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2014 Volume 25 Issue 3
2014, 25(3): 389-396
doi: 10.1016/j.cclet.2013.12.014
Abstract:
Well-defined, reversibly light-responsive amphiphilic diblock copolymer grafted with spiropyran, was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. The copolymer self-assembles into polymeric micelles in water and exhibits reversible dissolution and re-aggregation characteristics upon ultraviolet (UV) and visible (Vis)-light irradiation. The fluorescence response of spiropyran immobilized onto the copolymer was light switchable. When nitrobenzoxadiazolyl derivative (NBD) dyes are encapsulated into the core of the micelles, a reversible, light-responsive, dual-color fluorescence resonance energy transfer (FRET) system is constructed and processed, which is well regulated by alternatively UV/vis irradiation. We anticipate these photoswitchable and FRET lighting up nanoparticles will be useful in drug delivery and cell imaging or tracking synchronously.
Well-defined, reversibly light-responsive amphiphilic diblock copolymer grafted with spiropyran, was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. The copolymer self-assembles into polymeric micelles in water and exhibits reversible dissolution and re-aggregation characteristics upon ultraviolet (UV) and visible (Vis)-light irradiation. The fluorescence response of spiropyran immobilized onto the copolymer was light switchable. When nitrobenzoxadiazolyl derivative (NBD) dyes are encapsulated into the core of the micelles, a reversible, light-responsive, dual-color fluorescence resonance energy transfer (FRET) system is constructed and processed, which is well regulated by alternatively UV/vis irradiation. We anticipate these photoswitchable and FRET lighting up nanoparticles will be useful in drug delivery and cell imaging or tracking synchronously.
2014, 25(3): 397-400
doi: 10.1016/j.cclet.2014.01.006
Abstract:
Rhodium-catalyzed cross-coupling reactions of unactivated primary alkyl chlorides with diboron reagents have been developed as practical methods for the synthesis of alkylboronic esters. These reactions expand the concept and utility of Rh(I)-catalyzed cross-coupling of aliphatic electrophiles.
Rhodium-catalyzed cross-coupling reactions of unactivated primary alkyl chlorides with diboron reagents have been developed as practical methods for the synthesis of alkylboronic esters. These reactions expand the concept and utility of Rh(I)-catalyzed cross-coupling of aliphatic electrophiles.
2014, 25(3): 401-405
doi: 10.1016/j.cclet.2013.11.046
Abstract:
CuI nanoparticles as an efficient catalyst have been used for the preparation of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones by the four-component condensation reaction of phthalic anhydride, hydrazine monohydrate, aromatic aldehydes and malononitrile or ethyl cyanoacetate under solventfree conditions in good to excellent yields, short reaction times and environmentally benign, milder reaction conditions.
CuI nanoparticles as an efficient catalyst have been used for the preparation of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones by the four-component condensation reaction of phthalic anhydride, hydrazine monohydrate, aromatic aldehydes and malononitrile or ethyl cyanoacetate under solventfree conditions in good to excellent yields, short reaction times and environmentally benign, milder reaction conditions.
2014, 25(3): 406-410
doi: 10.1016/j.cclet.2013.11.038
Abstract:
Practical BF3·Et2O catalyzed reactions between indoles and a series of carbonyl compounds at room temperature are described, which afford bis(indolyl)methanes with isolated yields up to 96%.
Practical BF3·Et2O catalyzed reactions between indoles and a series of carbonyl compounds at room temperature are described, which afford bis(indolyl)methanes with isolated yields up to 96%.
2014, 25(3): 411-414
doi: 10.1016/j.cclet.2013.12.005
Abstract:
A facile and efficient protocol was developed to access 2-alkoxy-4-amino-N-arylthiazole-5-carboxamides through a three-component one-pot reaction, which involved potassium methyl cyanimidodithiocarbonate, 2-halo-N-arylacetamides and alcohols. The easy availability and the broad structural diversity of substrates make the reaction useful for the construction of libraries in drug discovery.
A facile and efficient protocol was developed to access 2-alkoxy-4-amino-N-arylthiazole-5-carboxamides through a three-component one-pot reaction, which involved potassium methyl cyanimidodithiocarbonate, 2-halo-N-arylacetamides and alcohols. The easy availability and the broad structural diversity of substrates make the reaction useful for the construction of libraries in drug discovery.
2014, 25(3): 415-418
doi: 10.1016/j.cclet.2013.11.014
Abstract:
This study describes a novel application of ion chromatography coupled with post-column photochemically induced fluorimetry derivatisation in alkaline medium and fluorescence detection (IC-hv-FD) for the determination of neonicotinoid pesticide, thiacloprid. In an aqueous medium, this compound showed fluorescence with an excitation maximum at 236 nm and an emission maximum at 353 nm. The 10 mmol/L NaOH with 10% (v/v) acetonitrile solution pumped at flow rate of 1.0 mL/min was used for the chromatographic elution to isocratically separate thiacloprid on an Ion Pac®AS 11 (250 mm×4 mm i.d; 13 mm particle size, Dionex) anion-exchange column. The linear concentration range of application was 0.04-10.0 mg/L, with a relative standard deviation (RSD, n = 7) of 1.7% (for a level of 2.0 mg/L) and detection limit (LOD, S/N = 3) of 9.9 mg/L. The procedure was applied with satisfactory results to the analysis of thiacloprid in ground and lake water samples. Pesticide average spiked recoveries ranged between 95.5% and 114.0%.
This study describes a novel application of ion chromatography coupled with post-column photochemically induced fluorimetry derivatisation in alkaline medium and fluorescence detection (IC-hv-FD) for the determination of neonicotinoid pesticide, thiacloprid. In an aqueous medium, this compound showed fluorescence with an excitation maximum at 236 nm and an emission maximum at 353 nm. The 10 mmol/L NaOH with 10% (v/v) acetonitrile solution pumped at flow rate of 1.0 mL/min was used for the chromatographic elution to isocratically separate thiacloprid on an Ion Pac®AS 11 (250 mm×4 mm i.d; 13 mm particle size, Dionex) anion-exchange column. The linear concentration range of application was 0.04-10.0 mg/L, with a relative standard deviation (RSD, n = 7) of 1.7% (for a level of 2.0 mg/L) and detection limit (LOD, S/N = 3) of 9.9 mg/L. The procedure was applied with satisfactory results to the analysis of thiacloprid in ground and lake water samples. Pesticide average spiked recoveries ranged between 95.5% and 114.0%.
2014, 25(3): 419-422
doi: 10.1016/j.cclet.2013.12.017
Abstract:
An elegant and efficient synthesis of novel 1,2,3-triazole fused 2-aminopyrimidine hybrids has been accomplished for the first time in the green solvent viz. water. The hybrid molecules exhibit significant anti-bacterial activity when screened against three human pathogens viz. Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae. In comparison to the commercially marketed drug tetracycline, some of them are equally potent and a few are more potent.
An elegant and efficient synthesis of novel 1,2,3-triazole fused 2-aminopyrimidine hybrids has been accomplished for the first time in the green solvent viz. water. The hybrid molecules exhibit significant anti-bacterial activity when screened against three human pathogens viz. Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae. In comparison to the commercially marketed drug tetracycline, some of them are equally potent and a few are more potent.
2014, 25(3): 423-426
doi: 10.1016/j.cclet.2013.12.015
Abstract:
An experimental study was carried out on the direct nitration of 1,4,5,8-tetraaza-bicyclo-[4,4,0]-decane to synthesize 1,4,5,8-tetranitro-1,4,5,8-tetraazabicyclo-[4,4,0]-decane (TNAD) with N2O5 catalyzed by acidic ionic liquids. Various ionic liquids, such as [HMim]X, [(CH2)4SO3HMim]X and [Capl]X (X- = pTSO-, NO3-, HSO4-), and various parameters such as equivalents of ionic liquid, molar ratio of N2O5 to the starting material, reaction time and temperature, and solvent were investigated. Ionic liquid [(CH2)4SO3HMim]HSO4 showed better catalytic activity. In the presence of 3% molar ratio of [(CH2)4SO3HMim]HSO4 ionic liquid to the staring material, the yield of 1,4,5,8-tetranitro-1,4,5,8-tetraazabicyclo-[4,4,0]-decane was improved by 6.2% compared to the system without ionic liquid.
An experimental study was carried out on the direct nitration of 1,4,5,8-tetraaza-bicyclo-[4,4,0]-decane to synthesize 1,4,5,8-tetranitro-1,4,5,8-tetraazabicyclo-[4,4,0]-decane (TNAD) with N2O5 catalyzed by acidic ionic liquids. Various ionic liquids, such as [HMim]X, [(CH2)4SO3HMim]X and [Capl]X (X- = pTSO-, NO3-, HSO4-), and various parameters such as equivalents of ionic liquid, molar ratio of N2O5 to the starting material, reaction time and temperature, and solvent were investigated. Ionic liquid [(CH2)4SO3HMim]HSO4 showed better catalytic activity. In the presence of 3% molar ratio of [(CH2)4SO3HMim]HSO4 ionic liquid to the staring material, the yield of 1,4,5,8-tetranitro-1,4,5,8-tetraazabicyclo-[4,4,0]-decane was improved by 6.2% compared to the system without ionic liquid.
2014, 25(3): 427-430
doi: 10.1016/j.cclet.2013.11.029
Abstract:
The triphosphates and homodinucleotides of AZT and d4T have been efficiently synthesized from the corresponding nucleoside 5'-H-phosphonate monoesters via the reactive pyridinium phosphoramidate intermediates.
The triphosphates and homodinucleotides of AZT and d4T have been efficiently synthesized from the corresponding nucleoside 5'-H-phosphonate monoesters via the reactive pyridinium phosphoramidate intermediates.
2014, 25(3): 431-434
doi: 10.1016/j.cclet.2013.12.010
Abstract:
The three-component reaction of 4-hydroxy-1-methyl-2(1H)-quinolinone, aromatic aldehydes and ethyl cyanoacetate was carried out in the presence of a catalytic amount of 4-dimethyl aminopyridine (DMAP) in aqueous ethanol. The reactions result in the formation of pyranoquinoline derivatives in excellent yields. Antibacterial activity has been evaluated against Gram positive and Gram negative bacteria for some of the synthesized compounds. The results indicated that these compounds are moderately effective against bacterial growth and their effectiveness is highest against Pseudomonas aeruginosa.
The three-component reaction of 4-hydroxy-1-methyl-2(1H)-quinolinone, aromatic aldehydes and ethyl cyanoacetate was carried out in the presence of a catalytic amount of 4-dimethyl aminopyridine (DMAP) in aqueous ethanol. The reactions result in the formation of pyranoquinoline derivatives in excellent yields. Antibacterial activity has been evaluated against Gram positive and Gram negative bacteria for some of the synthesized compounds. The results indicated that these compounds are moderately effective against bacterial growth and their effectiveness is highest against Pseudomonas aeruginosa.
2014, 25(3): 435-437
doi: 10.1016/j.cclet.2013.12.009
Abstract:
Bromodimethylsulfonium bromide (BDMS) was used as an efficient brominating reagent for the synthesis of 9,10-dibromoanthracene in dichloromethane. The desired products were obtained in excellent yields.
Bromodimethylsulfonium bromide (BDMS) was used as an efficient brominating reagent for the synthesis of 9,10-dibromoanthracene in dichloromethane. The desired products were obtained in excellent yields.
2014, 25(3): 438-440
doi: 10.1016/j.cclet.2013.12.007
Abstract:
The 2-azido-4-nitroimidazole-based energetic salts were synthesized in a simple and straightforward manner. The structures of these new salts were determined by IR, 1H NMR and 13C NMR spectroscopy and elemental analysis. These salts also exhibited high positive enthalpies of formation, high nitrogen content, and moderate detonation properties.
The 2-azido-4-nitroimidazole-based energetic salts were synthesized in a simple and straightforward manner. The structures of these new salts were determined by IR, 1H NMR and 13C NMR spectroscopy and elemental analysis. These salts also exhibited high positive enthalpies of formation, high nitrogen content, and moderate detonation properties.
2014, 25(3): 441-446
doi: 10.1016/j.cclet.2013.12.002
Abstract:
The titania hollow microspheres with incontinuous multicavities were successfully fabricated via an oil/water (O/W) emulsion process accompanied by sol-gel reaction in the presence of polyvinylpyrrolidone (PVP). In the one-step route, the addition of PVP to the tetrabutyl titanate (TBT) 1-octanol solution as the oil phase of the O/W emulsion clearly expands the size of the cavities inside the microspheres. The npropanol and atoleine alters the polarity of the oil phase to affect the interior structure significantly. The Span 80 is used as a stabilizer to preserve spherical shape. A preliminary mechanism based on phaseseparation for the structural evolution of titania hollow microspheres with multicavities is suggested. Zirconia and alumina hollow microspheres with incontinuous multicavities can also be prepared by this one-step route successfully.
The titania hollow microspheres with incontinuous multicavities were successfully fabricated via an oil/water (O/W) emulsion process accompanied by sol-gel reaction in the presence of polyvinylpyrrolidone (PVP). In the one-step route, the addition of PVP to the tetrabutyl titanate (TBT) 1-octanol solution as the oil phase of the O/W emulsion clearly expands the size of the cavities inside the microspheres. The npropanol and atoleine alters the polarity of the oil phase to affect the interior structure significantly. The Span 80 is used as a stabilizer to preserve spherical shape. A preliminary mechanism based on phaseseparation for the structural evolution of titania hollow microspheres with multicavities is suggested. Zirconia and alumina hollow microspheres with incontinuous multicavities can also be prepared by this one-step route successfully.
2014, 25(3): 447-450
doi: 10.1016/j.cclet.2013.11.048
Abstract:
Methotrexate (MTX) is an antineoplastic therapeutic medicine as antimetabolite of folic acid. In this paper, a sensitive and rapid ultra-performance liquid chromatographic (UPLC) method was developed and validated for the separation and determination of impurities in MTX drug substances. The UPLC method was accomplished on an Agilent Zorbax Extend C-18 (50 mm×4.6 mm, 1.8 mm) with a gradient elution system composed of sodium dihydrogen phosphate in water (20 mmol/L, pH 3.0) and acetonitrile. The flow rate was 2.2 mL/min. The method was validated. The calibration curves displayed good linearity (r > 0.999) within the tested concentration ranges. The limit of detection (LOD) and limit of quantification (LOQ) of the six analytes were all less than 0.774 μg/mL and 1.03 mg/mL. The relative standard deviation (RSD) for intra-and inter-day precision of the six analytes was less than 9.8%, including at the LOQ. The average recovery ranged from 95.2% to 103% except at the LOQ, where recovery ranged from 82.7% to 117%. The validated method was successfully used to determine the relative abundance of six impurities in the MTX drug substances.
Methotrexate (MTX) is an antineoplastic therapeutic medicine as antimetabolite of folic acid. In this paper, a sensitive and rapid ultra-performance liquid chromatographic (UPLC) method was developed and validated for the separation and determination of impurities in MTX drug substances. The UPLC method was accomplished on an Agilent Zorbax Extend C-18 (50 mm×4.6 mm, 1.8 mm) with a gradient elution system composed of sodium dihydrogen phosphate in water (20 mmol/L, pH 3.0) and acetonitrile. The flow rate was 2.2 mL/min. The method was validated. The calibration curves displayed good linearity (r > 0.999) within the tested concentration ranges. The limit of detection (LOD) and limit of quantification (LOQ) of the six analytes were all less than 0.774 μg/mL and 1.03 mg/mL. The relative standard deviation (RSD) for intra-and inter-day precision of the six analytes was less than 9.8%, including at the LOQ. The average recovery ranged from 95.2% to 103% except at the LOQ, where recovery ranged from 82.7% to 117%. The validated method was successfully used to determine the relative abundance of six impurities in the MTX drug substances.
2014, 25(3): 451-454
doi: 10.1016/j.cclet.2013.11.020
Abstract:
The efficient and one-pot synthesis of 4-substituted-1,2,4-triazolidin-3,5-dione derivatives (4-substituted urazoles) via combination of triphosgene, substituted anilines, and ethyl carbazate in the presence of cesium carbonate is presented.
The efficient and one-pot synthesis of 4-substituted-1,2,4-triazolidin-3,5-dione derivatives (4-substituted urazoles) via combination of triphosgene, substituted anilines, and ethyl carbazate in the presence of cesium carbonate is presented.
2014, 25(3): 455-458
doi: 10.1016/j.cclet.2013.12.016
Abstract:
A simple, efficient, and environmentally benign method for the synthesis of 4H-chromene derivatives was developed using well ordered and recoverable amino functionalized silica gel as a base catalyst. The 4H-chromene derivatives were obtained in short time and excellent yield (87%-96%) by three component reaction of aldehydes, malononitrile and cyclic 1,3-diketones in water at 70 ℃.
A simple, efficient, and environmentally benign method for the synthesis of 4H-chromene derivatives was developed using well ordered and recoverable amino functionalized silica gel as a base catalyst. The 4H-chromene derivatives were obtained in short time and excellent yield (87%-96%) by three component reaction of aldehydes, malononitrile and cyclic 1,3-diketones in water at 70 ℃.
2014, 25(3): 459-462
doi: 10.1016/j.cclet.2013.11.049
Abstract:
The oxidation of terminal alkenes was smoothly catalyzed by a recyclable and environmentally friendly catalytic system: [(C18H37)2N(CH3)2]3[PW4O16]/H2O2/formic acid. This new catalytic system is not only capable of catalyzing oxidation of terminal alkenes with a phase-transfer character, but also under solvent-free conditions, avoiding the use of chlorinated solvents. Many different kinds of terminal alkenes could be converted to the corresponding 1,2-diols of high purity in high yields. The catalyst could be easily separated and reused after reaction. Both fresh and used [(C18H37)2N(CH3)2]3[PW4O16] catalyst was characterized by Raman and FTIR.
The oxidation of terminal alkenes was smoothly catalyzed by a recyclable and environmentally friendly catalytic system: [(C18H37)2N(CH3)2]3[PW4O16]/H2O2/formic acid. This new catalytic system is not only capable of catalyzing oxidation of terminal alkenes with a phase-transfer character, but also under solvent-free conditions, avoiding the use of chlorinated solvents. Many different kinds of terminal alkenes could be converted to the corresponding 1,2-diols of high purity in high yields. The catalyst could be easily separated and reused after reaction. Both fresh and used [(C18H37)2N(CH3)2]3[PW4O16] catalyst was characterized by Raman and FTIR.
2014, 25(3): 463-464
doi: 10.1016/j.cclet.2013.11.053
Abstract:
Two new eupodienone lignans, named gymnothelignan T (1) and gymnothelignan U (2) were isolated from the whole plants of endemicmedicinal plant of Gymnotheca chinensis (Saururaceae). The structures of the new compounds were elucidated by means of HRMS, 1D and 2D NMR. Compound 1 was tested for cytotoxic activity in HCT15, HCT116, A549, MCF-7 and HepG2 cells and exhibited no appreciable activity against these tested cell lines with IC50 values above 50 μmol/L.
Two new eupodienone lignans, named gymnothelignan T (1) and gymnothelignan U (2) were isolated from the whole plants of endemicmedicinal plant of Gymnotheca chinensis (Saururaceae). The structures of the new compounds were elucidated by means of HRMS, 1D and 2D NMR. Compound 1 was tested for cytotoxic activity in HCT15, HCT116, A549, MCF-7 and HepG2 cells and exhibited no appreciable activity against these tested cell lines with IC50 values above 50 μmol/L.
2014, 25(3): 465-468
doi: 10.1016/j.cclet.2013.12.001
Abstract:
In the present work, a novel method to extract three kinds of spices, namely vanillin, ethyl vanillin and ethyl maltol from food products such as biscuit, chocolate and milk powder was developed. 1-Octyl-3-methylimidazolium chloride ([Omim]Cl) aqueous solution was selected as the extracting medium. A 0.5 g powder of food product was extracted by 5.0 mL of [Omim]Cl aqueous solution (0.3 mol/L, pH 6.0) under ultrasonication at 50 ℃, and then the extract was centrifuged for 10 min at 4000 rpm. The extract was filtered through a syringe filter and injected into ion chromatography system for analysis. The separation of the three spices was carried out on an anion exchange column. The detection wavelength was set at 280 nm. Compared with traditional extraction solvents, [Omim]Cl aqueous solution displayed particular advantages. The applicability of the proposed method to real sample was confirmed. Under the optimal conditions, good reproducibility of extraction performance was obtained, with the relative standard deviation (RSD) values ranging from 1.9% to 6.3%. The recoveries of spiked samples were between 79.8% and 95.8%. The detection limits (LOD, S/N = 3) of vanillin, ethyl vanillin and ethyl maltol were in the range of 20-45 μg/kg. The use of ionic liquid aqueous solution as extraction solvent was operationally easy and environmental-friendly.
In the present work, a novel method to extract three kinds of spices, namely vanillin, ethyl vanillin and ethyl maltol from food products such as biscuit, chocolate and milk powder was developed. 1-Octyl-3-methylimidazolium chloride ([Omim]Cl) aqueous solution was selected as the extracting medium. A 0.5 g powder of food product was extracted by 5.0 mL of [Omim]Cl aqueous solution (0.3 mol/L, pH 6.0) under ultrasonication at 50 ℃, and then the extract was centrifuged for 10 min at 4000 rpm. The extract was filtered through a syringe filter and injected into ion chromatography system for analysis. The separation of the three spices was carried out on an anion exchange column. The detection wavelength was set at 280 nm. Compared with traditional extraction solvents, [Omim]Cl aqueous solution displayed particular advantages. The applicability of the proposed method to real sample was confirmed. Under the optimal conditions, good reproducibility of extraction performance was obtained, with the relative standard deviation (RSD) values ranging from 1.9% to 6.3%. The recoveries of spiked samples were between 79.8% and 95.8%. The detection limits (LOD, S/N = 3) of vanillin, ethyl vanillin and ethyl maltol were in the range of 20-45 μg/kg. The use of ionic liquid aqueous solution as extraction solvent was operationally easy and environmental-friendly.
2014, 25(3): 469-473
doi: 10.1016/j.cclet.2013.12.022
Abstract:
Silica-bonded N-propyl sulfamic acid (SBNPSA) catalyzed one-pot three component Biginelli condensation of different substituted aromatic aldehydes with ethyl acetoacetate and urea/thoiurea to the respective 3,4-dihydropyrimidin-2-(1H)-ones and thiones in environment friendly procedure is described. The facile reaction conditions, simple isolation and purification procedures of this method make it a good option for the synthesis of dihydropyrimidinones.
Silica-bonded N-propyl sulfamic acid (SBNPSA) catalyzed one-pot three component Biginelli condensation of different substituted aromatic aldehydes with ethyl acetoacetate and urea/thoiurea to the respective 3,4-dihydropyrimidin-2-(1H)-ones and thiones in environment friendly procedure is described. The facile reaction conditions, simple isolation and purification procedures of this method make it a good option for the synthesis of dihydropyrimidinones.
2014, 25(3): 474-478
doi: 10.1016/j.cclet.2013.11.039
Abstract:
Novel histone deacetylase (HDAC) inhibitors 9a-1 were designed and synthesized by coupling the carboxyl group of salicylic acid (SA) with N-hydroxycinnamamides through various alkylol amines, and their in vitro biological activities were evaluated. The N-hydroxycinnamamide/SA hybrids 9b-f and 9h showed good to moderate anti-tumor activities. Notably, compound 9e had a greater potency, comparable to vorinostat (SAHA), in human colon carcinoma cells, which was probably, or at least partially, attributable to the positive effects of the chain length noted in alkylol amines. Furthermore, the HDAC inhibitory activities of 9e against Hela cell nuclear were also similar to that of vorinostat (SAHA), while the tested compounds 9c-f did not exhibit any isoform selectivity in the inhibition of HDACs. In addition, compound 9e could selectively inhibit tumor cells, but not inhibit non-tumor cell proliferation in vitro. Our findings suggest that the N-hydroxycinnamamide/SA hybrids may hold significant promise as therapeutic agents for the intervention of human cancers.
Novel histone deacetylase (HDAC) inhibitors 9a-1 were designed and synthesized by coupling the carboxyl group of salicylic acid (SA) with N-hydroxycinnamamides through various alkylol amines, and their in vitro biological activities were evaluated. The N-hydroxycinnamamide/SA hybrids 9b-f and 9h showed good to moderate anti-tumor activities. Notably, compound 9e had a greater potency, comparable to vorinostat (SAHA), in human colon carcinoma cells, which was probably, or at least partially, attributable to the positive effects of the chain length noted in alkylol amines. Furthermore, the HDAC inhibitory activities of 9e against Hela cell nuclear were also similar to that of vorinostat (SAHA), while the tested compounds 9c-f did not exhibit any isoform selectivity in the inhibition of HDACs. In addition, compound 9e could selectively inhibit tumor cells, but not inhibit non-tumor cell proliferation in vitro. Our findings suggest that the N-hydroxycinnamamide/SA hybrids may hold significant promise as therapeutic agents for the intervention of human cancers.
2014, 25(3): 479-481
doi: 10.1016/j.cclet.2013.12.006
Abstract:
An improved and efficient method for synthesis of (lS,4S)-2-oxa-5-azabicyclo[2.2.1]heptane (1) from trans-4-hydroxy-L-proline was developed. Using benzyloxycarbonyl (Cbz) as protection group of amine, the reactions were inmild conditions, and the title compound 1 was accomplished in six steps in overall yield of 70%.
An improved and efficient method for synthesis of (lS,4S)-2-oxa-5-azabicyclo[2.2.1]heptane (1) from trans-4-hydroxy-L-proline was developed. Using benzyloxycarbonyl (Cbz) as protection group of amine, the reactions were inmild conditions, and the title compound 1 was accomplished in six steps in overall yield of 70%.
2014, 25(3): 482-484
doi: 10.1016/j.cclet.2013.12.013
Abstract:
An isothermal graphene oxide (GO)-based SYBR Green I fluorescence platform for sensitive detection of RNA transcription levels is proposed. Briefly, a synthesized T7 DNA template was transcribed by T7 RNA polymerase, to producemany copies of single-stranded (ss) RNA transcripts. The ssRNA transcripts were then hybridized with a label-free ssDNA probe which alone will be adsorbed on the GO surface. The resultant double-stranded (ds) RNA:DNA hybrids were incubated with GO and SYBR Green I. Then the hybrid binding with SYBR Green I emits enhanced fluorescence for detection. Experimental results show that the detection limit of the method is 0.5 pmol/L of T7 DNA template. A calibration curve with a linearity range of 0.5 pmol/L to 5 nmol/L is established, thus, making quantitative analysis feasible. The method may become a powerful tool for RNA transcription detection due to its sensitivity, rapidity and convenience.
An isothermal graphene oxide (GO)-based SYBR Green I fluorescence platform for sensitive detection of RNA transcription levels is proposed. Briefly, a synthesized T7 DNA template was transcribed by T7 RNA polymerase, to producemany copies of single-stranded (ss) RNA transcripts. The ssRNA transcripts were then hybridized with a label-free ssDNA probe which alone will be adsorbed on the GO surface. The resultant double-stranded (ds) RNA:DNA hybrids were incubated with GO and SYBR Green I. Then the hybrid binding with SYBR Green I emits enhanced fluorescence for detection. Experimental results show that the detection limit of the method is 0.5 pmol/L of T7 DNA template. A calibration curve with a linearity range of 0.5 pmol/L to 5 nmol/L is established, thus, making quantitative analysis feasible. The method may become a powerful tool for RNA transcription detection due to its sensitivity, rapidity and convenience.
