Login In
2016 Volume 27 Issue 10
2016, 27(10): 1577-1581
doi: 10.1016/j.cclet.2016.06.040
Abstract:
Gastrolatathioneine (1), an unusual natural product derived from ergothioneine, a fungal amino acid containing an imidazole-2-thione moiety, was isolated from an aqueous extract of "tian ma" (the Gastrodia elata rhizomes). The structure of 1 including the absolute configuration was determined by extensive spectroscopic data analysis, combined with comparison of an experimental circular dichroism spectrum and calculated electronic circular dichroism spectra of stereoisomers, and confirmed by X-ray crystallography. The natural origin of 1 was proved by HPLC-ESIMS analysis of the crude extract. A biogenetic pathway of 1 is proposed on the basis of metabolic post-modification of ergothioneine that is biosynthesized by a symbiotic fungus. The plant and symbiotic fungus are co-producers of 1.
Gastrolatathioneine (1), an unusual natural product derived from ergothioneine, a fungal amino acid containing an imidazole-2-thione moiety, was isolated from an aqueous extract of "tian ma" (the Gastrodia elata rhizomes). The structure of 1 including the absolute configuration was determined by extensive spectroscopic data analysis, combined with comparison of an experimental circular dichroism spectrum and calculated electronic circular dichroism spectra of stereoisomers, and confirmed by X-ray crystallography. The natural origin of 1 was proved by HPLC-ESIMS analysis of the crude extract. A biogenetic pathway of 1 is proposed on the basis of metabolic post-modification of ergothioneine that is biosynthesized by a symbiotic fungus. The plant and symbiotic fungus are co-producers of 1.
2016, 27(10): 1582-1585
doi: 10.1016/j.cclet.2016.04.004
Abstract:
Two new iridium complexes, (dfppy)2Ir(L-alanine) (dfppy=2-(2, 4-difluorophenyl)pyridine) and (piq)2Ir(L-alanine) (piq=L-phenylisoquinoline) were prepared with L-alanine as ancillary ligand. The two complexes show bright greenish-blue and red emission respectively. Theoretic study demonstrated that the emission nature of these complexes is mainly determined by the main ligand. And their improved aqueous solubility and the retained quantum yield favor their application in cell imaging. Intracellular imaging suggested that these two complexes have fine cell membrane permeability and is mainly distributed in cytoplasm. This study displayed a new strategy to design aqueous soluble phosphorescent cyclometallated Ir(Ⅲ) complex via introducing amino acid as ancillary ligand.
Two new iridium complexes, (dfppy)2Ir(L-alanine) (dfppy=2-(2, 4-difluorophenyl)pyridine) and (piq)2Ir(L-alanine) (piq=L-phenylisoquinoline) were prepared with L-alanine as ancillary ligand. The two complexes show bright greenish-blue and red emission respectively. Theoretic study demonstrated that the emission nature of these complexes is mainly determined by the main ligand. And their improved aqueous solubility and the retained quantum yield favor their application in cell imaging. Intracellular imaging suggested that these two complexes have fine cell membrane permeability and is mainly distributed in cytoplasm. This study displayed a new strategy to design aqueous soluble phosphorescent cyclometallated Ir(Ⅲ) complex via introducing amino acid as ancillary ligand.
2016, 27(10): 1586-1591
doi: 10.1016/j.cclet.2016.04.012
Abstract:
MXenes, serving as a novel family of two-dimensional (2D) metal carbides, have attracted great research interest as one of the promising electrode materials due to the unique properties. However, to our best knowledge, the 2D titanium carbide (one kind of MXene) used in constructing microsupercapacitors (MSCs) has not yet been reported to date. To this end, we firstly produce the MXene films on various kinds of substrates including polyethylene terephthalate (PET), silicon oxide film and titanium plate through vacuum-filtrating and subsequent controlled transferring. On this basis, flexible all-solid-state symmetric MSCs on PET substrate based on MXene films are fabricated by micro-fabrication process using polyvinyl alcohol (PVA)/H2SO4 as gel electrolyte. The results show that the as-made MSC has an ultrahigh rate performance with the scan rate of up to 1000 V s-1 as well as an ultrafast frequency response (τ0=0.5 ms). In addition, the MSC delivers a large volumetric capacitance of 1.44 F cm-3, a high volumetric energy density (0.2 mWh cm-3) at the current density of 0.288 A cm-3 and a good cycling stability. Our research results presented here may pave the way for a new potential application of MXene in micro-power suppliers and micro-energy storage devices.
MXenes, serving as a novel family of two-dimensional (2D) metal carbides, have attracted great research interest as one of the promising electrode materials due to the unique properties. However, to our best knowledge, the 2D titanium carbide (one kind of MXene) used in constructing microsupercapacitors (MSCs) has not yet been reported to date. To this end, we firstly produce the MXene films on various kinds of substrates including polyethylene terephthalate (PET), silicon oxide film and titanium plate through vacuum-filtrating and subsequent controlled transferring. On this basis, flexible all-solid-state symmetric MSCs on PET substrate based on MXene films are fabricated by micro-fabrication process using polyvinyl alcohol (PVA)/H2SO4 as gel electrolyte. The results show that the as-made MSC has an ultrahigh rate performance with the scan rate of up to 1000 V s-1 as well as an ultrafast frequency response (τ0=0.5 ms). In addition, the MSC delivers a large volumetric capacitance of 1.44 F cm-3, a high volumetric energy density (0.2 mWh cm-3) at the current density of 0.288 A cm-3 and a good cycling stability. Our research results presented here may pave the way for a new potential application of MXene in micro-power suppliers and micro-energy storage devices.
2016, 27(10): 1592-1596
doi: 10.1016/j.cclet.2016.04.020
Abstract:
Two novel π-conjugated cyanostilbene derivatives, FLU-CNPH and TPE-CNPH, were designed and synthesized by introducing the strong electron donor 1, 4-dihydropyrro[3 , 2-b ]indole and AIE electron donor tetraphenylethylene (TPE) to the (30,50-bis(trifluoromethyl)-biphenyl-4-yl)-acetonitrile, respectively. Both of them were fully characterized and their AIE behaviors were investigated using fluorescence spectroscopy and FE-SEM images. Their optimized structures and frontier molecular orbitals were calculated with the DFT by using Materials Studio 7.0 software to study the relationship between the structure and properties.
Two novel π-conjugated cyanostilbene derivatives, FLU-CNPH and TPE-CNPH, were designed and synthesized by introducing the strong electron donor 1, 4-dihydropyrro[
2016, 27(10): 1597-1601
doi: 10.1016/j.cclet.2016.03.008
Abstract:
Urinary albumin is an important diagnostic and prognostic marker for cardiorenal disease. Recent studies have shown that elevation of albumin excretion even in normal concentration range is associated with increased cardiorenal risk. Therefore, accurate measurement of urinary albumin in normal concentration range is necessary for clinical diagnosis. In this work, thiourea-functionalized silica nanoparticles are prepared and used for preconcentration of albumin in urine. The adsorbent with the analyte was then used for near-infrared diffuse reflectance spectroscopy measurement directly and partial least squares model was established for quantitative prediction. Forty samples were taken as calibration set for establishing PLS model and 17 samples were used for validation of the method. The correlation coefficient and the root mean squared error of cross validation is 0.9986 and 0.43, respectively. Residual predictive deviation value of the model is as high as 18.8. The recoveries of the 17 validation samples in the concentration range of 3.39-24.39 mg/L are between 95.9%-113.1%. Therefore, the method may provide a candidate method to quantify albumin excretion in urine.
Urinary albumin is an important diagnostic and prognostic marker for cardiorenal disease. Recent studies have shown that elevation of albumin excretion even in normal concentration range is associated with increased cardiorenal risk. Therefore, accurate measurement of urinary albumin in normal concentration range is necessary for clinical diagnosis. In this work, thiourea-functionalized silica nanoparticles are prepared and used for preconcentration of albumin in urine. The adsorbent with the analyte was then used for near-infrared diffuse reflectance spectroscopy measurement directly and partial least squares model was established for quantitative prediction. Forty samples were taken as calibration set for establishing PLS model and 17 samples were used for validation of the method. The correlation coefficient and the root mean squared error of cross validation is 0.9986 and 0.43, respectively. Residual predictive deviation value of the model is as high as 18.8. The recoveries of the 17 validation samples in the concentration range of 3.39-24.39 mg/L are between 95.9%-113.1%. Therefore, the method may provide a candidate method to quantify albumin excretion in urine.
2016, 27(10): 1602-1606
doi: 10.1016/j.cclet.2016.03.031
Abstract:
Luminescent silica nanocomposites functionalized with a Eu-complex have been prepared and characterized.The europium complex is composed of 2,2'-bipyridyl (BPy) and 2-(4-bromomethyl)-phenylpropionic acid (BMPPA),which contains highly active benzyl bromide substituents and can covalently bind with poly (4-vinylpyridine)(P4VP)-modified silica nanoparticles (nanoSiO2P4VP) to form nanoSiO2P4VPEuBPy composites.Microscopic images revealed that the nanoSiO2P4VPEuBPy composites easily formed aggregates,due to an inter-particle binding caused by the benzyl bromide among the composites.The as-prepared nanocomposites showed the typical emissions of Eu (III) ions at the wavelengths from 580 nm to 750 nm designated to the 5D0→7Fn transitions.Time-resolved fluorescence decay measurements revealed that the emission lifetime was approximately 0.204 ms and 0.576 ms for the nanoSiO2EuBPy composites,a little shorter than that in the Eu (BMPPA)3BPy complex.
Luminescent silica nanocomposites functionalized with a Eu-complex have been prepared and characterized.The europium complex is composed of 2,2'-bipyridyl (BPy) and 2-(4-bromomethyl)-phenylpropionic acid (BMPPA),which contains highly active benzyl bromide substituents and can covalently bind with poly (4-vinylpyridine)(P4VP)-modified silica nanoparticles (nanoSiO2P4VP) to form nanoSiO2P4VPEuBPy composites.Microscopic images revealed that the nanoSiO2P4VPEuBPy composites easily formed aggregates,due to an inter-particle binding caused by the benzyl bromide among the composites.The as-prepared nanocomposites showed the typical emissions of Eu (III) ions at the wavelengths from 580 nm to 750 nm designated to the 5D0→7Fn transitions.Time-resolved fluorescence decay measurements revealed that the emission lifetime was approximately 0.204 ms and 0.576 ms for the nanoSiO2EuBPy composites,a little shorter than that in the Eu (BMPPA)3BPy complex.
2016, 27(10): 1607-1611
doi: 10.1016/j.cclet.2016.03.037
Abstract:
Pyrolysis experiments were carried out in a tubular furnace. The characteristics of pyrolysis tar were analyzed by GC/MS. The results indicated that the aliphatic hydrocarbon yield derived from co-pyrolysis tar of cotton stalk and Shenmu coal was obviously higher than that of Shenmu coal pyrolysis under optimum condition. Moreover, microcrystalline cellulose was selected as a model compound and the copyrolysis tar of microcrystalline cellulose and Shenmu coal was analyzed for comparison. Base on the experimental results, it was indicated that the alkyl radicals generated from pyrolysis were converted to aliphatic hydrocarbons by radical reactions. Furthermore, the mechanisms of aliphatic hydrocarbon formation were discussed during co-pyrolysis of cotton stalk and Shenmu coal.
Pyrolysis experiments were carried out in a tubular furnace. The characteristics of pyrolysis tar were analyzed by GC/MS. The results indicated that the aliphatic hydrocarbon yield derived from co-pyrolysis tar of cotton stalk and Shenmu coal was obviously higher than that of Shenmu coal pyrolysis under optimum condition. Moreover, microcrystalline cellulose was selected as a model compound and the copyrolysis tar of microcrystalline cellulose and Shenmu coal was analyzed for comparison. Base on the experimental results, it was indicated that the alkyl radicals generated from pyrolysis were converted to aliphatic hydrocarbons by radical reactions. Furthermore, the mechanisms of aliphatic hydrocarbon formation were discussed during co-pyrolysis of cotton stalk and Shenmu coal.
2016, 27(10): 1612-1616
doi: 10.1016/j.cclet.2016.03.043
Abstract:
Four new sesquiterpenoids, 4,8-dioxo-6β-hydroxyl-7β,11-epoxycarabrane (1), 4,8-dioxo-6β-hydroxyl-7α,11-epoxycarabrane (2), wenyujinins Q and R (3-4), and nine known sesquiterpenoids (5-13) were isolated from the Curcuma wenyujin (C. wenyujin) dreg. Their structures and relative configurations were elucidated using 1D, 2D NMR, and HR-ESI-MS data. All the compounds were isolated for the first time from the C. wenyujin dreg and evaluated for their antibacterial and antifungal activities. Compounds 3, 5-8 exhibited strong broad-spectrum antifungal activities against tested nine pathogenic fungi.
Four new sesquiterpenoids, 4,8-dioxo-6β-hydroxyl-7β,11-epoxycarabrane (1), 4,8-dioxo-6β-hydroxyl-7α,11-epoxycarabrane (2), wenyujinins Q and R (3-4), and nine known sesquiterpenoids (5-13) were isolated from the Curcuma wenyujin (C. wenyujin) dreg. Their structures and relative configurations were elucidated using 1D, 2D NMR, and HR-ESI-MS data. All the compounds were isolated for the first time from the C. wenyujin dreg and evaluated for their antibacterial and antifungal activities. Compounds 3, 5-8 exhibited strong broad-spectrum antifungal activities against tested nine pathogenic fungi.
2016, 27(10): 1617-1621
doi: 10.1016/j.cclet.2016.04.007
Abstract:
A palladium-catalyzed multi-acetoxylation of 1,3-disubstituted 1H-pyrazole-5-carboxylate derivatives containing multiple potential reactive sites is described. Therein, the sequence of this process has been appropriately investigated. The protocol mainly provides the di- and tri-acetoxylated products for 1,3-diarylpyrazoles. Besides, it is found that the acetoxylation of C(sp3)-H bond is prior to that of C(sp2)-H bond under structurally competitive conditions.
A palladium-catalyzed multi-acetoxylation of 1,3-disubstituted 1H-pyrazole-5-carboxylate derivatives containing multiple potential reactive sites is described. Therein, the sequence of this process has been appropriately investigated. The protocol mainly provides the di- and tri-acetoxylated products for 1,3-diarylpyrazoles. Besides, it is found that the acetoxylation of C(sp3)-H bond is prior to that of C(sp2)-H bond under structurally competitive conditions.
2016, 27(10): 1622-1625
doi: 10.1016/j.cclet.2016.04.009
Abstract:
A concise and efficient approach was developed for the synthesis of pentacyclic compounds containing coumarin, pyrrole, indene in a regioselective manner in good yields via the reactions of N-substituted 4-aminocoumarin compounds and ninhydrin using microwave irradiation. No catalysts are required in our protocol.
A concise and efficient approach was developed for the synthesis of pentacyclic compounds containing coumarin, pyrrole, indene in a regioselective manner in good yields via the reactions of N-substituted 4-aminocoumarin compounds and ninhydrin using microwave irradiation. No catalysts are required in our protocol.
Design and synthesis of 5-cyclopropyl substituted cyclic acylguanidine compounds as BACE1 inhibitors
2016, 27(10): 1626-1629
doi: 10.1016/j.cclet.2016.05.002
Abstract:
By taking compound 1 as a lead, a series of 5-cyclopropyl substituted cyclic acylguanidine compounds were designed and synthesized as BACE1 inhibitors, compound 4d exhibited 84-fold improved inhibition efficiency than lead compound 1. The diphenyl fragment at the P3 position and the substituents at the second phenyl ring were essential for the compounds to achieve improved inhibition efficiency. This SAR studies provides new insights into the design and synthesis of more promising BACE1 inhibitors for the potential treatment of AD.
By taking compound 1 as a lead, a series of 5-cyclopropyl substituted cyclic acylguanidine compounds were designed and synthesized as BACE1 inhibitors, compound 4d exhibited 84-fold improved inhibition efficiency than lead compound 1. The diphenyl fragment at the P3 position and the substituents at the second phenyl ring were essential for the compounds to achieve improved inhibition efficiency. This SAR studies provides new insights into the design and synthesis of more promising BACE1 inhibitors for the potential treatment of AD.
2016, 27(10): 1630-1634
doi: 10.1016/j.cclet.2016.06.034
Abstract:
Small molecule sodium ion channel blockers with a pharmacophore of α-aminoamide have exhibited anti-allodynia effects on neuropathic pain. A library of new α-aminoamide derivatives containing a scaffold of substituted benzene were designed and synthesized. These compounds were evaluated in mice formalin model and they exhibited significant analgesic activities. However, the anti-allodynia mechanism of these compounds remains unclear; some of the target compounds can only moderately inhibit the sodium ion channel, Nav1.7, in a whole-cell patch clamp assay. These results suggest that introduction of the moiety of substituted benzene to α-aminoamide derivatives can improve their bioactivity and further study is warranted.
Small molecule sodium ion channel blockers with a pharmacophore of α-aminoamide have exhibited anti-allodynia effects on neuropathic pain. A library of new α-aminoamide derivatives containing a scaffold of substituted benzene were designed and synthesized. These compounds were evaluated in mice formalin model and they exhibited significant analgesic activities. However, the anti-allodynia mechanism of these compounds remains unclear; some of the target compounds can only moderately inhibit the sodium ion channel, Nav1.7, in a whole-cell patch clamp assay. These results suggest that introduction of the moiety of substituted benzene to α-aminoamide derivatives can improve their bioactivity and further study is warranted.
2016, 27(10): 1635-1640
doi: 10.1016/j.cclet.2016.05.008
Abstract:
A simple layer-by-layer deposition technique was used to fabricate the multilayer thin films of unmodified silver triangular nanoplates (AgTNPs). The multilayer of AgTNPs thin films were fabricated by alternate deposition of each anionic sodium citrate stabilized AgTNPs and cationic poly(diallyldimethylammonium chloride). All prepared AgTNPs multilayer thin films were exhibited a strong plasmon band at the wavelength of 667 nm, which confirmed the formation of AgTNPs onto the substrate. The characteristics of the multilayer thin films were investigated using contact angle measurement, UV-visible spectroscopy, X-ray diffraction analysis (XRD), atomic force microscope (AFM) and field emission scanning electron microscope (FESEM). As these films are to be used as a mercury (II) colorimetric sensor, the changes in optical properties of the films were evaluated for various mercury (II) concentrations. AgTNPs assembled into thin films showed a strong color shift from blue to mauve and colorless when exposed to mercury (II). The constructed multilayer thin films exhibited excellent color changes of mercury (II) with a linear range between 0.5 and 20 ppm. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.45 0.002 and 1.52 0.002 ppm, respectively. The recovery values of AgTNPs multilayer thin films are satisfactory in the range of 100.1%-106.4% when applied to determining mercury (II) in water samples.
A simple layer-by-layer deposition technique was used to fabricate the multilayer thin films of unmodified silver triangular nanoplates (AgTNPs). The multilayer of AgTNPs thin films were fabricated by alternate deposition of each anionic sodium citrate stabilized AgTNPs and cationic poly(diallyldimethylammonium chloride). All prepared AgTNPs multilayer thin films were exhibited a strong plasmon band at the wavelength of 667 nm, which confirmed the formation of AgTNPs onto the substrate. The characteristics of the multilayer thin films were investigated using contact angle measurement, UV-visible spectroscopy, X-ray diffraction analysis (XRD), atomic force microscope (AFM) and field emission scanning electron microscope (FESEM). As these films are to be used as a mercury (II) colorimetric sensor, the changes in optical properties of the films were evaluated for various mercury (II) concentrations. AgTNPs assembled into thin films showed a strong color shift from blue to mauve and colorless when exposed to mercury (II). The constructed multilayer thin films exhibited excellent color changes of mercury (II) with a linear range between 0.5 and 20 ppm. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.45 0.002 and 1.52 0.002 ppm, respectively. The recovery values of AgTNPs multilayer thin films are satisfactory in the range of 100.1%-106.4% when applied to determining mercury (II) in water samples.
2016, 27(10): 1641-1643
doi: 10.1016/j.cclet.2016.03.020
Abstract:
Inhibitor hydroquinone (HQ) was added to the reaction system to prepare polypropylene/polystyrene (PP/PS) blend pellets without PS on the surface during diffusion and subsequent polymerization of styrene in isotactic polypropylene pellets. The effects of the amount of HQ on diametrical distribution of PS, surface morphology of the pellets and phase morphology inside the blend pellets were investigated.
Inhibitor hydroquinone (HQ) was added to the reaction system to prepare polypropylene/polystyrene (PP/PS) blend pellets without PS on the surface during diffusion and subsequent polymerization of styrene in isotactic polypropylene pellets. The effects of the amount of HQ on diametrical distribution of PS, surface morphology of the pellets and phase morphology inside the blend pellets were investigated.
2016, 27(10): 1644-1648
doi: 10.1016/j.cclet.2016.03.040
Abstract:
In this study, etherification of ginkgolide B and dimethylaminoethyl chloride hydrochloride was investigated as a model reaction in a micro-flow system (MFS), providing the resulting ethers in high yield with fewer side effects. Meanwhile, this novel process in MFS worked well for other ginkgolides from Ginkgol biloba and halides, giving moderate yields.
In this study, etherification of ginkgolide B and dimethylaminoethyl chloride hydrochloride was investigated as a model reaction in a micro-flow system (MFS), providing the resulting ethers in high yield with fewer side effects. Meanwhile, this novel process in MFS worked well for other ginkgolides from Ginkgol biloba and halides, giving moderate yields.
