gel via a longer spacer.This chiral stationary phase exhibited good enantios electivity for a variety of chiral compounds under reversed-phase conditions.
2008, 19(7): 801-804
doi: 10.1016/j.cclet.2008.04.046
Abstract:
A series of new O6-BG derivatives (14-21,23-30) were synthesized as inactivators of O6-Alkylguanine-DNA alkyltransferase (AGT), and their ability to inhibit AGT was preliminary evaluated by MTT with O6-BG as the control. The result suggested compound 30 displayed a higher activity than O6-BG.
A series of new O6-BG derivatives (14-21,23-30) were synthesized as inactivators of O6-Alkylguanine-DNA alkyltransferase (AGT), and their ability to inhibit AGT was preliminary evaluated by MTT with O6-BG as the control. The result suggested compound 30 displayed a higher activity than O6-BG.
2008, 19(7): 805-806
doi: 10.1016/j.cclet.2008.04.037
Abstract:
Ligudentatin A 1,a new phenolic norsesquiterpenes,was first synthesized starting from (+)-periUaldehyde 3 through five steps,successively,in an overall yield of 20.8%.The key steps were the Diels-Alder reaction and aromatization of enone to phenol.
Ligudentatin A 1,a new phenolic norsesquiterpenes,was first synthesized starting from (+)-periUaldehyde 3 through five steps,successively,in an overall yield of 20.8%.The key steps were the Diels-Alder reaction and aromatization of enone to phenol.
2008, 19(7): 807-810
doi: 10.1016/j.cclet.2008.05.023
Abstract:
Phenylazonaphthalene peptide nucleic acid (PNA) monomers were successfully synthesized,and their photoisomerization was examined.The new PNA monomers showed reversible trans-cis isomerization with UV and visible light irradiation,which might be the foundation of photo-regulating the hybridization between PNA containing phenylazonaphthalene unit and DNA.Simultaneously,the fluorescence of the new PNA monomers might make them especially useful as structural probes.
Phenylazonaphthalene peptide nucleic acid (PNA) monomers were successfully synthesized,and their photoisomerization was examined.The new PNA monomers showed reversible trans-cis isomerization with UV and visible light irradiation,which might be the foundation of photo-regulating the hybridization between PNA containing phenylazonaphthalene unit and DNA.Simultaneously,the fluorescence of the new PNA monomers might make them especially useful as structural probes.
2008, 19(7): 811-813
doi: 10.1016/j.cclet.2008.05.011
Abstract:
Nine racemic homocamptothecin derivatives were synthesized and in vitro antitumor activities were evaluated by standard MTT method.The results showed that some of the compound had higher antitumor activity than iritecan.
Nine racemic homocamptothecin derivatives were synthesized and in vitro antitumor activities were evaluated by standard MTT method.The results showed that some of the compound had higher antitumor activity than iritecan.
2008, 19(7): 814-816
doi: 10.1016/j.cclet.2008.05.009
Abstract:
A convenient approach for the preparation of (2S,3R,4R,5S,6R)-2-(3-(4-ethylbenzyl)-4-chlorophenyl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol 1 is developed.The target compound via four steps is synthesized from 4-bromo-2-(bromomethyl)-1-chlorobenzene and the isomers of undesired ortho-products were avoided during the preparation.
A convenient approach for the preparation of (2S,3R,4R,5S,6R)-2-(3-(4-ethylbenzyl)-4-chlorophenyl)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol 1 is developed.The target compound via four steps is synthesized from 4-bromo-2-(bromomethyl)-1-chlorobenzene and the isomers of undesired ortho-products were avoided during the preparation.
2008, 19(7): 817-820
doi: 10.1016/j.cclet.2008.04.030
Abstract:
A new triterpenoid glycoside,3-β-O-β-D-glucopyranosyl presenegenin 28-O-α-L-arabipyranosyl(1→3)-β-D-xylopyranosyl(1→4)-[β-D-apiofuranosyl(1→3)]-α-L-rhanmopyranosyl(1→2)-[α-L-rhamnopyranosyl(1→3)]-β-D-fucopyranosyl ester (1) was isolated from the Polygala tenuifolia Willd.,together with two known saponins,including polygalasaponinⅩⅩⅣ (2) and polygalasaponinⅩⅩⅧ(3).The structure of new compound was elucidated by spectroscopic methods.
A new triterpenoid glycoside,3-β-O-β-D-glucopyranosyl presenegenin 28-O-α-L-arabipyranosyl(1→3)-β-D-xylopyranosyl(1→4)-[β-D-apiofuranosyl(1→3)]-α-L-rhanmopyranosyl(1→2)-[α-L-rhamnopyranosyl(1→3)]-β-D-fucopyranosyl ester (1) was isolated from the Polygala tenuifolia Willd.,together with two known saponins,including polygalasaponinⅩⅩⅣ (2) and polygalasaponinⅩⅩⅧ(3).The structure of new compound was elucidated by spectroscopic methods.
2008, 19(7): 821-824
doi: 10.1016/j.cclet.2008.04.031
Abstract:
Two new acylated C-glycosylflavones were isolated from the leaves of Iris lactea vat.chinensis,and their structures were elucidated on the basis of extensive NMR experiments and mass spectrometry methods and were assigned as 5-hydroxy-4´-methoxyflavone-7-O-(β-D-2""4""-diacetylrhamnopyranosyl)-6-C-[O-(α-L-6´´´-acetyl-glucopyranosyl)-1→2-β-D-glucopyranoside] (irislactin A) and 5-hydroxy-4´,7-dimethoxyflavone-6-C-[O-(α-L-2´´´,3´´´-diacetylrhamno-pyranosyl)-1→2-β-D-glucopyranoside] (irislactin B).
Two new acylated C-glycosylflavones were isolated from the leaves of Iris lactea vat.chinensis,and their structures were elucidated on the basis of extensive NMR experiments and mass spectrometry methods and were assigned as 5-hydroxy-4´-methoxyflavone-7-O-(β-D-2""4""-diacetylrhamnopyranosyl)-6-C-[O-(α-L-6´´´-acetyl-glucopyranosyl)-1→2-β-D-glucopyranoside] (irislactin A) and 5-hydroxy-4´,7-dimethoxyflavone-6-C-[O-(α-L-2´´´,3´´´-diacetylrhamno-pyranosyl)-1→2-β-D-glucopyranoside] (irislactin B).
2008, 19(7): 825-828
doi: 10.1016/j.cclet.2008.04.033
Abstract:
Two new steroidal glucosides,26-O-β-D-glucopyranosyl (25S)-furost-5-ene-1β,3β,22α,26-tetraol 1-O-β-D-xylopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-β-D-fucopyranoside and (25R) spirost-5-ene-3β,14α-diol-3-β-O-β-L-rhamnopyranosyl-(1→2)-[β-D-xylopyranosyl(1→4)]-β-D-glucopyranoside,were isolated from the Ophiopogon japonicus (L.f.) Ker-Gaw.Their structures were elucidated by spectroscopic methods.
Two new steroidal glucosides,26-O-β-D-glucopyranosyl (25S)-furost-5-ene-1β,3β,22α,26-tetraol 1-O-β-D-xylopyranosyl-(1→3)-[α-L-rhamnopyranosyl-(1→2)]-β-D-fucopyranoside and (25R) spirost-5-ene-3β,14α-diol-3-β-O-β-L-rhamnopyranosyl-(1→2)-[β-D-xylopyranosyl(1→4)]-β-D-glucopyranoside,were isolated from the Ophiopogon japonicus (L.f.) Ker-Gaw.Their structures were elucidated by spectroscopic methods.
2008, 19(7): 829-831
doi: 10.1016/j.cclet.2008.05.003
Abstract:
A new cafferic ester,(+)-2-(1-hydroxyl-4-oxocyclobexyl) ethyl caffeate,was isolated from the 80% ethanol extract of the whole plants of Incarvillea mairei var.granditlora (Wehrhahn) Grierson.The structure of the compound was established by spectroscopic methods.
A new cafferic ester,(+)-2-(1-hydroxyl-4-oxocyclobexyl) ethyl caffeate,was isolated from the 80% ethanol extract of the whole plants of Incarvillea mairei var.granditlora (Wehrhahn) Grierson.The structure of the compound was established by spectroscopic methods.
2008, 19(7): 832-834
doi: 10.1016/j.cclet.2008.05.019
Abstract:
A new alkaloid,named 6-(2´, 3´-dihydroxy-4´hydroxymethyl-tetrahydro-furan-1´-y1)cyclopentadiene[c]pyrrole-1,3-diol,was isolated from the seeds of Castanea mollissima Blume.The structure was elucidated based on spectroscopic evidence including 2D NMR techniques.
A new alkaloid,named 6-(2´, 3´-dihydroxy-4´hydroxymethyl-tetrahydro-furan-1´-y1)cyclopentadiene[c]pyrrole-1,3-diol,was isolated from the seeds of Castanea mollissima Blume.The structure was elucidated based on spectroscopic evidence including 2D NMR techniques.
2008, 19(7): 835-836
doi: 10.1016/j.cclet.2008.04.034
Abstract:
A new hopane triterpenoid,hopane 22,29-diol-29-formate(1),has been isolated from the whole herbs of Saxiglossum angustissimum (Gies.) Ching and its structure has been successfully determined on the basis of spectroscopic evidences.
A new hopane triterpenoid,hopane 22,29-diol-29-formate(1),has been isolated from the whole herbs of Saxiglossum angustissimum (Gies.) Ching and its structure has been successfully determined on the basis of spectroscopic evidences.
2008, 19(7): 837-840
doi: 10.1016/j.cclet.2008.05.017
Abstract:
A new compound,3,6,20(S)-trihydroxy-12,23-epoxydammar-24-ene,6,20-di-O-β-D-glucopyranoside (1),was isolated from the leaves of Panax ginseng C.A.Meyer,whose structural elucidation was carried out by means of spectral analysis (including IR,HRFAB-MS and NMR).This compound showed the moderate eytotoxie activities against U937 and HeLa ceils by using the MTT method.
A new compound,3,6,20(S)-trihydroxy-12,23-epoxydammar-24-ene,6,20-di-O-β-D-glucopyranoside (1),was isolated from the leaves of Panax ginseng C.A.Meyer,whose structural elucidation was carried out by means of spectral analysis (including IR,HRFAB-MS and NMR).This compound showed the moderate eytotoxie activities against U937 and HeLa ceils by using the MTT method.
2008, 19(7): 841-844
doi: 10.1016/j.cclet.2008.04.036
Abstract:
A new bakkenolide-type compound, bakkenolide-Va(1), was isolated from the rhizome of Petasites tricholobus. The structure was characterized on the basis of various NMR (1H, 13C, 1H-1H COSY, HMQC, HMBC and NOESY) and mass spectrometry data. The neuroprotective activity of bakkenolide-Va was investigated in primarily cultured neurons treated by hypoxia-glucose deprivation and various types of oxidative insults.
A new bakkenolide-type compound, bakkenolide-Va(1), was isolated from the rhizome of Petasites tricholobus. The structure was characterized on the basis of various NMR (1H, 13C, 1H-1H COSY, HMQC, HMBC and NOESY) and mass spectrometry data. The neuroprotective activity of bakkenolide-Va was investigated in primarily cultured neurons treated by hypoxia-glucose deprivation and various types of oxidative insults.
2008, 19(7): 845-848
doi: 10.1016/j.cclet.2008.04.043
Abstract:
A new ionone glycoside (6R,9R)-blumenyl α-L-rhanmopyranosyl-(1→6)-β-D-gluco-pyranoside (1),together with a new natural product 2-methoxyl-4-trans-propenyl-phenol α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (2),was isolated from the leaves of Neoalsomitra integrifoliola.Their structures were elucidated by chemical and spectral analysis.Compound 1 showed weak anti-inflammatory and low-level antioxidant activities.
A new ionone glycoside (6R,9R)-blumenyl α-L-rhanmopyranosyl-(1→6)-β-D-gluco-pyranoside (1),together with a new natural product 2-methoxyl-4-trans-propenyl-phenol α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (2),was isolated from the leaves of Neoalsomitra integrifoliola.Their structures were elucidated by chemical and spectral analysis.Compound 1 showed weak anti-inflammatory and low-level antioxidant activities.
2008, 19(7): 849-851
doi: 10.1016/j.cclet.2008.05.018
Abstract:
A new ent-abietane diterpenoid,named dayecrystal C,was isolated from the EtOAc extract of the dried leaves of Isodon macrophyllus.Its structure was determined on the basis of spectroscopic methods.
A new ent-abietane diterpenoid,named dayecrystal C,was isolated from the EtOAc extract of the dried leaves of Isodon macrophyllus.Its structure was determined on the basis of spectroscopic methods.
2008, 19(7): 852-854
doi: 10.1016/j.cclet.2008.05.012
Abstract:
Two new diterpenoids,named glaucocalyxin F and glaucocalyxin X,respectively,were isolated from the whole plant of Rabdosia japonica (Burro.f.) Hara vat.glaucocalyx (Maxim.) Hara.Their structures was established on the basis of spectral analysis.
Two new diterpenoids,named glaucocalyxin F and glaucocalyxin X,respectively,were isolated from the whole plant of Rabdosia japonica (Burro.f.) Hara vat.glaucocalyx (Maxim.) Hara.Their structures was established on the basis of spectral analysis.
2008, 19(7): 855-859
doi: 10.1016/j.cclet.2008.04.029
Abstract:
A novel,rapid and simple CdTe quantum dots (QDs) based technology platform was established for selective and sensitive determination of vitamin B6 in aqueous solution.It can perform accurate and reproducible quantification of vitamin B6 in pharmaceutical with satisfactory results.
A novel,rapid and simple CdTe quantum dots (QDs) based technology platform was established for selective and sensitive determination of vitamin B6 in aqueous solution.It can perform accurate and reproducible quantification of vitamin B6 in pharmaceutical with satisfactory results.
2008, 19(7): 860-864
doi: 10.1016/j.cclet.2008.04.047
Abstract:
The simultaneous determination of cobalt,copper and nickel using 1-(2-thiazolylazo)-2-naphthol (first figure of this article) by spectrophotometric method is a difficult problem in analytical chemistry,due to spectral interferences.By multivariate calibration methods,such as partial least squares (PLS) regression,it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range.Orthogonal signal correction (OSC) is a preprocessing technique used for removing the information unrelated to the target variables based on constrained principal component analysis.OSC is a suitable preprocessing method for PLS calibration of mixtures without loss of prediction capacity using spectrophotometric method.In this study,the calibration model is based on absorption spectra in the 550-750-nm range for 21 different mixtures of cobalt,copper and nickel.Calibration matrices were formed from samples containing 0.05-1.05,0.05-1.30 and 0.05-0.80 μg mL-1 for cobalt,copper and nickel,respectively.The root mean square error of prediction (RMSEP) for cobalt,copper and nickel with OSC and without OSC were 0.007,0.008,0.011 and 0.031,0.037,0.032 μg mL-1,respectively.This procedure allows the simultaneous determination of cobalt,copper and nickel in synthetic and real samples and good reliability of the determination was proved.
The simultaneous determination of cobalt,copper and nickel using 1-(2-thiazolylazo)-2-naphthol (first figure of this article) by spectrophotometric method is a difficult problem in analytical chemistry,due to spectral interferences.By multivariate calibration methods,such as partial least squares (PLS) regression,it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range.Orthogonal signal correction (OSC) is a preprocessing technique used for removing the information unrelated to the target variables based on constrained principal component analysis.OSC is a suitable preprocessing method for PLS calibration of mixtures without loss of prediction capacity using spectrophotometric method.In this study,the calibration model is based on absorption spectra in the 550-750-nm range for 21 different mixtures of cobalt,copper and nickel.Calibration matrices were formed from samples containing 0.05-1.05,0.05-1.30 and 0.05-0.80 μg mL-1 for cobalt,copper and nickel,respectively.The root mean square error of prediction (RMSEP) for cobalt,copper and nickel with OSC and without OSC were 0.007,0.008,0.011 and 0.031,0.037,0.032 μg mL-1,respectively.This procedure allows the simultaneous determination of cobalt,copper and nickel in synthetic and real samples and good reliability of the determination was proved.
2008, 19(7): 865-867
doi: 10.1016/j.cclet.2008.05.004
Abstract:
A novel method was developed for the sensitive determination of nickel in environmental water samples by using TiO2 nanotubes,a new nanomaterial,as solid phase extraction absorbent.In general,TiO2 nanomaterials were often used for catalytic degradation of pollutants in environmental field,and only a very few application in environmental analytic chemistry.In present work,TiO2 nanotubes was firstly used for the enrichment of nickel and the factors would influence the preconcentration performance were optimized.Under the optimal conditions,TiO2 nanotubes exhibited its good enrichment capacity for nickel and the detection limit of the proposed method was 1 ng mL-1.The proposed method was validated with real water samples,and excellent results were obtained with the spiked recoveries in the range of 94.4-99.2%,respectively.
A novel method was developed for the sensitive determination of nickel in environmental water samples by using TiO2 nanotubes,a new nanomaterial,as solid phase extraction absorbent.In general,TiO2 nanomaterials were often used for catalytic degradation of pollutants in environmental field,and only a very few application in environmental analytic chemistry.In present work,TiO2 nanotubes was firstly used for the enrichment of nickel and the factors would influence the preconcentration performance were optimized.Under the optimal conditions,TiO2 nanotubes exhibited its good enrichment capacity for nickel and the detection limit of the proposed method was 1 ng mL-1.The proposed method was validated with real water samples,and excellent results were obtained with the spiked recoveries in the range of 94.4-99.2%,respectively.
2008, 19(7): 868-870
doi: 10.1016/j.cclet.2008.05.001
Abstract:
Hyperbranched poly(amine-ester)s bearing serf-complementary quadruple hydrogen bonding units display excellent mechanical and temperature-dependent melt rheological properties,which make them suitable as novel hot-melting materials.
Hyperbranched poly(amine-ester)s bearing serf-complementary quadruple hydrogen bonding units display excellent mechanical and temperature-dependent melt rheological properties,which make them suitable as novel hot-melting materials.
2008, 19(7): 871-876
doi: 10.1016/j.cclet.2008.05.015
Abstract:
The liquid membrane oscillation of a novel water (aqueous tetradecyl trimethyl ammoniumbromide,TTAB and alcohol sohition)/oil (picdcacid in chloroform sohition)/water (aqueous glucose solution) system was investigated.By using homemade device,the curves of various liquid membranes oscillation with different concentration of TTAB and picric acid,types of alcohol and other organic solvents at different temperature were measured.The results show that the water (aqueous 7 mmol/L of TTAB and 0.5 mol/L of n-propanol solution)/oil (0.5 mmol/L of picric acid in chloroform solution)/water (aqueous glucose solution) system performed sustained and stable oscillation at 30℃.And the novel system can recognise added amino acid.
The liquid membrane oscillation of a novel water (aqueous tetradecyl trimethyl ammoniumbromide,TTAB and alcohol sohition)/oil (picdcacid in chloroform sohition)/water (aqueous glucose solution) system was investigated.By using homemade device,the curves of various liquid membranes oscillation with different concentration of TTAB and picric acid,types of alcohol and other organic solvents at different temperature were measured.The results show that the water (aqueous 7 mmol/L of TTAB and 0.5 mol/L of n-propanol solution)/oil (0.5 mmol/L of picric acid in chloroform solution)/water (aqueous glucose solution) system performed sustained and stable oscillation at 30℃.And the novel system can recognise added amino acid.
2008, 19(7): 877-880
doi: 10.1016/j.cclet.2008.05.002
Abstract:
Monodispersed Fe3O4/polypyrrole (PPy) hollow particles were synthesized via controllable in-sire deposition and polymerization techniques using poly(styrene-co-acrylic) (PSA) latex as template.Field-dependent magnetization plot illustrates that the capsules are superparamagnetic at 300 K.FTIR spectrum confirms that the myoglobin (Mb) molecule adsorbed on the surface of Fe3O4/PPy hollow particle essentially retains its native structure.Furthermore,direct electrochemistry of Mb can be realized on Fe3O4/PPy capsules modified pyrolytic graphite disk electrode,which indicates that the magnetic conductive polymer capsules can promote the electron transfer of protein.
Monodispersed Fe3O4/polypyrrole (PPy) hollow particles were synthesized via controllable in-sire deposition and polymerization techniques using poly(styrene-co-acrylic) (PSA) latex as template.Field-dependent magnetization plot illustrates that the capsules are superparamagnetic at 300 K.FTIR spectrum confirms that the myoglobin (Mb) molecule adsorbed on the surface of Fe3O4/PPy hollow particle essentially retains its native structure.Furthermore,direct electrochemistry of Mb can be realized on Fe3O4/PPy capsules modified pyrolytic graphite disk electrode,which indicates that the magnetic conductive polymer capsules can promote the electron transfer of protein.
2008, 19(7): 881-884
doi: 10.1016/j.cclet.2008.04.039
Abstract:
The elimination of HBr from CH3Br by ground state of Cu+ and Au+ has been investigated by using DFT methods.A mechanism of one-step HBr elimination leading to CuCH2+ was identified.For the formation of AuCH2+,besides the one-step mechanism,another two-step HBr elimination pathway through a C-Br bond insertion intermediate was also found,and this pathway is energetically more favorable than the one-step mechanism.The calculated reaction energy barriers show that the formation of AuCH2+ is energetically much more favorable than the formation of CuCH2+.The experimental observations are well explained.
The elimination of HBr from CH3Br by ground state of Cu+ and Au+ has been investigated by using DFT methods.A mechanism of one-step HBr elimination leading to CuCH2+ was identified.For the formation of AuCH2+,besides the one-step mechanism,another two-step HBr elimination pathway through a C-Br bond insertion intermediate was also found,and this pathway is energetically more favorable than the one-step mechanism.The calculated reaction energy barriers show that the formation of AuCH2+ is energetically much more favorable than the formation of CuCH2+.The experimental observations are well explained.
