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2015 Volume 26 Issue 10
2015, 26(10): 1197-1197
doi: 10.1016/j.cclet.2015.09.014
Abstract:
2015, 26(10): 1198-1202
doi: 10.1016/j.cclet.2015.08.006
Abstract:
Self-similar fractals are of importance in both science and engineering. Metal-organic Sierpiński triangles are particularly attractive for applications in gas separation, catalysis and sensing. Such fractals are constructed in this study by using 120° V-shaped 4, 4"-dicyano-1, 1':3', 1"-terphenyl molecules and Fe atoms on Au(1 1 1), and studied in detail by low-temperature scanning tunneling microscopy. Density functional theory calculations are employed to rationalize the invisible Fe atoms in STM images. Monte Carlo simulations are performed to understand the formation mechanism of the surface-supported fractal crystals.
Self-similar fractals are of importance in both science and engineering. Metal-organic Sierpiński triangles are particularly attractive for applications in gas separation, catalysis and sensing. Such fractals are constructed in this study by using 120° V-shaped 4, 4"-dicyano-1, 1':3', 1"-terphenyl molecules and Fe atoms on Au(1 1 1), and studied in detail by low-temperature scanning tunneling microscopy. Density functional theory calculations are employed to rationalize the invisible Fe atoms in STM images. Monte Carlo simulations are performed to understand the formation mechanism of the surface-supported fractal crystals.
2015, 26(10): 1203-1208
doi: 10.1016/j.cclet.2015.08.005
Abstract:
A pH-sensitive controlled release system was proposed in this work, which consists of mesoporous silica nanoparticles (MSNs) functionalized on the pore outlets with poly(4-vinylphenybronic acid-co-2- (dimethylamino)ethyl acrylate) [P(VPBA-DMAEA)]. Four kinds of P(VPBA-DMAEA)-gated MSNs were synthesized and applied for the pH-sensitive controlled release. The results showed that P(VPBADMAEA) can work as a pH-sensitive nanovalve. The release behavior of the hybrid nanoparticles could be adjusted by changing the mole ratio of VPBA and DMAEA. With the increasing of the mole ratio of VPBA, the leakage of the entrapped molecules in the pores of MSNs could be decreased at neutral and alkaline conditions. By altering the pH of buffer from 4.0 to 8.0, the valve could be switched "on" and "off" reversibly. In addition, cells viability results indicated that these P(VPBA-DMAEA)-gated MSNs had good biocompatibility. We believe that these MSNs based pH-sensitive controlled release system will provide a promising nanodevice for sited release of drug delivery.
A pH-sensitive controlled release system was proposed in this work, which consists of mesoporous silica nanoparticles (MSNs) functionalized on the pore outlets with poly(4-vinylphenybronic acid-co-2- (dimethylamino)ethyl acrylate) [P(VPBA-DMAEA)]. Four kinds of P(VPBA-DMAEA)-gated MSNs were synthesized and applied for the pH-sensitive controlled release. The results showed that P(VPBADMAEA) can work as a pH-sensitive nanovalve. The release behavior of the hybrid nanoparticles could be adjusted by changing the mole ratio of VPBA and DMAEA. With the increasing of the mole ratio of VPBA, the leakage of the entrapped molecules in the pores of MSNs could be decreased at neutral and alkaline conditions. By altering the pH of buffer from 4.0 to 8.0, the valve could be switched "on" and "off" reversibly. In addition, cells viability results indicated that these P(VPBA-DMAEA)-gated MSNs had good biocompatibility. We believe that these MSNs based pH-sensitive controlled release system will provide a promising nanodevice for sited release of drug delivery.
2015, 26(10): 1209-1215
doi: 10.1016/j.cclet.2015.07.023
Abstract:
Asymmetric total synthesis of emericellamide B (9.4%, 17 longest linear steps) is detailed in this report. In this synthetic route, the highly methylated (2R, 3R, 4S, 6S)-3-hydroxy-2, 4, 6-trimethyldodecanoic acid (HTMD) unit was effectively prepared through the asymmetric methylation, Wittig and Horner- Wadsworth-Emmons reaction. Moreover, pentafluorophenyl diphenylphophinate (FDPP) proved to be an effective condensation reagent for the macrolactamization between C14 and C18.
Asymmetric total synthesis of emericellamide B (9.4%, 17 longest linear steps) is detailed in this report. In this synthetic route, the highly methylated (2R, 3R, 4S, 6S)-3-hydroxy-2, 4, 6-trimethyldodecanoic acid (HTMD) unit was effectively prepared through the asymmetric methylation, Wittig and Horner- Wadsworth-Emmons reaction. Moreover, pentafluorophenyl diphenylphophinate (FDPP) proved to be an effective condensation reagent for the macrolactamization between C14 and C18.
2015, 26(10): 1216-1220
doi: 10.1016/j.cclet.2015.07.008
Abstract:
A novel copper-catalyzed dual oxidative benzylic C-H aminations of methylarenes with 2- aminobenzoketones in the presence of ammonium acetate was developed. This reaction represents a new avenue for 2-arylquinazolines with good yields. A key intermediate was detected and the kinetics isotope effect (KIE) indicated that C-H bond cleavage was the rate-determining step.
A novel copper-catalyzed dual oxidative benzylic C-H aminations of methylarenes with 2- aminobenzoketones in the presence of ammonium acetate was developed. This reaction represents a new avenue for 2-arylquinazolines with good yields. A key intermediate was detected and the kinetics isotope effect (KIE) indicated that C-H bond cleavage was the rate-determining step.
2015, 26(10): 1221-1224
doi: 10.1016/j.cclet.2015.07.019
Abstract:
Shape-memory poly(p-dioxanone)-poly(ε-caprolactone)/sepiolite (PPDO-PCL/OSEP) nanocomposites with different OSEP nanofiber loading were fabricated by chain-extending the PPDO-diol and PCL/OSEP precursors. The precursors and the composites were characterized by 1H NMR, FT-IR, GPC, SEM and TEM. The results demonstrate that a part of PCL segments grafted on the surface of OSEP and composites display a fine dispersion of OSEP fiber in nanoscale with low OSEP content. The shape memory effect (SME) was evaluated by DMA, the results reveal that the PPDO-PCL/OSEP nanocomposites exhibit desirable shape-memory performance. The reinforcement of composites by incorporation of trace OSEP nanofiber evokes an effective improvement in shape-memory recovery stress.
Shape-memory poly(p-dioxanone)-poly(ε-caprolactone)/sepiolite (PPDO-PCL/OSEP) nanocomposites with different OSEP nanofiber loading were fabricated by chain-extending the PPDO-diol and PCL/OSEP precursors. The precursors and the composites were characterized by 1H NMR, FT-IR, GPC, SEM and TEM. The results demonstrate that a part of PCL segments grafted on the surface of OSEP and composites display a fine dispersion of OSEP fiber in nanoscale with low OSEP content. The shape memory effect (SME) was evaluated by DMA, the results reveal that the PPDO-PCL/OSEP nanocomposites exhibit desirable shape-memory performance. The reinforcement of composites by incorporation of trace OSEP nanofiber evokes an effective improvement in shape-memory recovery stress.
2015, 26(10): 1225-1230
doi: 10.1016/j.cclet.2015.03.007
Abstract:
Glioma stem cells are considered responsible for drug resistance and glioma relapse resulting in poor prognosis in glioblastomamultiforme. SU3 glioma cell is a highly invasive glioma stemcell line from the patients with glioblastoma multifrome. It is of great significance to study the efficacy and molecular mechanism for anticancer drug effects on SU3 glioma cells. In this work, we develop a liquid chromatography-mass spectrometry (LC-MS) method for direct analysis of the role of drugs (paclitaxel) on SU3 glioma cells at themolecular level. Weuse the specific fluorescence dyes to evaluate cell viability, the levels of ROS and GSH when the cells were treated with drugs. In addition, the LC-MS platform was successfully employed to detect the amount of 6-O-methylguanine, demonstrating that it is effective to induce cell apoptosis and enhance the cytotoxic response of SU3 glioma cells. The analytical linear equals are Y=9.49×105X+2.42×104 for 6-O-methylguanine (R2=0.9998) and Y=4.72×104X+2.21×103(R2=0.9996) for 7-methylguanine. Thus, the combination of cell-specific fluorescence dyes and LC-MS method enables us to reveal the molecular mechanism of paclitaxel-inhibited growth and enhanced therapeutic response in the chemotherapy for glioma multiforme.
Glioma stem cells are considered responsible for drug resistance and glioma relapse resulting in poor prognosis in glioblastomamultiforme. SU3 glioma cell is a highly invasive glioma stemcell line from the patients with glioblastoma multifrome. It is of great significance to study the efficacy and molecular mechanism for anticancer drug effects on SU3 glioma cells. In this work, we develop a liquid chromatography-mass spectrometry (LC-MS) method for direct analysis of the role of drugs (paclitaxel) on SU3 glioma cells at themolecular level. Weuse the specific fluorescence dyes to evaluate cell viability, the levels of ROS and GSH when the cells were treated with drugs. In addition, the LC-MS platform was successfully employed to detect the amount of 6-O-methylguanine, demonstrating that it is effective to induce cell apoptosis and enhance the cytotoxic response of SU3 glioma cells. The analytical linear equals are Y=9.49×105X+2.42×104 for 6-O-methylguanine (R2=0.9998) and Y=4.72×104X+2.21×103(R2=0.9996) for 7-methylguanine. Thus, the combination of cell-specific fluorescence dyes and LC-MS method enables us to reveal the molecular mechanism of paclitaxel-inhibited growth and enhanced therapeutic response in the chemotherapy for glioma multiforme.
2015, 26(10): 1231-1235
doi: 10.1016/j.cclet.2015.07.022
Abstract:
The coupling reactions of simple methyl ketones with o-bromoacetophenones and subsquential cyclization reactions were realized to produce a range of 1-naphthols. These cascade reactions were initiated by a rare Cu-catalyzed arylation reaction of methyl ketones with aromatic bromides.
The coupling reactions of simple methyl ketones with o-bromoacetophenones and subsquential cyclization reactions were realized to produce a range of 1-naphthols. These cascade reactions were initiated by a rare Cu-catalyzed arylation reaction of methyl ketones with aromatic bromides.
2015, 26(10): 1236-1240
doi: 10.1016/j.cclet.2015.07.011
Abstract:
A palladium-catalyzed ortho-selective C-H bond chlorination reaction for the preparation of 2-chloro aromatic ketones was described. Both electron-withdrawing and electron-donating groups on the aromatic rings are well tolerated under the optimized conditions. The 2-chloro aromatic ketones obtained by our method could be applied to synthesize the derivatives of 1H-indazole or benzo[d]isoxazole.
A palladium-catalyzed ortho-selective C-H bond chlorination reaction for the preparation of 2-chloro aromatic ketones was described. Both electron-withdrawing and electron-donating groups on the aromatic rings are well tolerated under the optimized conditions. The 2-chloro aromatic ketones obtained by our method could be applied to synthesize the derivatives of 1H-indazole or benzo[d]isoxazole.
2015, 26(10): 1241-1245
doi: 10.1016/j.cclet.2015.07.002
Abstract:
The phosphorus-containing PODIPY 1 as a chemosensor can detect Hg2+ by a color change from pink to violet red without the use of any instrumentation. PODIPY 1 was selective to Hg2+ with a remarkable absorption change, and addition of other relevant metal ions caused almost no absorption change. The new PODIPY dye 1 was sensitive to various concentrations of Hg2+. The energy gap between the HOMO and LUMO of the metal complex 1-Hg2+ is smaller than that of chemosensor 1, which is in good agreement with the red shift in the absorption observed upon treatment of 1 with Hg2+. The 1-based test strips were easily fabricated and low-cost, useful in practical and efficient Hg2+ test kits.
The phosphorus-containing PODIPY 1 as a chemosensor can detect Hg2+ by a color change from pink to violet red without the use of any instrumentation. PODIPY 1 was selective to Hg2+ with a remarkable absorption change, and addition of other relevant metal ions caused almost no absorption change. The new PODIPY dye 1 was sensitive to various concentrations of Hg2+. The energy gap between the HOMO and LUMO of the metal complex 1-Hg2+ is smaller than that of chemosensor 1, which is in good agreement with the red shift in the absorption observed upon treatment of 1 with Hg2+. The 1-based test strips were easily fabricated and low-cost, useful in practical and efficient Hg2+ test kits.
2015, 26(10): 1246-1248
doi: 10.1016/j.cclet.2015.05.047
Abstract:
Gasoline evaporation is an important anthropogenic source of atmospheric volatile organic compounds (VOCs). Total OH reactivity for gasoline vapor was measured from 4 kinds of gasoline for the first time by comparative reactivity method (CRM) using proton transfer reaction mass spectrometer (PTR-MS). Compositions of 56 PAMS (photochemical assessment monitoring station) nonmethane hydrocarbons (NMHCs) were measured for both liquid and headspace of gasoline. We found high abundance of alkenes and aromatics in gasoline. The calculated OH reactivity derived from quantified NMHCs speciation accounted for only 57±4% of total reactivity obtained from CRM method. N-Alkenes, only 6 wt% in liquid gasoline, contributed to 70% of calculated reactivity. We assume that the undetected branched alkenes are the possible reason for the missing reactivity. Wesuggest that the priority of gasoline quality improvement is to reduce alkenes content in gasoline in term of reactivity-based control.
Gasoline evaporation is an important anthropogenic source of atmospheric volatile organic compounds (VOCs). Total OH reactivity for gasoline vapor was measured from 4 kinds of gasoline for the first time by comparative reactivity method (CRM) using proton transfer reaction mass spectrometer (PTR-MS). Compositions of 56 PAMS (photochemical assessment monitoring station) nonmethane hydrocarbons (NMHCs) were measured for both liquid and headspace of gasoline. We found high abundance of alkenes and aromatics in gasoline. The calculated OH reactivity derived from quantified NMHCs speciation accounted for only 57±4% of total reactivity obtained from CRM method. N-Alkenes, only 6 wt% in liquid gasoline, contributed to 70% of calculated reactivity. We assume that the undetected branched alkenes are the possible reason for the missing reactivity. Wesuggest that the priority of gasoline quality improvement is to reduce alkenes content in gasoline in term of reactivity-based control.
2015, 26(10): 1249-1254
doi: 10.1016/j.cclet.2015.06.016
Abstract:
The synthesis of three isomers based on Michael addition mechanism for the detection of sulfurcontaining species in aqueous solution is described. These compounds are constructed by conjugating an enone to a coumarin fluorophore. A substituted-phenyl (o, m, or p-) was appended at the carbonyl carbon to adjust the reactivity. The experimental results showed that (E)-7-(diethylamino)-3-(3-(3-hydroxyphenyl)-3-oxoprop-1-en-1-yl)-2H-chromen-2-one (m-QPS) and (E)-7-(diethylamino)-3-(3-(4-hydroxyphenyl)-3-oxoprop-1-en-1-yl)-2H-chromen-2-one (p-QPS) barely react with sulfur-containing nucleophiles, while (E)-7-(diethylamino)-3-(3-(2-hydroxyphenyl)-3-oxoprop-1-en-1-yl)-2H-chromen-2-one (o-QPS) exhibited a fast response toward sulfite, sulfide and thiols in DMSO/phosphate buffer (2:1). The above results are probably due to the intramolecular H-bonding activated Michael addition. More interestingly, cysteine triggered unusual photophysical responses of o-QPS:the original absorption (488 nm) and emission peaks (573 nm) underwent significant blue shifts initially and then recovered, which might be caused by the Michael addition and elimination reaction, respectively.
The synthesis of three isomers based on Michael addition mechanism for the detection of sulfurcontaining species in aqueous solution is described. These compounds are constructed by conjugating an enone to a coumarin fluorophore. A substituted-phenyl (o, m, or p-) was appended at the carbonyl carbon to adjust the reactivity. The experimental results showed that (E)-7-(diethylamino)-3-(3-(3-hydroxyphenyl)-3-oxoprop-1-en-1-yl)-2H-chromen-2-one (m-QPS) and (E)-7-(diethylamino)-3-(3-(4-hydroxyphenyl)-3-oxoprop-1-en-1-yl)-2H-chromen-2-one (p-QPS) barely react with sulfur-containing nucleophiles, while (E)-7-(diethylamino)-3-(3-(2-hydroxyphenyl)-3-oxoprop-1-en-1-yl)-2H-chromen-2-one (o-QPS) exhibited a fast response toward sulfite, sulfide and thiols in DMSO/phosphate buffer (2:1). The above results are probably due to the intramolecular H-bonding activated Michael addition. More interestingly, cysteine triggered unusual photophysical responses of o-QPS:the original absorption (488 nm) and emission peaks (573 nm) underwent significant blue shifts initially and then recovered, which might be caused by the Michael addition and elimination reaction, respectively.
2015, 26(10): 1255-1258
doi: 10.1016/j.cclet.2015.05.046
Abstract:
Dielectric spectra of 4A zeolite particles bulked in deionized water (4A/W) or cyclohexane (4A/C) were measured respectively under different temperatures, and two dielectric relaxations were found in both of 4A/W and 4A/C. Because of existence of water molecules in pores, both low and high frequency relaxation times (τLFR and τHFR) of 4A/Wdecreasedmore sharply than 4A/C with increasing temperature. According to the temperature dependence of τLFR and τHFR, the activation energies of Na+ interacting with framework under hydrated and dehydrated environments were calculated respectively, and the original properties of Na+ in dehydrated zeolite were obtained by analyzing the dielectric properties of 4A/C. Furthermore, a transient state of Na+ motion with temperature was found in 4A/C system.
Dielectric spectra of 4A zeolite particles bulked in deionized water (4A/W) or cyclohexane (4A/C) were measured respectively under different temperatures, and two dielectric relaxations were found in both of 4A/W and 4A/C. Because of existence of water molecules in pores, both low and high frequency relaxation times (τLFR and τHFR) of 4A/Wdecreasedmore sharply than 4A/C with increasing temperature. According to the temperature dependence of τLFR and τHFR, the activation energies of Na+ interacting with framework under hydrated and dehydrated environments were calculated respectively, and the original properties of Na+ in dehydrated zeolite were obtained by analyzing the dielectric properties of 4A/C. Furthermore, a transient state of Na+ motion with temperature was found in 4A/C system.
2015, 26(10): 1259-1264
doi: 10.1016/j.cclet.2015.07.003
Abstract:
As the rate-determining step in native chemical ligation reactions, the thiol-thioester exchange step is important in determining the efficiency of the ligations of peptides. In the present study, systematic theoretical calculations were carried out on the relationships between the structure of different thioesters and the free energy barriers of the thiol-thioester exchange step. According to the calculation results, the thiol-thioester exchange step is disfavored by the steric hindrance around the carbonyl center, while the electronic effect (i.e. conjugation and hyper-conjugation effects) becomes important when the steric hindrance is insignificant.
As the rate-determining step in native chemical ligation reactions, the thiol-thioester exchange step is important in determining the efficiency of the ligations of peptides. In the present study, systematic theoretical calculations were carried out on the relationships between the structure of different thioesters and the free energy barriers of the thiol-thioester exchange step. According to the calculation results, the thiol-thioester exchange step is disfavored by the steric hindrance around the carbonyl center, while the electronic effect (i.e. conjugation and hyper-conjugation effects) becomes important when the steric hindrance is insignificant.
2015, 26(10): 1265-1268
doi: 10.1016/j.cclet.2015.07.001
Abstract:
An iron(III)-catalyzed selective oxidation of 5-HMF to 2, 5-DFF in air at room temperature was developed. This approach gives 2, 5-DFF with good selectivity and yields. Additionally, a two-step process was developed for the oxidation of 2, 5-DFF to 2, 5-FDCA at remarkably high substrate concentrations. This work demonstrates unequivocally the great potential of iron as a cheap and earth-abundant catalyst for the development of new protocols for the conversion of biomass to value-added chemicals.
An iron(III)-catalyzed selective oxidation of 5-HMF to 2, 5-DFF in air at room temperature was developed. This approach gives 2, 5-DFF with good selectivity and yields. Additionally, a two-step process was developed for the oxidation of 2, 5-DFF to 2, 5-FDCA at remarkably high substrate concentrations. This work demonstrates unequivocally the great potential of iron as a cheap and earth-abundant catalyst for the development of new protocols for the conversion of biomass to value-added chemicals.
2015, 26(10): 1269-1272
doi: 10.1016/j.cclet.2015.05.053
Abstract:
Hierarchically mesoporous titanosilicate Ti-SBA-1 was synthesized with organic mesomorphous complexes of polyelectrolyte (poly(acrylic acid) (PAA)) and cationic surfactant (hexadecyl pyridinium chloride (CPC)) as template, tetraethylsiloxane as silica source and titanium ethoxide as titanium source. By adjusting the amount of titanium ethoxide in the synthesis, a series of Ti-SBA-1 particles with different Si/Ti ratio (79-180) were prepared. After incorporation of Ti into the silica framework thewellordered cubic Pm3n mesostructure remained, as well as the morphology, particle size. UV-vis DR spectra of the Ti-SBA-1 materials indicated that incorporated titaniumspecies existed in a highly dispersed state and exhibited tetrahedral and octahedral coordination in the silica framework.
Hierarchically mesoporous titanosilicate Ti-SBA-1 was synthesized with organic mesomorphous complexes of polyelectrolyte (poly(acrylic acid) (PAA)) and cationic surfactant (hexadecyl pyridinium chloride (CPC)) as template, tetraethylsiloxane as silica source and titanium ethoxide as titanium source. By adjusting the amount of titanium ethoxide in the synthesis, a series of Ti-SBA-1 particles with different Si/Ti ratio (79-180) were prepared. After incorporation of Ti into the silica framework thewellordered cubic Pm3n mesostructure remained, as well as the morphology, particle size. UV-vis DR spectra of the Ti-SBA-1 materials indicated that incorporated titaniumspecies existed in a highly dispersed state and exhibited tetrahedral and octahedral coordination in the silica framework.
2015, 26(10): 1273-1277
doi: 10.1016/j.cclet.2015.06.014
Abstract:
A rapid, one-pot and highly efficient protocol for the synthesis of pharmaceutically interesting functionalized 2-amino-3-cyano-4H-pyran and spirooxindole derivatives has been developed using commercially available CsF as a catalyst in the reaction of malononitrile and aryl aldehydes or isatins with 1, 3-cyclohexanediones. The major advantages of this methodology are excellent yield at ambient temperature, very short reaction time (5-10 min), and use of an inexpensive catalyst.
A rapid, one-pot and highly efficient protocol for the synthesis of pharmaceutically interesting functionalized 2-amino-3-cyano-4H-pyran and spirooxindole derivatives has been developed using commercially available CsF as a catalyst in the reaction of malononitrile and aryl aldehydes or isatins with 1, 3-cyclohexanediones. The major advantages of this methodology are excellent yield at ambient temperature, very short reaction time (5-10 min), and use of an inexpensive catalyst.
2015, 26(10): 1278-1282
doi: 10.1016/j.cclet.2015.06.013
Abstract:
Nano titania-supported sulfonic acid (n-TSA) has found to be a highly efficient, eco-friendly and recyclable heterogeneous nanocatalyst for the solvent-free synthesis of 2, 4, 6-triarylpyridines through one-pot three-component reaction of acetophenones, aryl aldehydes and ammonium acetate. This reported method illustrates several advantages such as environmental friendliness reaction conditions, simplicity, short reaction time, easy work up, reusability of catalyst and high yields of the products. One new compound is reported too. Furthermore, the catalyst could be recycled after a simple work-up, and reused at least six times without substantial reduction in its catalytic activity.
Nano titania-supported sulfonic acid (n-TSA) has found to be a highly efficient, eco-friendly and recyclable heterogeneous nanocatalyst for the solvent-free synthesis of 2, 4, 6-triarylpyridines through one-pot three-component reaction of acetophenones, aryl aldehydes and ammonium acetate. This reported method illustrates several advantages such as environmental friendliness reaction conditions, simplicity, short reaction time, easy work up, reusability of catalyst and high yields of the products. One new compound is reported too. Furthermore, the catalyst could be recycled after a simple work-up, and reused at least six times without substantial reduction in its catalytic activity.
2015, 26(10): 1283-1288
doi: 10.1016/j.cclet.2015.05.041
Abstract:
An efficient synthesis of novel 3-(piperidin-4-yl)isoxazolo[4, 5-d]pyrimidine scaffold has been designed and deveopled. A series of 5-phenylurea derivatives was synthesized using this method. Their cytotoxic activities against breast cancer cell line BT-474 were evaluated by CCK-8 assay. Most of them showed potent anti-proliferative activities, of which compound 20 and 21 exhibited IC50s of 1.565 μmol/L and 1.311 μmol/L, respectively. Furthermore, compound 20 and 21 also showed potent inhibitory activities against PI3Kδ with IC50s of 0.286 μmol/L and 0.452 μmol/L, respectively. These results indicate that these 3-(piperidin-4-yl)isoxazolo[4, 5-d] pyrimidine derivatives are novel antitumor agents through the inhibition of PI3Kδ.
An efficient synthesis of novel 3-(piperidin-4-yl)isoxazolo[4, 5-d]pyrimidine scaffold has been designed and deveopled. A series of 5-phenylurea derivatives was synthesized using this method. Their cytotoxic activities against breast cancer cell line BT-474 were evaluated by CCK-8 assay. Most of them showed potent anti-proliferative activities, of which compound 20 and 21 exhibited IC50s of 1.565 μmol/L and 1.311 μmol/L, respectively. Furthermore, compound 20 and 21 also showed potent inhibitory activities against PI3Kδ with IC50s of 0.286 μmol/L and 0.452 μmol/L, respectively. These results indicate that these 3-(piperidin-4-yl)isoxazolo[4, 5-d] pyrimidine derivatives are novel antitumor agents through the inhibition of PI3Kδ.
2015, 26(10): 1289-1292
doi: 10.1016/j.cclet.2015.06.015
Abstract:
A simple and metal-free method has been developed for the construction of quinoline-2, 4-carboxylates under mild conditions via a molecular iodine-catalyzed three-component tandem reaction of arylamines, ethyl glyoxylate, and α-ketoesters. The present protocol provides a convenient and attractive approach to various quinoline-2, 4-carboxylates in moderate to good yields with excellent functional group tolerance.
A simple and metal-free method has been developed for the construction of quinoline-2, 4-carboxylates under mild conditions via a molecular iodine-catalyzed three-component tandem reaction of arylamines, ethyl glyoxylate, and α-ketoesters. The present protocol provides a convenient and attractive approach to various quinoline-2, 4-carboxylates in moderate to good yields with excellent functional group tolerance.
2015, 26(10): 1293-1297
doi: 10.1016/j.cclet.2015.05.051
Abstract:
Rational designing and controlling of nanostructures is a key factor in realizing appropriate properties required for the high-performance energy fields. In the present study, hollow SnO2@C nanoparticles (NPs) with a mean size of 50 nm have been synthesized in large-scale via a facile hydrothermal approach. The morphology and composition of as-obtained products were studied by various characterized techniques. As an anode material for lithium ion batteries (LIBs), the as-prepared hollow SnO2@C NPs exhibit significant improvement in cycle performances. The discharge capacity of lithium battery is as high as 370 mAh g-1, and the current density is 3910 mA g-1(5 C) after 573 cycles. Furthermore, the capacity recovers up to 1100 mAh g-1 at the rate performances in which the current density is recovered to 156.4 mA g-1(0.2 C). Undoubtedly, sub-100 nm SnO2@C NPs provide significant improvement to the electrochemical performance of LIBs as superior-anode nanomaterials, and this carbon coating strategy can pave the way for developing high-performance LIBs.
Rational designing and controlling of nanostructures is a key factor in realizing appropriate properties required for the high-performance energy fields. In the present study, hollow SnO2@C nanoparticles (NPs) with a mean size of 50 nm have been synthesized in large-scale via a facile hydrothermal approach. The morphology and composition of as-obtained products were studied by various characterized techniques. As an anode material for lithium ion batteries (LIBs), the as-prepared hollow SnO2@C NPs exhibit significant improvement in cycle performances. The discharge capacity of lithium battery is as high as 370 mAh g-1, and the current density is 3910 mA g-1(5 C) after 573 cycles. Furthermore, the capacity recovers up to 1100 mAh g-1 at the rate performances in which the current density is recovered to 156.4 mA g-1(0.2 C). Undoubtedly, sub-100 nm SnO2@C NPs provide significant improvement to the electrochemical performance of LIBs as superior-anode nanomaterials, and this carbon coating strategy can pave the way for developing high-performance LIBs.
2015, 26(10): 1298-1302
doi: 10.1016/j.cclet.2015.07.014
Abstract:
Two new triterpenoid saponins, named ginsenoside Rh10 (1) and notoginsenoside ST-6 (2), were isolated from notoginseng medicinal fungal substance. Their structures were elucidated by a combination of 1D and 2D NMR, MS and chemical analysis.
Two new triterpenoid saponins, named ginsenoside Rh10 (1) and notoginsenoside ST-6 (2), were isolated from notoginseng medicinal fungal substance. Their structures were elucidated by a combination of 1D and 2D NMR, MS and chemical analysis.
2015, 26(10): 1303-1306
doi: 10.1016/j.cclet.2015.06.012
Abstract:
A novelmethod for the synthesis of 1, 2, 3, 4-tetraalkyl-1, 4-diarylbutadienes was developed via palladiumcatalyzed cross-coupling of zirconacyclopentadienes with aryl iodides. Equivalent of CuCl was introduced to promote the reaction. The desired products were obtained in good to excellent yields and several of them were reported for the first time.
A novelmethod for the synthesis of 1, 2, 3, 4-tetraalkyl-1, 4-diarylbutadienes was developed via palladiumcatalyzed cross-coupling of zirconacyclopentadienes with aryl iodides. Equivalent of CuCl was introduced to promote the reaction. The desired products were obtained in good to excellent yields and several of them were reported for the first time.
2015, 26(10): 1307-1310
doi: 10.1016/j.cclet.2015.06.017
Abstract:
A series of novel 4-substituted-phenoxy-benzamide derivatives bearing an aryl cycloaliphatic amine moiety were synthesized and evaluated for antiproliferative activity against SW620, HT29 and MGC803 cancer cell lines in vitro. The pharmacological data demonstrated that the majority of target compounds exhibitedmoderate efficacy in HT29 and MGC803 cell lines. Compound 10c showed promising inhibition of hedgehog (Hh) signaling pathway in an Hh-related assay. In addition, the superposition pattern of 10c showed a good fit for a pharmacophoric model generated by Hh inhibitors and provided a basis for further structural optimization.
A series of novel 4-substituted-phenoxy-benzamide derivatives bearing an aryl cycloaliphatic amine moiety were synthesized and evaluated for antiproliferative activity against SW620, HT29 and MGC803 cancer cell lines in vitro. The pharmacological data demonstrated that the majority of target compounds exhibitedmoderate efficacy in HT29 and MGC803 cell lines. Compound 10c showed promising inhibition of hedgehog (Hh) signaling pathway in an Hh-related assay. In addition, the superposition pattern of 10c showed a good fit for a pharmacophoric model generated by Hh inhibitors and provided a basis for further structural optimization.
2015, 26(10): 1311-1314
doi: 10.1016/j.cclet.2015.05.049
Abstract:
Type IV deep eutectic solvent (DES) involves the formation of metal-based eutectics from metal salts or metal salt hydrate incombination with various hydrogen-bonddonors(HBDs) suchas urea, ethylene glycol or acetamide. In current study, twodistinguished approaches were used to synthesize potential DESs, given as the direct heating and the evaporatingmethods. Successful synthesized DESswere subjected forphysical properties characterization by Fourier TransformInfrared (FTIR) Spectroscopy, thermal stability, viscosity, and conductivity analyses. Five novelmanganese (II)-basedDESswere successfully synthesized as reported in this study. Data obtained indicated that the MnCl2·4H2O·acetamide DES exhibits the lowest freezing point (27.5℃), highest thermal stability (193℃ point of dehydration), lowest viscosity (η=112.8 cP) and the highest conductivity (0.12723 mS/cm). The findings obtained reveal the characteristics, nature or features of synthesized DESs as potential industrial solvents.
Type IV deep eutectic solvent (DES) involves the formation of metal-based eutectics from metal salts or metal salt hydrate incombination with various hydrogen-bonddonors(HBDs) suchas urea, ethylene glycol or acetamide. In current study, twodistinguished approaches were used to synthesize potential DESs, given as the direct heating and the evaporatingmethods. Successful synthesized DESswere subjected forphysical properties characterization by Fourier TransformInfrared (FTIR) Spectroscopy, thermal stability, viscosity, and conductivity analyses. Five novelmanganese (II)-basedDESswere successfully synthesized as reported in this study. Data obtained indicated that the MnCl2·4H2O·acetamide DES exhibits the lowest freezing point (27.5℃), highest thermal stability (193℃ point of dehydration), lowest viscosity (η=112.8 cP) and the highest conductivity (0.12723 mS/cm). The findings obtained reveal the characteristics, nature or features of synthesized DESs as potential industrial solvents.
2015, 26(10): 1315-1318
doi: 10.1016/j.cclet.2015.05.040
Abstract:
A series of novel 2-amino-1, 3-thiazole-4-carboxylic acid derivatives were designed and synthesized. Their structures were confirmed by melting points, IR, 1H NMR, 13C NMR, and HRMS or elemental analysis. Biological activities of all title compounds including fungicidal activity and antivirus activity were evaluated systematically. Preliminary bioassays indicated that these compounds exhibited good fungicidal activity at 50 μg/mL, compounds 4b and 4i exhibited over 50% activity against six fungi tested. Most compounds showed good activity against TMV with different models in vivo at 100 μg/mL. Compounds 4c and 4e stood out with high effects against TMV in vivo in all models tested, including protective, inactivative, curative, and inductive activities. These data demonstrate a new strategy for fungi and virus control.
A series of novel 2-amino-1, 3-thiazole-4-carboxylic acid derivatives were designed and synthesized. Their structures were confirmed by melting points, IR, 1H NMR, 13C NMR, and HRMS or elemental analysis. Biological activities of all title compounds including fungicidal activity and antivirus activity were evaluated systematically. Preliminary bioassays indicated that these compounds exhibited good fungicidal activity at 50 μg/mL, compounds 4b and 4i exhibited over 50% activity against six fungi tested. Most compounds showed good activity against TMV with different models in vivo at 100 μg/mL. Compounds 4c and 4e stood out with high effects against TMV in vivo in all models tested, including protective, inactivative, curative, and inductive activities. These data demonstrate a new strategy for fungi and virus control.
2015, 26(10): 1319-1321
doi: 10.1016/j.cclet.2015.05.050
Abstract:
A set of amphiphilic poly(ethylene glycol)-b-poly(ethylene brassylate) (PEG-b-PEB) copolymers based on the PEB hydrophobic block was first synthesized by ring-opening polymerization of ethylene brassylate with an organic catalyst. The EB/PEGmolar ratios and reaction times were adjusted to achieve different chain lengths of PEB. Block copolymers that were characterized by 1H NMR and GPC could selfassemble into multimorphological aggregates in aqueous solution, which were characterized by DLS and TEM. The hydrophobic doxorubicin (DOX) was chosen as a drug model and successfully encapsulated into the nanoparticles. The release kinetics of DOX were investigated.
A set of amphiphilic poly(ethylene glycol)-b-poly(ethylene brassylate) (PEG-b-PEB) copolymers based on the PEB hydrophobic block was first synthesized by ring-opening polymerization of ethylene brassylate with an organic catalyst. The EB/PEGmolar ratios and reaction times were adjusted to achieve different chain lengths of PEB. Block copolymers that were characterized by 1H NMR and GPC could selfassemble into multimorphological aggregates in aqueous solution, which were characterized by DLS and TEM. The hydrophobic doxorubicin (DOX) was chosen as a drug model and successfully encapsulated into the nanoparticles. The release kinetics of DOX were investigated.
2015, 26(10): 1322-1326
doi: 10.1016/j.cclet.2015.05.043
Abstract:
The development of a simple, efficient and sensitive sensor for dissolved oxygen is proposed using a novel type of porous carbon composite membrane/glassy carbon electrode based on the low-cost common filter paper by a simple method. The resulting device exhibited excellent electrocatalytic activities toward the oxygen reduction reaction. Scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical measurements demonstrated that the porous morphology and uniformly dispersed Fe3C nanoparticles of the PCCM play an important role in the oxygen reduction reaction. A linear response range from 2μmol/L up to 110 μmol/L and a detection limit of 1.4 μmol/L was obtained with this sensor. The repeatability of the proposed sensor, evaluated in terms of relative standard deviation, was 3.0%. The successful fabrication of PCCM/GC electrode may promote the development of new porous carbon oxygen reduction reaction material for the oxygen reduction sensor.
The development of a simple, efficient and sensitive sensor for dissolved oxygen is proposed using a novel type of porous carbon composite membrane/glassy carbon electrode based on the low-cost common filter paper by a simple method. The resulting device exhibited excellent electrocatalytic activities toward the oxygen reduction reaction. Scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and electrochemical measurements demonstrated that the porous morphology and uniformly dispersed Fe3C nanoparticles of the PCCM play an important role in the oxygen reduction reaction. A linear response range from 2μmol/L up to 110 μmol/L and a detection limit of 1.4 μmol/L was obtained with this sensor. The repeatability of the proposed sensor, evaluated in terms of relative standard deviation, was 3.0%. The successful fabrication of PCCM/GC electrode may promote the development of new porous carbon oxygen reduction reaction material for the oxygen reduction sensor.
2015, 26(10): 1327-1330
doi: 10.1016/j.cclet.2015.07.020
Abstract:
Based on the lead compound 1 reported in literature, a series of novel BACE1 inhibitors were designed and synthesized, among which compound 11 exhibited a 14-fold improvement in potency over the lead compound 1. This represents a good lead for the discovery of more promising BACE1 inhibitors for the potential treatment of AD.
Based on the lead compound 1 reported in literature, a series of novel BACE1 inhibitors were designed and synthesized, among which compound 11 exhibited a 14-fold improvement in potency over the lead compound 1. This represents a good lead for the discovery of more promising BACE1 inhibitors for the potential treatment of AD.
