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2015 Volume 26 Issue 5
2015, 26(5): 491-498
doi: 10.1016/j.cclet.2015.03.038
Abstract:
This minireview describes the strategies for synthesis of fluorinated surfactants potentially nonbioaccumulable. Various strategies have been focused on (I) reducing the length of the perfluorocarbon chain, (II) introducing hetero atoms into the fluorocarbon chain, (III) introducing branch (herein and after branch means the fluoro-carbon chain section is not straight). In most cases, the surface tensions versus the surfactant concentrations have been assessed. These above strategies led to various highly fluorinated (perfluorinated or not perfluorinated) surfactants whose chemical changes enabled to obtain novel alternatives to perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS).
This minireview describes the strategies for synthesis of fluorinated surfactants potentially nonbioaccumulable. Various strategies have been focused on (I) reducing the length of the perfluorocarbon chain, (II) introducing hetero atoms into the fluorocarbon chain, (III) introducing branch (herein and after branch means the fluoro-carbon chain section is not straight). In most cases, the surface tensions versus the surfactant concentrations have been assessed. These above strategies led to various highly fluorinated (perfluorinated or not perfluorinated) surfactants whose chemical changes enabled to obtain novel alternatives to perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS).
2015, 26(5): 499-503
doi: 10.1016/j.cclet.2015.01.019
Abstract:
Two coordination polymers, {[Cu3(tci)2(DMAc)3]·6DMAc·2H2O}n (1) and {[Cu3(tci)2(tpt)2(H2O)2]·2DMAc·2H2O}n (2) (H3tci = tris(2-carboxyethyl)isocyanurate, tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine, DMAc = N,N-dimethylacetamide), have been constructed under solvothermal conditions. Both polymers were structurally characterized by single crystal X-ray diffraction, elemental analyses, IR spectra, thermogravimetric (TG) analyses and powder X-ray diffraction (RXPD). 1 shows a (3,4)-connected 2D layer structure comprising Cu2(CO2)4 paddle-wheel units, which are further bridged by C-H…O interactions to give a 3D supramolecular network. The introduction of tpt produces different framework for 2 that comprises a dinuclear and a mononuclear Cu(II) building units, which are further bridged together by tci3- and tpt ligands to give a 4-connected 2D topological net. Adjacent 2D layers are packed together via C-H…O interactions and π…π stacking interactions to form a 3D supramolecular structure. In addition, the luminescent properties and the solid-state UV-vis spectra of 1 and 2 were explored. Furthermore, antiferromagnetic exchange interactions were unveiled in the Cu2(COO)4 units of 1.
Two coordination polymers, {[Cu3(tci)2(DMAc)3]·6DMAc·2H2O}n (1) and {[Cu3(tci)2(tpt)2(H2O)2]·2DMAc·2H2O}n (2) (H3tci = tris(2-carboxyethyl)isocyanurate, tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine, DMAc = N,N-dimethylacetamide), have been constructed under solvothermal conditions. Both polymers were structurally characterized by single crystal X-ray diffraction, elemental analyses, IR spectra, thermogravimetric (TG) analyses and powder X-ray diffraction (RXPD). 1 shows a (3,4)-connected 2D layer structure comprising Cu2(CO2)4 paddle-wheel units, which are further bridged by C-H…O interactions to give a 3D supramolecular network. The introduction of tpt produces different framework for 2 that comprises a dinuclear and a mononuclear Cu(II) building units, which are further bridged together by tci3- and tpt ligands to give a 4-connected 2D topological net. Adjacent 2D layers are packed together via C-H…O interactions and π…π stacking interactions to form a 3D supramolecular structure. In addition, the luminescent properties and the solid-state UV-vis spectra of 1 and 2 were explored. Furthermore, antiferromagnetic exchange interactions were unveiled in the Cu2(COO)4 units of 1.
2015, 26(5): 504-508
doi: 10.1016/j.cclet.2015.01.020
Abstract:
Gel-incorporated single-crystals provide unique combinational properties of long-range order and composite structures, which is desired for semiconducting and conducting materials. However, the reported gel-incorporated single-crystals are limited to insulating crystals. Here, we examine crystals of two typical semiconductors, lead sulfide (PbS) and lead iodide (PbI2), grown from both silica gels and agarose gels. In all the four crystal-gel pairs, single-crystals of the cubic phase of PbS and the hexagonal phase of PbI2 were obtained according to the X-ray diffraction analysis. Dissolution of the gel-grown crystals exposed insoluble materials with the shape similar to the original crystals, indicative of gelincorporation inside the crystals. As such, this work creates a facile strategy to construct 3D heterostructures inside semiconducting single-crystals without destroying their long-range order.
Gel-incorporated single-crystals provide unique combinational properties of long-range order and composite structures, which is desired for semiconducting and conducting materials. However, the reported gel-incorporated single-crystals are limited to insulating crystals. Here, we examine crystals of two typical semiconductors, lead sulfide (PbS) and lead iodide (PbI2), grown from both silica gels and agarose gels. In all the four crystal-gel pairs, single-crystals of the cubic phase of PbS and the hexagonal phase of PbI2 were obtained according to the X-ray diffraction analysis. Dissolution of the gel-grown crystals exposed insoluble materials with the shape similar to the original crystals, indicative of gelincorporation inside the crystals. As such, this work creates a facile strategy to construct 3D heterostructures inside semiconducting single-crystals without destroying their long-range order.
2015, 26(5): 509-512
doi: 10.1016/j.cclet.2015.03.017
Abstract:
Chlorothiazole ring, as a substituted heterocycle, frequently occurred in structures of various insecticides, and brought positive effect on bioactivity. In purpose to find novel neonicotinoids, a series of pyrrole- and dihydropyrrole-fused neonicotinoid analogs containing chlorothiazole ring were synthesized for the first time. Results of the following biological assays showed that compounds 5a-c achieved good insecticidal activity against Aphis craccivora, and compound 5h exhibited good activity against Nilaparvata lugens.
Chlorothiazole ring, as a substituted heterocycle, frequently occurred in structures of various insecticides, and brought positive effect on bioactivity. In purpose to find novel neonicotinoids, a series of pyrrole- and dihydropyrrole-fused neonicotinoid analogs containing chlorothiazole ring were synthesized for the first time. Results of the following biological assays showed that compounds 5a-c achieved good insecticidal activity against Aphis craccivora, and compound 5h exhibited good activity against Nilaparvata lugens.
2015, 26(5): 513-516
doi: 10.1016/j.cclet.2015.01.023
Abstract:
Aminopeptidase N (APN) is an important drug target and biomarker for various tumors. The current work characterizes a novel APN-targeted fluorescent probe (Bes-Green, 2) that manifests comparable inhibitory activity with Bestatin. This probe has capacity of tightly binding to the APN for imaging endogenous APN in living human ovarian clear cell carcinoma cells (ES-2) and has potential application in biological study of cellular APN.
Aminopeptidase N (APN) is an important drug target and biomarker for various tumors. The current work characterizes a novel APN-targeted fluorescent probe (Bes-Green, 2) that manifests comparable inhibitory activity with Bestatin. This probe has capacity of tightly binding to the APN for imaging endogenous APN in living human ovarian clear cell carcinoma cells (ES-2) and has potential application in biological study of cellular APN.
2015, 26(5): 517-521
doi: 10.1016/j.cclet.2014.11.035
Abstract:
Two new homosecoiridoids, named loniaceticiridoside (1) and lonimalondialiridoside (2), were isolated from an aqueous extract of the flower buds of Lonicera japonica. Their structures including the absolute configuration were determined by extensive spectroscopic studies, especially by 2D NMR and CD data analysis. A proposed biosynthetic pathway and preliminary investigations of the biological activity of compounds 1 and 2 are also discussed.
Two new homosecoiridoids, named loniaceticiridoside (1) and lonimalondialiridoside (2), were isolated from an aqueous extract of the flower buds of Lonicera japonica. Their structures including the absolute configuration were determined by extensive spectroscopic studies, especially by 2D NMR and CD data analysis. A proposed biosynthetic pathway and preliminary investigations of the biological activity of compounds 1 and 2 are also discussed.
2015, 26(5): 522-528
doi: 10.1016/j.cclet.2015.01.025
Abstract:
Composites of a nickel based compound incorporated with graphene sheets (NiBC-GS) are prepared by a simple flocculation, using hydrazine hydrate as flocculant and reductant, from a homogeneous intermixture of nickel dichloride and graphene oxide dispersed in N,N-dimethylformamide. Morphology, microstructure and thermal stability of the obtained products were characterized by field-emission scanning electron microscopy, X-ray diffraction and thermal gravimetric analysis. Furthermore, the electrochemical properties of NiBC-GS, as electrodematerials for supercapacitors, were studied by cyclic voltammetry and galvanostatic charge/discharge in 2 mol L-1 KOH solution. It was determined that for NiBC-GS annealed at 250 8C, a high specific capacitance of 2394 F g-1 was achieved at a current density of 1 A g-1, with 78% of the value (i.e., 1864 F g-1) retained after 5000 times of repeated galvanostatic charge/discharge cycling. The high specific capacitance and available charge/discharge stability indicate the synthesized NiBC-GS250 composite is a good candidate as a novel electrode material for supercapacitors.
Composites of a nickel based compound incorporated with graphene sheets (NiBC-GS) are prepared by a simple flocculation, using hydrazine hydrate as flocculant and reductant, from a homogeneous intermixture of nickel dichloride and graphene oxide dispersed in N,N-dimethylformamide. Morphology, microstructure and thermal stability of the obtained products were characterized by field-emission scanning electron microscopy, X-ray diffraction and thermal gravimetric analysis. Furthermore, the electrochemical properties of NiBC-GS, as electrodematerials for supercapacitors, were studied by cyclic voltammetry and galvanostatic charge/discharge in 2 mol L-1 KOH solution. It was determined that for NiBC-GS annealed at 250 8C, a high specific capacitance of 2394 F g-1 was achieved at a current density of 1 A g-1, with 78% of the value (i.e., 1864 F g-1) retained after 5000 times of repeated galvanostatic charge/discharge cycling. The high specific capacitance and available charge/discharge stability indicate the synthesized NiBC-GS250 composite is a good candidate as a novel electrode material for supercapacitors.
2015, 26(5): 529-533
doi: 10.1016/j.cclet.2015.01.026
Abstract:
Tetrakis(alkoxycarbonyl)porphyrin and its β-octafluoro-substituted derivatives were synthesized via Lindsey method and transformed to their zinc complexes. Single crystal X-ray structures of corresponding Zn(II) porphyrins revealed that β-octafluorination will give more compactness of porphyrin moieties in the crystal structure owing to the hydrogen bonding interactions involving bfluorine atoms. An unusual six-coordinated Zn(II) was found via intramolecular coordination of oxygen atom of meso-substituents with central Zn(II).
Tetrakis(alkoxycarbonyl)porphyrin and its β-octafluoro-substituted derivatives were synthesized via Lindsey method and transformed to their zinc complexes. Single crystal X-ray structures of corresponding Zn(II) porphyrins revealed that β-octafluorination will give more compactness of porphyrin moieties in the crystal structure owing to the hydrogen bonding interactions involving bfluorine atoms. An unusual six-coordinated Zn(II) was found via intramolecular coordination of oxygen atom of meso-substituents with central Zn(II).
2015, 26(5): 534-538
doi: 10.1016/j.cclet.2015.01.006
Abstract:
A series of novel pyrazole fused heterocyclic derivatives were synthesized via a two-step procedure or a one-pot two step method, and their catalytic DNA cleavage abilities and anti-BVDV activities were also evaluated. The results obtained indicated that compounds 3b-3c could catalyze the cleavage of supercoiled DNA (pUC 19 plasmid DNA) to nicked DNA under physiological conditions with high yields via a hydrolytic mechanism. The studies on anti-viral activities against bovine viral diarrhea virus (BVDV) demonstrated that some of the pyrazole derivatives showed pronounced anti-BVDV activity with interesting EC50 values and no significant cytotoxicity. Among them, compound 3l showed the highest antiviral activity (EC50 = 0.12 μmol/L) and was 10 fold more than that of the positive control ribavirin (EC50 = 1.3 μmol/L), which provided a potential candidate for the development of anti-BVDV agents.
A series of novel pyrazole fused heterocyclic derivatives were synthesized via a two-step procedure or a one-pot two step method, and their catalytic DNA cleavage abilities and anti-BVDV activities were also evaluated. The results obtained indicated that compounds 3b-3c could catalyze the cleavage of supercoiled DNA (pUC 19 plasmid DNA) to nicked DNA under physiological conditions with high yields via a hydrolytic mechanism. The studies on anti-viral activities against bovine viral diarrhea virus (BVDV) demonstrated that some of the pyrazole derivatives showed pronounced anti-BVDV activity with interesting EC50 values and no significant cytotoxicity. Among them, compound 3l showed the highest antiviral activity (EC50 = 0.12 μmol/L) and was 10 fold more than that of the positive control ribavirin (EC50 = 1.3 μmol/L), which provided a potential candidate for the development of anti-BVDV agents.
2015, 26(5): 539-542
doi: 10.1016/j.cclet.2014.12.010
Abstract:
Selective oxidation of sulfides to sulfoxides was successfully performed by employing readily available Fe(NO3)3·9H2O as the active catalyst with oxygen as the oxidant in 2,2,2-trifluoroethanol (TFE) without the formation of sulfones. Nitrate anion could play a crucial role in promoting the reaction due to the oxidation capacity under acidic media. High yields of sulfoxides were exclusively obtained from the corresponding sulfides. Furthermore, both aromatic and aliphatic sulfides gave moderate to high yields of sulfoxides with this protocol.
Selective oxidation of sulfides to sulfoxides was successfully performed by employing readily available Fe(NO3)3·9H2O as the active catalyst with oxygen as the oxidant in 2,2,2-trifluoroethanol (TFE) without the formation of sulfones. Nitrate anion could play a crucial role in promoting the reaction due to the oxidation capacity under acidic media. High yields of sulfoxides were exclusively obtained from the corresponding sulfides. Furthermore, both aromatic and aliphatic sulfides gave moderate to high yields of sulfoxides with this protocol.
2015, 26(5): 543-546
doi: 10.1016/j.cclet.2015.01.005
Abstract:
In an organic phase system, an enzymes lipase was used as a catalyst to synthesize galactosylated cholesterol, (5-cholesten-3b-yl)[(4-O-β-D-galactopyranosyl)D-glucitol-6] sebacate (CHS-SE-LA), which contains galactose residues. Its chemical structure was characterized by ESI-MS, and NMR. For HepG2 cells, the cellular fluorescence intensities of liposomes modified with CHS-SE-LA (GAL-FL) were as much as 2.6-fold (p < 0.01) control liposomes (FL). Moreover, the presence of excess galactose significantly inhibited the uptake of GAL-FL suggesting ASGPR mediated uptake. In conclusion, the novel galactosylated ligand CHS-SE-LA was synthesized by lipase-catalyzation and revealed a great potential as drug carrier materials for hepatocyte-selective targeting.
In an organic phase system, an enzymes lipase was used as a catalyst to synthesize galactosylated cholesterol, (5-cholesten-3b-yl)[(4-O-β-D-galactopyranosyl)D-glucitol-6] sebacate (CHS-SE-LA), which contains galactose residues. Its chemical structure was characterized by ESI-MS, and NMR. For HepG2 cells, the cellular fluorescence intensities of liposomes modified with CHS-SE-LA (GAL-FL) were as much as 2.6-fold (p < 0.01) control liposomes (FL). Moreover, the presence of excess galactose significantly inhibited the uptake of GAL-FL suggesting ASGPR mediated uptake. In conclusion, the novel galactosylated ligand CHS-SE-LA was synthesized by lipase-catalyzation and revealed a great potential as drug carrier materials for hepatocyte-selective targeting.
2015, 26(5): 547-552
doi: 10.1016/j.cclet.2015.01.007
Abstract:
A new method employing magnetic nanoparticles Fe3O4 as a catalyst and H2O2 as a green oxidant is developed for the oxidative thiocyanation of aromatic amines, anisols and activated phenols with high yields under mild reaction conditions. The catalyst could be easily recovered from the reaction mixture using an external magnet and reused in several reaction cycles without loss of activity.
A new method employing magnetic nanoparticles Fe3O4 as a catalyst and H2O2 as a green oxidant is developed for the oxidative thiocyanation of aromatic amines, anisols and activated phenols with high yields under mild reaction conditions. The catalyst could be easily recovered from the reaction mixture using an external magnet and reused in several reaction cycles without loss of activity.
2015, 26(5): 553-556
doi: 10.1016/j.cclet.2014.12.013
Abstract:
Accepted theories predict that substitution reactions are controlled by the electronic nature of the attacked site for electrophilic aromatic substitution. Here it is shown that in addition the bond strength of the broken bond may also influence the regioselectivity of the substitution reaction, and that the Dpb is a good indicator of the strength of a chemical bond. The Dpb denotes the depth of the potential acting on one electron in amolecule at the bond center (bc). In this letter, the values of Dpb along the C-H and N-H bonds have been investigated, and it is demonstrated that for aromatic compounds, the regioselectivity of the electrophilic substitution can well be rationalized in terms of Dpb values.
Accepted theories predict that substitution reactions are controlled by the electronic nature of the attacked site for electrophilic aromatic substitution. Here it is shown that in addition the bond strength of the broken bond may also influence the regioselectivity of the substitution reaction, and that the Dpb is a good indicator of the strength of a chemical bond. The Dpb denotes the depth of the potential acting on one electron in amolecule at the bond center (bc). In this letter, the values of Dpb along the C-H and N-H bonds have been investigated, and it is demonstrated that for aromatic compounds, the regioselectivity of the electrophilic substitution can well be rationalized in terms of Dpb values.
2015, 26(5): 557-563
doi: 10.1016/j.cclet.2014.12.007
Abstract:
In the present work, the highly efficient Erlenmeyer synthesis of azlactones catalyzed by 2- aminopyridine, supported on nano-sphere SiO2 is reported. First, the silica nanoparticles were modified with triethoxysilylpropyl chloride and then 2-aminopyridine was attached to the support via covalent linkages. This new heterogenized catalyst was used for efficient microwave-assisted synthesis of azlactone derivatives with Ac2O as a condensing agent under solvent-free conditions. The present method offers advantages including high yields, short reaction times and simple work-up. Also, the catalyst can be easily recycled and reused several times, which makes this method attractive, economic and environmentally-benign.
In the present work, the highly efficient Erlenmeyer synthesis of azlactones catalyzed by 2- aminopyridine, supported on nano-sphere SiO2 is reported. First, the silica nanoparticles were modified with triethoxysilylpropyl chloride and then 2-aminopyridine was attached to the support via covalent linkages. This new heterogenized catalyst was used for efficient microwave-assisted synthesis of azlactone derivatives with Ac2O as a condensing agent under solvent-free conditions. The present method offers advantages including high yields, short reaction times and simple work-up. Also, the catalyst can be easily recycled and reused several times, which makes this method attractive, economic and environmentally-benign.
2015, 26(5): 564-566
doi: 10.1016/j.cclet.2014.12.017
Abstract:
Computational calculation was performed to investigate the mechanism of trifluoromethylation reactions of iodobenzene with well-defined N-heterocyclic carbene (NHC)-supported CuI trifluoromethyl complexes. Four proposed reaction pathways, namely σ-bond metathesis (BM), concerted oxidative addition-reductive elimination (OARE), iodine atomtransfer (IAT) and single-electron transfer (SET), have been computed by density functional theory (DFT). The result indicated that the concerted OARE mechanism is favored among the four reaction pathways, suggesting the trifluoromethylation may occur via concerted OARE mechanism involving Ar-X oxidative addition to the Cu(I) center as the rate determining step.
Computational calculation was performed to investigate the mechanism of trifluoromethylation reactions of iodobenzene with well-defined N-heterocyclic carbene (NHC)-supported CuI trifluoromethyl complexes. Four proposed reaction pathways, namely σ-bond metathesis (BM), concerted oxidative addition-reductive elimination (OARE), iodine atomtransfer (IAT) and single-electron transfer (SET), have been computed by density functional theory (DFT). The result indicated that the concerted OARE mechanism is favored among the four reaction pathways, suggesting the trifluoromethylation may occur via concerted OARE mechanism involving Ar-X oxidative addition to the Cu(I) center as the rate determining step.
2015, 26(5): 567-571
doi: 10.1016/j.cclet.2015.01.008
Abstract:
A series of indazol-2-yl(pyridin-4-yl)methanones, 4 were acquired from 2,6-bisbenzylidene cyclohexanones, 3 and anti-tubercular drug (isoniazid), and their anti-tubercular impacts were screened. Among the test compounds used against Mycobacterium tuberculosis H37 Ra cell line in the microplate alamar blue assay, the compounds 4g-j revealed moderate anti-tubercular activity with MIC 12.5 μg/mL, comparable to standard drugs (streptomycin, MIC, 6.25 μg/mL, pyrazinamide, isoniazid and ciprofloxacin with MICs of 3.125 μg/mL).
A series of indazol-2-yl(pyridin-4-yl)methanones, 4 were acquired from 2,6-bisbenzylidene cyclohexanones, 3 and anti-tubercular drug (isoniazid), and their anti-tubercular impacts were screened. Among the test compounds used against Mycobacterium tuberculosis H37 Ra cell line in the microplate alamar blue assay, the compounds 4g-j revealed moderate anti-tubercular activity with MIC 12.5 μg/mL, comparable to standard drugs (streptomycin, MIC, 6.25 μg/mL, pyrazinamide, isoniazid and ciprofloxacin with MICs of 3.125 μg/mL).
2015, 26(5): 572-574
doi: 10.1016/j.cclet.2015.01.011
Abstract:
With the natural rosin derivative (maleopimaric acid, MPA) as the raw material, imide modified vinyl poly(dimethylsiloxane) (MP-VMS) was synthesized and characterized by 1H NMR and 13C NMR. The curing kinetic parameters of MP-VMS were determined by differential scanning calorimetry (DSC) at various heating rates (5, 8, 10, 15 ℃/min) from the Kissingner, Ozawa and Crane methods. The activation energy (Ea), pre-exponential factor (A) and reaction order (n) were respectively 18.6 kJ/mol, 71,108 and 0.902. The low-temperature and high-temperature resistance of its curing product were respectively investigated by DSC and thermogravimetric analysis. The results showed that incorporation of MPA could significantly improve the thermal stability of silicone while had no effect on the low-temperature resistance, and the Tmax (the temperature corresponding to themaximum weight loss rate) increased by 70.7 ℃.
With the natural rosin derivative (maleopimaric acid, MPA) as the raw material, imide modified vinyl poly(dimethylsiloxane) (MP-VMS) was synthesized and characterized by 1H NMR and 13C NMR. The curing kinetic parameters of MP-VMS were determined by differential scanning calorimetry (DSC) at various heating rates (5, 8, 10, 15 ℃/min) from the Kissingner, Ozawa and Crane methods. The activation energy (Ea), pre-exponential factor (A) and reaction order (n) were respectively 18.6 kJ/mol, 71,108 and 0.902. The low-temperature and high-temperature resistance of its curing product were respectively investigated by DSC and thermogravimetric analysis. The results showed that incorporation of MPA could significantly improve the thermal stability of silicone while had no effect on the low-temperature resistance, and the Tmax (the temperature corresponding to themaximum weight loss rate) increased by 70.7 ℃.
2015, 26(5): 575-579
doi: 10.1016/j.cclet.2015.01.033
Abstract:
Cesium carbonate supported on hydroxyapatite coated Ni0.5Zn0.5Fe2O4 magnetic nanoparticles (Ni0.5Zn0.5Fe2O4@Hap-Cs2CO3) was found to be magnetically separable, highly efficient, green and recyclable heterogeneous catalyst. The synthesized nanocatalyst has been characterized with several methods (FT-IR, SEM, TEM, XRD and XRF) and these analyzes confirmed which the cesium carbonate is well supported to catalyst surface. After full characterization, its catalytic activity was investigated in the synthesis of pyranopyrazole derivatives and the reactions were carried out at room temperature in 50:50 water/ethanol with excellent yields (88-95%). More importantly, the Ni0.5Zn0.5Fe2O4@Hap-Cs2CO3 was easily separated from the reaction mixture by external magnetic field and efficiently reused at least six runs without any loss of its catalytic activity. Thus, the developed nanomagnetic base catalyst is potentially useful for the green and economic production of organic compounds.
Cesium carbonate supported on hydroxyapatite coated Ni0.5Zn0.5Fe2O4 magnetic nanoparticles (Ni0.5Zn0.5Fe2O4@Hap-Cs2CO3) was found to be magnetically separable, highly efficient, green and recyclable heterogeneous catalyst. The synthesized nanocatalyst has been characterized with several methods (FT-IR, SEM, TEM, XRD and XRF) and these analyzes confirmed which the cesium carbonate is well supported to catalyst surface. After full characterization, its catalytic activity was investigated in the synthesis of pyranopyrazole derivatives and the reactions were carried out at room temperature in 50:50 water/ethanol with excellent yields (88-95%). More importantly, the Ni0.5Zn0.5Fe2O4@Hap-Cs2CO3 was easily separated from the reaction mixture by external magnetic field and efficiently reused at least six runs without any loss of its catalytic activity. Thus, the developed nanomagnetic base catalyst is potentially useful for the green and economic production of organic compounds.
2015, 26(5): 580-584
doi: 10.1016/j.cclet.2014.11.031
Abstract:
A dual colorimetric and luminescent sensor based on a heteroleptic ruthenium dye [Ru(Hipdpa)(Hdcbpy)(NCS)2]-·0.5H+0.5[N(C4H9)4]+ Ru(Hipdpa) {where Hdcbpy = monodeprotonted-4,4'-dicarboxy-2,2'- bipyridine and Hipdpa = 4-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)-N,N-diphenylaniline} for selective detection of Hg2+ is presented. The results of spectrophotometric titrations revealed an evident luminescence intensity enhancement (I/I0 = 11) and a considerable blue shift in visible absorption and luminescence maxima with the addition of Hg2+. The sensitive response of the optical sensor on Hg2+ was attributed to the binding of the electron-deficient Hg2+ to the electron-rich sulfur atom of the thiocyanate (NCS) ligand in the Ru(Hipdpa), which led to an increase in the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). Accordingly, the blue shift in the absorption spectrum of Ru(Hipdpa) due to the binding of Hg2+ was obtained. Ru(Hipdpa) was found to have decreased Hg2+ detection limit and improved linear region as compared to di(tetrabutylammonium) cis-bis(isothiocyanato)bis(2,2'-bipyridine-4-carboxylic acid-4'- carboxylate)ruthenium(II) N719. Moreover, a dramatic color change from pink to yellow was observed, which allowed simple monitoring of Hg2+ by either naked eyes or a simple colorimetric reader. Therefore, the proposed sensor can provide potential applications for Hg2+ detection.
A dual colorimetric and luminescent sensor based on a heteroleptic ruthenium dye [Ru(Hipdpa)(Hdcbpy)(NCS)2]-·0.5H+0.5[N(C4H9)4]+ Ru(Hipdpa) {where Hdcbpy = monodeprotonted-4,4'-dicarboxy-2,2'- bipyridine and Hipdpa = 4-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)-N,N-diphenylaniline} for selective detection of Hg2+ is presented. The results of spectrophotometric titrations revealed an evident luminescence intensity enhancement (I/I0 = 11) and a considerable blue shift in visible absorption and luminescence maxima with the addition of Hg2+. The sensitive response of the optical sensor on Hg2+ was attributed to the binding of the electron-deficient Hg2+ to the electron-rich sulfur atom of the thiocyanate (NCS) ligand in the Ru(Hipdpa), which led to an increase in the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). Accordingly, the blue shift in the absorption spectrum of Ru(Hipdpa) due to the binding of Hg2+ was obtained. Ru(Hipdpa) was found to have decreased Hg2+ detection limit and improved linear region as compared to di(tetrabutylammonium) cis-bis(isothiocyanato)bis(2,2'-bipyridine-4-carboxylic acid-4'- carboxylate)ruthenium(II) N719. Moreover, a dramatic color change from pink to yellow was observed, which allowed simple monitoring of Hg2+ by either naked eyes or a simple colorimetric reader. Therefore, the proposed sensor can provide potential applications for Hg2+ detection.
2015, 26(5): 585-589
doi: 10.1016/j.cclet.2014.11.033
Abstract:
Two new secodammarane triterpenoid saponins, cyclocariosides I and J (1 and 2), and a new epoxydammarane triterpenoid saponin, cyclocarioside K (3) were isolated from the ethanol extracts of the leaves of Cyclocarya paliurus. The structures of these compounds were elucidated by spectroscopic techniques.
Two new secodammarane triterpenoid saponins, cyclocariosides I and J (1 and 2), and a new epoxydammarane triterpenoid saponin, cyclocarioside K (3) were isolated from the ethanol extracts of the leaves of Cyclocarya paliurus. The structures of these compounds were elucidated by spectroscopic techniques.
2015, 26(5): 590-594
doi: 10.1016/j.cclet.2014.12.008
Abstract:
In this study, seven alkaloids were detected in Wu-tou decoction using ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MSn). The aim of this study was to investigate the effect of Fritillariae Cirrhosae Bulbus, Fritillariae Thunbergii Bulbus, Pinelliae Rhizoma in different ratios with Wu-tou decoction (2:1, 1:1, 1:2) by measuring the therapeutic effects in Wu-tou decoction of main seven alkaloids including benzoylaconitine (BA), benzoylmesaconitine (BM), benzoylhypaconitine (BH), hypaconitine (HA), fuziline (FU), niaolin (NE) and deoxyaconitine (DA). The permeability of aconitum alkaloids extract through a Caco-2 cell monolayer was analyzed in the absence and presence of Fritillariae Cirrhosae Bulbus, Fritillariae Thunbergii Bulbus, and Pinelliae Rhizoma, respectively. The results showed that Pinelliae Rhizoma could reduce the absorption of the alkaloids and increase the excretion of the alkaloids, which would attenuate the therapeutic effects of Wu-tou decoction. Therefore, Pinelliae Rhizoma is an incompatible herb of Wu-tou decoction because of the inhibition of the absorption of alkaloids in the intestine. And that Fritillariae Cirrhosae Bulbus and Fritillariae Thunbergii Bulbus showed the effects to improve the permeability of the alkaloids in Wu-tou decoction. These effects of these two herbs were similar, but the former was stronger than the latter, which most likely is due to the fact that the compositions of these two traditional Chinese medicines are similar. The in vitro data suggests that the compounds such as fritillary presented in alkaloids in the formula maybe improve the therapeutic function caused by the increased bioavailability of alkaloids in intestine.
In this study, seven alkaloids were detected in Wu-tou decoction using ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MSn). The aim of this study was to investigate the effect of Fritillariae Cirrhosae Bulbus, Fritillariae Thunbergii Bulbus, Pinelliae Rhizoma in different ratios with Wu-tou decoction (2:1, 1:1, 1:2) by measuring the therapeutic effects in Wu-tou decoction of main seven alkaloids including benzoylaconitine (BA), benzoylmesaconitine (BM), benzoylhypaconitine (BH), hypaconitine (HA), fuziline (FU), niaolin (NE) and deoxyaconitine (DA). The permeability of aconitum alkaloids extract through a Caco-2 cell monolayer was analyzed in the absence and presence of Fritillariae Cirrhosae Bulbus, Fritillariae Thunbergii Bulbus, and Pinelliae Rhizoma, respectively. The results showed that Pinelliae Rhizoma could reduce the absorption of the alkaloids and increase the excretion of the alkaloids, which would attenuate the therapeutic effects of Wu-tou decoction. Therefore, Pinelliae Rhizoma is an incompatible herb of Wu-tou decoction because of the inhibition of the absorption of alkaloids in the intestine. And that Fritillariae Cirrhosae Bulbus and Fritillariae Thunbergii Bulbus showed the effects to improve the permeability of the alkaloids in Wu-tou decoction. These effects of these two herbs were similar, but the former was stronger than the latter, which most likely is due to the fact that the compositions of these two traditional Chinese medicines are similar. The in vitro data suggests that the compounds such as fritillary presented in alkaloids in the formula maybe improve the therapeutic function caused by the increased bioavailability of alkaloids in intestine.
2015, 26(5): 595-598
doi: 10.1016/j.cclet.2014.12.011
Abstract:
Based on the generalized gradient approximation (GGA), Perdew-Wang-91 (PW91) combined with a periodic slab model has been applied to study the catalytic activity of chlorine evolution on TinRumO2(1 1 0) surface. Metal oxide model TinRumO2 has been established with pure TiO2 and RuO2 on the basis set of Double Numerical plus polarization (DNP), in which the proportion of n:m was 3:1, 1:1, or 1:3. Analysis on the reaction activity in the electrochemical reaction and the electrochemical desorption reaction was based on Frontiermolecular orbital theory. The results show that the TinRumO2 with a ratio of Ti:Ru at 3:1 is best facilitates the electrochemical reaction and electrochemical desorption reaction to produce M-Clads intermediate and precipitate Cl2. In addition, the adsorption energy of Cl on the surface of Ti3Ru1O2 possesses the minimum value of 2.514 eV, and thus electrochemical desorption reaction could occur most easily.
Based on the generalized gradient approximation (GGA), Perdew-Wang-91 (PW91) combined with a periodic slab model has been applied to study the catalytic activity of chlorine evolution on TinRumO2(1 1 0) surface. Metal oxide model TinRumO2 has been established with pure TiO2 and RuO2 on the basis set of Double Numerical plus polarization (DNP), in which the proportion of n:m was 3:1, 1:1, or 1:3. Analysis on the reaction activity in the electrochemical reaction and the electrochemical desorption reaction was based on Frontiermolecular orbital theory. The results show that the TinRumO2 with a ratio of Ti:Ru at 3:1 is best facilitates the electrochemical reaction and electrochemical desorption reaction to produce M-Clads intermediate and precipitate Cl2. In addition, the adsorption energy of Cl on the surface of Ti3Ru1O2 possesses the minimum value of 2.514 eV, and thus electrochemical desorption reaction could occur most easily.
2015, 26(5): 599-602
doi: 10.1016/j.cclet.2014.12.018
Abstract:
A method of C(sp3)-H bond functionalization of methyl azaarenes catalyzed by alumina-supported heteropoly acid and addition to isatins was developed. This transformation could be used for the synthesis of biologically important 3-hydroxy-2-oxindole derivatives in good to excellent yields and the catalyst could be reused for six times without significant decrease in activity.
A method of C(sp3)-H bond functionalization of methyl azaarenes catalyzed by alumina-supported heteropoly acid and addition to isatins was developed. This transformation could be used for the synthesis of biologically important 3-hydroxy-2-oxindole derivatives in good to excellent yields and the catalyst could be reused for six times without significant decrease in activity.
2015, 26(5): 603-606
doi: 10.1016/j.cclet.2015.01.009
Abstract:
Pentylpyridinium tribromide and aqueous ammonium acetate was used for the rapid oxidative conversion of benzyl alcohols, benzaldehydes and benzyl amines to the corresponding benzonitriles in good to excellent yields. This simple, mild and one-pot system provides easy workup and separation of the products.
Pentylpyridinium tribromide and aqueous ammonium acetate was used for the rapid oxidative conversion of benzyl alcohols, benzaldehydes and benzyl amines to the corresponding benzonitriles in good to excellent yields. This simple, mild and one-pot system provides easy workup and separation of the products.
2015, 26(5): 607-609
doi: 10.1016/j.cclet.2015.03.022
Abstract:
A series of new combretastatin-A4 analogs were synthesized, in which a six-membered ring connects the linking bridge and A ring, and their tumor cell growth and tubulin-polymerization inhibitory activity were evaluated. These compounds appear to be potential tubulin-polymerization inhibitors. Compounds 1b with amino substituted on position 3 of B ring conferred optimal bioactivity, higher than that of the lead compound 22b and equivalent to that of CA-4. The binding modes of these compounds to tubulin were obtained by molecular docking, which can explain the structure-activity relationship. The studies presented here provide a new structural type for the development of novel antitumor agents.
A series of new combretastatin-A4 analogs were synthesized, in which a six-membered ring connects the linking bridge and A ring, and their tumor cell growth and tubulin-polymerization inhibitory activity were evaluated. These compounds appear to be potential tubulin-polymerization inhibitors. Compounds 1b with amino substituted on position 3 of B ring conferred optimal bioactivity, higher than that of the lead compound 22b and equivalent to that of CA-4. The binding modes of these compounds to tubulin were obtained by molecular docking, which can explain the structure-activity relationship. The studies presented here provide a new structural type for the development of novel antitumor agents.
2015, 26(5): 610-612
doi: 10.1016/j.cclet.2015.01.024
Abstract:
A new polyoxygenated dihydropyrano[2,3-c]pyrrole-4,5-dione derivative, pyranonigrin F (1), together with a related known compound, pyranonigrin A (2), were isolated and identified from Penicillium brocae MA-231, an endophytic fungus obtained from the fresh tissue of the marine mangrove plant Avicennia marina. The structures of these metabolites were determined based on comprehensive spectral interpretation and the absolute configuration of compound 1 was established by X-ray crystallographic analysis. Compounds 1, and 2 showed potent activity against a broad spectrum of human-, aqua-, and plant-pathogens.
A new polyoxygenated dihydropyrano[2,3-c]pyrrole-4,5-dione derivative, pyranonigrin F (1), together with a related known compound, pyranonigrin A (2), were isolated and identified from Penicillium brocae MA-231, an endophytic fungus obtained from the fresh tissue of the marine mangrove plant Avicennia marina. The structures of these metabolites were determined based on comprehensive spectral interpretation and the absolute configuration of compound 1 was established by X-ray crystallographic analysis. Compounds 1, and 2 showed potent activity against a broad spectrum of human-, aqua-, and plant-pathogens.
2015, 26(5): 613-618
doi: 10.1016/j.cclet.2014.11.032
Abstract:
A simple and sensitive electroanalytical method for determination of shikonin, a widely used antitumoral agent, using β-cyclodextrin-functionalized multiwalled carbon nanotubes composite modified glassy carbon electrodes (MWCNTs/β-CD/GCE) was presented. CDs are water-soluble and environmentally friendly and can improve the dispersibility of MWCNTs/β-CD functional materials, which was confirmed by SEM. The electrochemical behaviors of shikonin on different electrodes were investigated by cyclic voltammetry (CV) and differential pulse voltammograms (DPVs). The results demonstrated that the redox peak currents of shikonin obtained at MWCNTs/β-CD/GCE were much higher than those at the β-CD/GCE and MWCNTs/GCE, which can be attributed to the combination of the excellent electrocatalytic properties of MWCNTs and the molecular recognition ability of β-CD. At MWCNTs/β-CD/GCE, the response current exhibits a linear range from 5.0 nmol/L to 10.0 μmol/L with a detection limit of 1.0 nmol/L (S/N = 3). As a practical application, the proposed method was applied to quantitatively determine shikoninin urine samples with satisfying results.
A simple and sensitive electroanalytical method for determination of shikonin, a widely used antitumoral agent, using β-cyclodextrin-functionalized multiwalled carbon nanotubes composite modified glassy carbon electrodes (MWCNTs/β-CD/GCE) was presented. CDs are water-soluble and environmentally friendly and can improve the dispersibility of MWCNTs/β-CD functional materials, which was confirmed by SEM. The electrochemical behaviors of shikonin on different electrodes were investigated by cyclic voltammetry (CV) and differential pulse voltammograms (DPVs). The results demonstrated that the redox peak currents of shikonin obtained at MWCNTs/β-CD/GCE were much higher than those at the β-CD/GCE and MWCNTs/GCE, which can be attributed to the combination of the excellent electrocatalytic properties of MWCNTs and the molecular recognition ability of β-CD. At MWCNTs/β-CD/GCE, the response current exhibits a linear range from 5.0 nmol/L to 10.0 μmol/L with a detection limit of 1.0 nmol/L (S/N = 3). As a practical application, the proposed method was applied to quantitatively determine shikoninin urine samples with satisfying results.
2015, 26(5): 619-622
doi: 10.1016/j.cclet.2015.01.010
Abstract:
We describe a specific procedure for the synthesis of deuterium-labelled 2-(1-methylalkyl)succinate established via alkylation of diethyl malonate, Krapcho decarboxylation reaction with D2O and hydrolysis reaction. Two novel compounds, 2-[2H]-2-ethylsuccinic acid and 2-[2H]-2-(1-methylheptyl) succinic acid were prepared via this synthetic route and characterized by mass spectrometry and 1H NMR. The results showed that the 2-(1-methylalkyl)succinic acids were deuterated at the β-position, which is considered as an important reaction centre in the anaerobic degradation of n-alkanes.
We describe a specific procedure for the synthesis of deuterium-labelled 2-(1-methylalkyl)succinate established via alkylation of diethyl malonate, Krapcho decarboxylation reaction with D2O and hydrolysis reaction. Two novel compounds, 2-[2H]-2-ethylsuccinic acid and 2-[2H]-2-(1-methylheptyl) succinic acid were prepared via this synthetic route and characterized by mass spectrometry and 1H NMR. The results showed that the 2-(1-methylalkyl)succinic acids were deuterated at the β-position, which is considered as an important reaction centre in the anaerobic degradation of n-alkanes.
2015, 26(5): 623-626
doi: 10.1016/j.cclet.2015.01.002
Abstract:
The synthesis of pyrazole derivatives from o-alkynylchalcones and hydrazine via simple cyclization is described. This greener syntheticmethodology provides a straightforward approach to the synthesis of a variety of pyrazole derivatives under mild reaction condition.
The synthesis of pyrazole derivatives from o-alkynylchalcones and hydrazine via simple cyclization is described. This greener syntheticmethodology provides a straightforward approach to the synthesis of a variety of pyrazole derivatives under mild reaction condition.
2015, 26(5): 627-630
doi: 10.1016/j.cclet.2015.01.022
Abstract:
A series of novel phenothiazine derivatives was synthesized and tested for arginine vasopressin receptor antagonist activity. They were synthesized as novel arginine vasopressin receptor antagonists from phenothiazine as a scaffold via successive acylation, reduction and acylation reactions. Their structures were characterized by 1HNMR, 13CNMRandHRMS, and biological activitywas evaluated by in vitro and in vivo studies. The in vitro binding assay indicated that several compounds are potent selective V2 receptor antagonists. Compounds with promising binding affinity to V2 receptors were selected to conduct the in vivo diuretic studies on Sprague-Dawley rats. Among them, 1n, 1r, 1t and 1v exhibited excellent diuretic activity, especially 1r and 1v. Therefore, 1r and 1v are potent novelAVP V2receptor antagonist candidates.
A series of novel phenothiazine derivatives was synthesized and tested for arginine vasopressin receptor antagonist activity. They were synthesized as novel arginine vasopressin receptor antagonists from phenothiazine as a scaffold via successive acylation, reduction and acylation reactions. Their structures were characterized by 1HNMR, 13CNMRandHRMS, and biological activitywas evaluated by in vitro and in vivo studies. The in vitro binding assay indicated that several compounds are potent selective V2 receptor antagonists. Compounds with promising binding affinity to V2 receptors were selected to conduct the in vivo diuretic studies on Sprague-Dawley rats. Among them, 1n, 1r, 1t and 1v exhibited excellent diuretic activity, especially 1r and 1v. Therefore, 1r and 1v are potent novelAVP V2receptor antagonist candidates.
