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In the present study, the transesterification of glycerol trioleate was carried out over a basic ionic liquid, 1-butyl-3-methylimidazolium hydroxide ([Bmim]OH) and an 87.2% yield of methyl ester was achieved. The product was isolated through simple decantation from the biphasic system due to the immiscibility of [Bmim]OH with ester. [Bmim]OH can be easily recovered and reused six times without dramatic decrease in ester yield.
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A series of novel glyco-gambogic acid (GA) compounds were synthesized and evaluated for their in vitro anti-proliferative activity against human hepatocellular carcinoma (HCC) cells. All compounds showed much better aqueous solubility (0.92 to 1.89 mg/mL) than GA (0.013 mg/mL), and displayed potent inhibition on HCC cells (IC50: 0.21−12.23 μmol/L) and little affects on non-tumor liver cells (IC50: 42.56−86.43 μmol/L), suggesting that glyco-GA compounds selectively inhibit HCC proliferation, and may be promising candidates for further intensive study.
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A combination of HBr and trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane as a new and powerful oxidant was found effective for facile bromination of different aromatic compounds at room temperature in water as a green solvent. Mild reaction conditions, high selectivity and yield, high reaction rate and non-toxicity are some of the major advantages of this synthetic protocol.
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An efficient and simple protocol of copper-catalyzed C-S bond formation between aryl halides and inexpensive and commercially available aminothiourea is reported. A variety of symmetrical diaryl sulfides can be synthesized in good to excellent yields up to 94% with the advantage of avoiding foul-smelling thiols.
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Novel chiral tetraaza ligands (R)-N, N'-bis[2-(piperidin-1-yl)benzylidene]propane-1, 2-diamine 6 and (S)-N-[2-(piperidin-1- yl)benzylidene]-3-{[2-(piperidin-1-yl)benzylidene]amino}-alanine sodium salt 7 have been synthesized and fully characterized by NMR, IR, MS and CD spectra. The catalytic property of the ligands was investigated in Ir-catalyzed enantioselective transfer hydrogenation of ketones. The corresponding optical active alcohols were obtained with high yields and moderate ees under mild reaction conditions.
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An efficient ultrasound-assisted preparation of a series of novel 4-aryl-3-methyl-4,5-dihydro-1H-pyrazolo[3,4-b]pyridin-6(7H)-ones via the reaction of 5-amino-3-methyl-1H-pyrazole, Meldrum's acid and various arylaldehydes using one-pot three-component approach is described. This rapid method produced the products in short reaction times (3–4 min) and excellent yields (87–95%).
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Oleanolic acid 1 exists widely in food, medicinal herbs and other plants and possesses many attractive biological activities. Recently, some oleanolic derivatives were reported to have interesting anti-tumor activities. Herein, using association principle of drug design, OA disaccharide 17 was designed and synthesized by coupling a-L-rhamnopyranosyl-(1→2)-a-L-arabinopyranosyl disaccharide moiety, which has proved to be a unique sugar sequence with strongly antitumor activity, and modified OA with a nitrile at C-17.
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A series of 1-oxacephem analogues were synthesized and their antibacterial properties against five strains of Gram-positive and Gram-negative bacteria were evaluated in vitro while ceftazidine was selected as control. Some of the tested compounds, compound 12c in particular, showed more active against three selected strains than the standard.
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Azidation of aminothiophene derivative 1 afforded the corresponding azido derivative 2. The latter reacted with triphenylphosphine to afford iminophosphorane derivatives 3. Reacting 3 with phenylisocyanate gave the highly reactive carbodiimide intermediate 4, which was reacted with different nitrones to afford new 1,2,4-oxadiazolidin-5-ylidene- aminothiophenes 5a-c. Treatment of 4 with absolute EtOH at room temperature gave methyleneamino-5-(methylthio)thiophene 7, (methylthio)-3-(3-phenylureidothiophene)-2-carboxylate 8 or thienopyrimidine 9 and 10 at refluxing temperature. Finally reaction of carbodiimide intermediate 4 with different secondary amines gave the new thienopyrimidines 11a-c.
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In an attempt to develop potent antitumor agents, new rhodacyanine analogues containing the pyridinium ring (5a–5h), the isoquinolinium ring (6a–6c) and the quinolinium ring (7a–7e) linked to the rhodanine ring via N−N covalent bond were designed, synthesized and evaluated for antitumor activity against human lung cancer cell line (H460) by MTT assay in vitro. Most of the tested compounds showed enhanced antitumor activity with IC50 values ranging from 0.006 to 9.2 μmol/L as compared to the lead compound MKT-077. Among them, the most promising compound 7d (IC50 = 0.006 μmol/L) was 216.7 times more active than MKT-077 (IC50 = 1.3 μmol/L). The preliminary structure-activity relationship of the target compounds was discussed.
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Pentafluorophenylammonium triflate (PFPAT) was found to be a highly efficient catalyst for the preparation of 2,4,6-triarylpyridines from the reaction of acetophenone derivatives, aromatic aldehydes and ammonium acetate. Present methodology offers several advantages, such as short reaction time, high yields, simple procedure with an easy work-up and the absence of any volatile and hazardous organic solvent. In addition, this catalytic system can act as an active, inexpensive, metal-free, recoverable and recyclable catalyst.
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Sulfuric acid-modified polyethylene glycol 6000 (PEG-OSO3H) was applied as an efficient and recyclable catalyst for the synthesis of β-amino carbonyl compounds via the Mannich reaction between aldehydes, aromatic ketones and aromatic amines at room temperature using PEG400-H2O (1:1) as environment-friendly solvents. The reactions were completed in short times and mild reaction conditions with good to excellent yields.
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A new series of N-arylquinoline derivatives 5a-x bearing 2-morpholinoquinoline moiety has been synthesized by one pot base catalyzed cyclocondensation reaction of 2-morpholinoquinoline-3-carbaldehydes 2a-c, malononitrile 3 and β-enaminones 4a-h. All the synthesized compounds were screened for their in vitro antimicrobial activity against six bacterial pathogens, namely S. pneumoniae, C. tetani, B. subtilis, S. typhi, V. cholerae, E. coli and against two fungal pathogens, A. fumigatus and C. albicans using broth microdilution MIC method. Of the compounds studied, Majority of the compounds were found to active against C. tetani, B. subtilis and C. albicans as compared to first-line standard drugs.
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A fast and efficient method is described for the one-pot synthesis of 2,4(1H,3H)-quinazolinediones by cyclization reaction of anthranilic acid derivatives with potassium cyanate and acetic acid in PEG. Good to high yields of the products obtain in short reaction times with simple work-up.
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A simple and practical route is described for the synthesis of 2-ethoxy-(4H)-3,1-benzoxazine-4-ones using the coupling reaction of anthranilic acid derivatives with diethyl dicarbonate following with fast cyclization of the carbamate adduct with a dehydrocyclization agent such as cyanuric chloride and N,N'-dicyclohexylcarbodiimide in PEG at room temperature. High yields of the products obtained under mild reaction conditions with simple work-up of the reaction mixture.
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Three novel redox-active percec-type dendrons were synthesized by mucleophilic substitution reaction of 11-bromoundecyl ferrocene and substituted benzoate. All the resultant ferrocenyl-modified dendrons were confirmed through FT-IR, NMR, and elemental analysis, etc. Furthermore, the thermal properties and electrochemical behavior of these dendrons were monitored with thermogravimetry analysis (TG), differential scanning calorimetry (DSC), polarized optical microscope (POM), and cyclic voltammetry (CV). Abound phase behavior and reversible electrochemical redox reaction process in the DMF solution of these dendrons was observed.
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A series of new biquinoline derivatives containing a thiazole moiety were synthesized by a one-pot, base-catalyzed cyclocondensation reaction of 2-chloro-3-formyl quinoline, malononitrile and enaminone. All the synthesized compounds were characterized by elemental analysis, FT-IR, 1H NMR and 13C NMR data. All the synthesized compounds were screened against three bacterial pathogens, namely B.cereus, B.substilis and E.coli and for antifungal activity against three fungal pathogens, A.niger, F.oxisporum and Rhizopus using the disc diffusion method.
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The synthesis and spectroscopic characterization of ruthenium complexes (R-1 to R-8) of the type [Ru(A)2(B)], (Where A=1,10-phenanthroline/2,2'-bipyridine and B= 3,4,5-tri-OCH3-DPC, 4-CH3-DPC, 4-N-(CH3)2-DPC, 4-NO2-DPC are described. These ligands form bidentate octahedral ruthenium complexes. The title complexes were subjected to in vitro cytotoxic activity measurements against the human cancer T-lymphocyte cell lines MTT assay. In vitro evaluation of these ruthenium complexes revealed cytotoxic activity from 0.24 to 1.4 µg/mL against CEM, 0.44 to 1.9 µg/mL against Molt4/C8, 0.28 to 1.5 µg/mL against L1210, 0.24 to 0.98 µg/mL against HL60, and 0.25 to 1.2 µg/mL against BEL7402, depending the nature of the compound.
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In this paper, polystyrene-based monoliths with highly ordered macroporous structure were synthesized by using SiO2 colloidal crystal as template. SEM observation shows that the macropores are highly ordered and are interconnected by small windows. The BET surface area of PS monolith is about 36.17 m2/g. The polymer monoliths can resist 5MPa pressure, showing high mechanical and compressive strength.
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Polyphenylene sulfides (PPS) and low-melting temperature glasses (LMTG) were used to prepare a PPS/LMTG organic-inorganic hybrid material by melt blending. The etched surfaces of the hybrids were observed by scanning electron microscope (SEM) and the images showed different dispersed phase morphologies compared to traditional filled composites, which maybe induced by shear. Advanced rheometric expanded system (ARES) was used to investigate the rheological behaviors of the hybrids and the results showed that the strain γ dependence of dynamic storage modulus G′ for the hybrids with high contents of LMTG did not appear Payne Effect.
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An ethanol biosensor was fabricated based on a Methylobacterium organophilium-immobilized eggshell membrane and an oxygen (O2) electrode. A linear response for ethanol was obtained in the range of 0.050−7.5 mmol/L with a detection limit of 0.025 mmol/L (S/N = 3) and a R.S.D. of 2.1 %. The response time was less than 100 s at room temperature and ambient pressure. The optimal loading of bacterial cells on the biosensor membrane is 40 mg (wet weight). The optimal working conditions for the microbial biosensor are pH 7.0 phosphate buffer (50 mmol/L) at 20−25 °C. The interference test, operational and storage stability of the biosensor are studied in detail. Finally, the biosensor is applied to determine the ethanol contents in various alcohol samples and the results are comparable to that obtained by gas chromatographic method and the results are satisfactory. Our proposed biosensor provides a convenient, simple and reliable method to determine ethanol content in alcoholic drinks.
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We have investigated the fast ethylamine gas sensing of 2-chloro-3,5-dinitrobenzotrifluoride(CDBF) loaded poly(acrylonitrile)nanofiber based on an intermolecular charge-transfer complexation. Reversible response and recovery were achieved using alternating gas exposure. This system shows a fast ethylamine gas sensing within 0.4 s.
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A new solid-contact Ag+-selective electrode was prepared with 9, 10, 12, 13, 24, 25-hexahydro-5H, 15H, 23H-dibenzo [b, q] [1, 7, 10, 13, 19, 4, 16]-entathiadiazacyclodocosine-6, 16 (7H, 17H)-dione as ionophore, and α, ω-dihexylsexithiophene (DH-6T) ion-to-electron transducer. The sensor exhibited a working concentration range of 10−8 to 10−3 mol/L, with a near-Nernstian slope of 55.1±0.2 mV decade-1 and detection limit of 1.7×10−9 mol/L. The fabricated electrodes demonstrated excellent selectivity over the most common monovalent and divalent cations.
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An efficient and accurate analytical method was developed for the simultaneous determination of 20 synthetic food additives, including three sweeters, seven food colorants, nine synthetic preservatives and caffeine, by high performance liquid chromatography (HPLC) with photodiode array detector (PDA). This method permits the detection of food additives at very low concentrations (0.005~0.150 µg/mL). The applicability was verified by the determination of food additives present in various foodstuffs.
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The graft copolymerization of acrylic acid (AA) onto polyethylene glycol terephthalate (PET) fiber initiated by benzoy peroxide (BPO) was carried out in heterogeneous media. Moreover, modification of the grafted PET fiber (PET-AA) was done by changing the carboxyl group into acylamino and amino groups through the reaction with ethylenediamine. The new modified chelating fiber (NDWJN6) was characterized using elementary analysis, SEM and FT-IR spectroscopy. Adsorption kinetic curve indicated that NDWJN6 could fast remove Pb2+ from water, and adsorption isotherm also indicated that NDWJN6 had high equilibrium adsorption capacity for Pb2+.
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This research presented an annealing strategy to identify hairpin DNA from coil DNA with the same base composition but different arrangements using electrospray mass spectrometry (ESI-MS). A series of single-stranded DNA were annealed with their complementary sequences, respectively. All the five pairs of hairpin DNA and coil DNA were unambiguously distinguished by ESI-MS with annealing strategy. This research offers a potential method to probe the DNA structure by comparing with mass spectral characteristics.
