摘要 (
)
可视化
收藏
TMSOTf-catalyzed intramolecular seleno-arylation of tethered alkenes was performed using polystyrene-supported succinimidyl selenide as the selenium source. This catalytic process provides an efficient method for the regioselective synthesis of dihydrocoumarins possessing a seleno-functionality, followed by traceless cleavage of selenium linker to provide dihydrocoumarins and coumarins in good yields and purities.
摘要 (
)
可视化
收藏
Asymmetric reduction of α-hydroxy aromatic ketones was carried out by using carrot enzymes system, yielding corresponding chiral vicinal diols with special functional groups. The optimum reaction conditions were obtained after investigation of various influencing factors. Chiral aryl vicinal diols were produced with good yields and excellent enantiomeric excesses under appropriate conditions. Meanwhile, the steric factors and electronic effects of the substituents on the aromatic ring were shown to have an interesting influence on both yield and enantioselectivity.
摘要 (
)
可视化
收藏
An effective method for the synthesis of vinyl thioethers through the conjugate addition of ethanethiol to electron-deficient alkynes promoted by BF3.Et2O has been developed. Electron-deficient internal alkynes react with ethanethiol in this system to yield mainly Z-isomer of vinyl thioether adducts, while electron-deficient terminal alkynes afford mainly E-isomer of vinyl thioether adducts.
摘要 (
)
可视化
收藏
Four bis(disiloxanyl)-m-carboranes ((RSiMe2OSiMe2)2-m-C2B10H10, R=H, vinyl, ethynyl, allyl) were synthesized from the reaction of bis(hydroxydimethylsilyl)-m-carborane and disilazanes, and characterized by infrared spectra (IR), nuclear magnetic resonance (NMR) and mass spectrometry (MS).
摘要 (
)
可视化
收藏
A series of novel quaternary ammonium surfactants containing adamantane were designed and synthesized from 1-adamantanecarboxylic acid. The structures of target surfactants were confirmed by 1H NMR, elements analysis and FTIR. Surface properties of these surfactants were investigated. Due to the lipophilicity of adamantane, the CMC and C20 values of the synthesized quaternary ammonium surfactants are lower than that of conventional quaternary ammonium surfactants.
摘要 (
)
可视化
收藏
Ring opening of aziridine with dialkyl amine took place readily in the presence of catalytic amounts of tri-n-butylphosphane (10 mol%) in the mixture of CH3CN / H2O (10:1), giving corresponding vicinal diamines in mediate to high yields (58~95 %) with good regioselectivitie, while aromatic secondary amine could not react under the same conditions. Tri-n-butylphosphane exhibited different catalytic selectivity to amines from Lewis acid catalysts.
摘要 (
)
可视化
收藏
A facile and improved route for the synthesis of the orally active spiroindoline-based growth hormone secretagogue, MK-677 was described. The key step adopted the Fischer indole/reduction strategy. The preparation of the key intermediates N-protected piperidine carboxaldehyde 5 and the N-Boc-O-benzyl-(D)-serine (2) are also optimized.
摘要 (
)
可视化
收藏
Three novel eco-friendly anti-creasing agents have been designed and synthesized. The natural silk fabrics treated with them exhibit higher wrinkle recovery degree, strength retention rate and whiteness than those finished with 1, 2, 3, 4-butane tetracarboxylic acid (BTCA). The washing durability of the fabrics treated with the synthesized compounds and BTCA is similar. The chlorine atom, the carboxyl and the s-triazine ring in the synthesized structures and the surface roughness of the silk fabric are all contributive to the improvement of the crease resistance of silk.
摘要 (
)
可视化
收藏
In order to investigate the biological activity of novel bis-pyrazole compounds, a series of N-(3-alkyl-5-(N-methylcarbamyl)-1H-pyrazol-4-yl)-3-alkyl-4-substituted-1H-pyrazole-5-carboxamides were designed and synthesized with ethyl 3-alkyl-1H-pyrazole-5-carboxylate 1 as starting materials. N-Methyl-3-alkyl-4-amino-1H-pyrazole-5-carboxamides 6 were obtained form 1 via 5 steps. 3-Alkyl-4-substitued-1H-pyrazole-5-carboxyl chlorides 4a, 4b, 11a, 11b, 11c or 12 were also obtained from 1 via several steps. Target compounds 7a−7g were obtained after the reaction of 6 with the above 1H-pyrazole-5-carboxyl chlorides. Preliminary bioassay showed some compounds possessing good inactivation effect against TMV (tobacco mosaic virus). Compound 7a showed higher activity superior to Ningnanmycin at a concentration of 5.0×10−4 g/mL and equal activity at 1.0×10−4 g/mL; 7b and 7c showed equal activity to virazole both at concentrations of 5.0×10−4 g/mL and 1.0×10−4 g/mL.
摘要 (
)
可视化
收藏
Efficient reaction of bis-indolyl podand with different aldehydes using Fe(HSO4)3 as catalyst to afford the corresponding new indolyl crown ethers is described. The structures of three distinct isomers have been optimized using HyperChem geometry optimizations. Also percentage of each isomer was obtained with 1H NMR spectroscopy.
摘要 (
)
可视化
收藏
A simple synthesis of highly functionalized 2,5-diaminofurans based pyrimidine derivatives from 1-(carboxymethyl)uracil via a multi-component reaction is described. The reactive 1:1 intermediate produced from the reaction of tert-butyl isocyanide and dialkyl acetylenedicarboxylates was trapped at room temperature by 1-(carboxymethyl)uracil derivatives to yield polyfunctionalized furan rings in fairly good yields.
摘要 (
)
可视化
收藏
A variety of alkyl-arenes and cyclohexane were converted to the corresponding ketones with NaClO as the oxidant in the presence of 1-glycyl-3-methyl imidazolium chloride-copper (II) complex. This method contains simplified product isolation and catalyst recycling, affording benzylic C-H oxidation of alkyl-arenes imparting high yield of ketones. Furthermore, complex could be reused seven times without a significant loss of its catalytic activity.
摘要 (
)
可视化
收藏
A series of novel azo disperse dyes were synthesized by coupling reaction of 4-benzyloxyphenol with diazotized p-substituted aniline derivatives as diazo components. These compounds were characterized by spectroscopic techniques and elemental analysis. Ionization constants, pKa, for these dyes were determined using electronic spectroscopic method.
摘要 (
)
可视化
收藏
A series of novel Schiff bases bearing triazole structure were synthesized and characterized by IR and NMR. Mn(OAc)2/Schiff base efficiently catalyzed Henry reaction of nitroalkanes with aldehydes to produce the corresponding products of β-nitroalcohols, under mild conditions with high yields (up to 99 %). A reaction mechanism is proposed based on the experimental results.
摘要 (
)
可视化
收藏
A facile and efficient approach was developed to access 5, 7-disubstitued thiazolo[5, 4-d]pyrimidine-4, 6(5H, 7H)-diones through condensation of N-substituted 5-amino-4-carbethoxythiazole with structurally diverse isocyanates in the presence of sodium hydride. The easy availability of substrates and tolerance of structural diversity in this reaction make it attractive to be used for construction of library in drug discovery process.
摘要 (
)
可视化
收藏
A series of 2, 6-disubstituted-4-morpholinothieno[3, 2-d]pyrimidine derivatives were synthesized and their cytotoxic activity against H460, HT-29, MDA-MB-231, U87MG and H1975 cancer cell lines were evaluated in vitro. Most of the target compounds exhibited moderate to excellent activity to the tested cell lines. The most promising compound 23 ( 0.84 μmol/L, 0.23 μmol/L, 2.52 μmol/L, 1.80 μmol/L) was 1.1, 2.9, 29,3 and 4.3 times more active than GDC-0941 (0.87 μmol/L, 0.66 μmol/L, 73.8 μmol/L, 7.77 μmol/L) against H460, HT-29, MDA-MB-231 and U87MG cell lines, respectively.
摘要 (
)
可视化
收藏
A series of benzimidazole derivatives have been designed, synthesized and evaluated for H1 antihistamine activity. Six compounds have showed potent antihistamine H1 activity. The primary SAR analysis indicated that benzyl or benzilidinyl substituted on the exo-nitrogen atom and C2 of the benzimidazole were significant. Further experiments indicated that compounds 17d displayed excellent activity to reduce mast cell degranulation, moderate anti-PAF activity and decreased potency on hERG compared to astermizole. Hence compound 17d could serve as anti-allergic agents for further development.
摘要 (
)
可视化
收藏
In this study, the electrochemiluminescent(ECL) behavior of Nickel(II) tetrasulfophthalocyanine (NiTSPc) / H2O2on a heated indium tin oxide(ITO) electrode was investigated. The effect of pH value, electrochemical scan mode, concentration of NiTSPc and electrode surface temperature on the ECL intensities had been studied in detail. Based on the fact that the ECL of NiTSPc can be greatly enhanced by hydrogen peroxide at the ITO electrode, a new ECL biosensor for hydrogen peroxide has been developed. The possible mechanism for the ECL of NiTSPc has been proposed also.
摘要 (
)
可视化
收藏
A rapid and practical method for direct detection of zidovudine in high performance anion exchange chromatography (HPAEC) has been developed with integrated pulsed amperometric detection (IPAD). Dionex AS18 (250 mm × 2 mm) and AG18 (50 mm × 2 mm) columns and 11 mmol/L NaOH solution were used for separation. Multi-step potential waveform parameters were optimized to maximize the signal-to-noise ratio(S/N). Utilizing an optimized waveform, the repeatability (intra-day) precision and intermediate (inter-day) precision are obtained with relative standard deviation (RSD) of 1.88, 2.27, respectively. The limit of quantification (LOQ) and limit of detection (LOD) were found to be 9.70, 3.0 ng/mL, respectively, with correlation coefficients of 0.9992 over concentration range 0.01−10 µg/mL. The present method was successfully applied to the determination of zidovudine in human plasma. The recoveries of plasma sample spiked by 0.7 µg/mL, 2.7 µg/mL obtained were 95.3 %–101.5 %, with relative standard deviation (RSD) of 2.54 %, 2.21 %, respectively.
摘要 (
)
可视化
收藏
A new electrochemical sensor for determination of isoproterenol (IP) is described. The sensor is based on carbon paste electrode (CPE) modified with 5-amino-2',4'-dimethoxybiphenyl-2-ol (5ADMB) and takes the advantages of carbon nanotubes (CNTs). Under the optimum pH of 7.0, the oxidation of IP occurs at a potential about 210 mV less positive than that of the unmodified CPE. The oxidation currents increased linearly with two concentration intervals of IP, one is 0.09 to 20.0 μmol/L and, the other is 20.0 to 400.0 μmol/L. The detection limit (3σ) obtained by square wave voltammetry (SWV) was 39.0 nmol/L. The practical application of the modified electrode was demonstrated by determining IP in IP ampoule, urine and human blood serum samples.
摘要 (
)
可视化
收藏
A monolithic polymer column with mixed-mode interaction was prepared by in situ polymerization in a 1000 µL pipette. Two kinds of monomers, butyl methacrylate (BMA) and 2-(dimethylamino)ethyl methacrylate (DMAM) were applied to constructing the mixed-mode interaction of monolithic polymer column. Its solid-phase extraction properties for liquiritigenin (LQG) were evaluated by high performance liquid chromatography (HPLC) with a gradient elution procedure. After the extraction procedure was optimized, the maximum binding capacity and extraction recovery following the optimal extraction procedure were investigated. Calibration curve was expressed as A=65.9C+4.53 (r2 =0.998) with a linear range of 0.151~1.80 µg/mL. The experimental results indicate that the monolithic polymer pipette presents good extraction efficiency for LQG. It can be envisaged that the developed monolithic polymer pipette possesses the potential for its application to the enrichment of other flavonoids compounds being similar to the structure of LQG.
摘要 (
)
可视化
收藏
We used whole-tree agarwood-induction technology to produce agarwood from Aquilaria sinensis trees within 20 months, and evaluated the quality of this agarwood. The results showed its characteristics were similar to those of high-grade wild agarwood in terms of texture, chemical constituents, essential oil content, and ethanol-soluble extract content, with the lattermost quality far surpassing the requirement of traditional Chinese medicine agarwood, as indicated in Chinese Pharmacopoeia 2010. To the best of our knowledge, this is first study to show that high-quality agarwood can be produced in whole A. sinensis trees via a chemically induced technology.
摘要 (
)
可视化
收藏
Five triorganotin(IV) (1-5) complexes of cinnamic acid, (Z)-2-acetamido-3-phenylacrylic acid, 3-methylbut-2-enoic acid, and 2,2-diphenylacetic acid have been synthesized and characterized by 1H- 13C- 119Sn-NMR, UV, and IR. The spectroscopic investigation demonstrated that the carboxylate group acts as a monodentate ligand in triorganotin(IV) compounds. Five triorganotin(IV) complexes were screened against the log phase culture of Mycobacterium tuberculosis H37Rv by colorimetric method using XTT dye as growth indicator. The MICs were found to be 0.08 and 1.25μg/mL.
摘要 (
)
可视化
收藏
Cationic fluorinated acrylate latex was prepared via semi-continuous emulsion copolymerization of cationic monomer and other monomers. The resultant latex and its film were characterized with dynamic light scattering detector and contact angle meter. Influences of amount of DMDAAC on the properties of resultant latex and its film were investigated in detail. Results show that the particle size of the latex has the minimum value and the zeta potential of the latex is increased when the amount of DMDAAC is increased. In addition, the particle size of the latex is unimodal distribution when the amount of DMDAAC is not more than 2.5 %. However, the particle size of the latex is bimodal distribution when the amount of DMDAAC is more than 2.5 %. The contact angle is varied slightly with the increase of amount of DMDAAC when it is not more than 2.5 %. Nevertheless, the contact angle is decreased with the increase of the amount of DMDAAC when it is more than 2.5 %.
摘要 (
)
可视化
收藏
By retaining the native distal His64 in sperm whale myoglobin (Mb), a second distal histidine was engineered in Mb by mutating Leu29 to His29. The resultant mutant of L29H Mb exhibits an unusual enhanced peroxidase activity with a positive cooperativity in comparison to that of wild type Mb. The new enzyme with two cooperative distal histidines has not been found in native peroxidase, which emphasizes a creation of the rational protein design.
摘要 (
)
可视化
收藏
Magnetic powder resin Q150 with high specific surface area of 1074 m2/g was prepared by the membrane emulsification-suspension polymerization technique. Adsoption of tetracycline on the obtained sorbent Q150 was evaluted by using the granule resin (GR) XAD-4, the powder activated carbon (PAC) 1240AC and the granule activated carbon (GAC) HD4000 for comparison. It was found that Q150 had a larger adsorption capacity, faster kinetic and easier regeneration under alkaline condition. The results suggested that the powder resin (PR) Q150 would be a promising sorbent for removing antibiotics and even other organic micropollutants from the aquatic environment.
摘要 (
)
可视化
收藏
The binary random in-chain silyl-hydride multi-functionalized poly(styrene/butadiene/isoprene and dimethyl[4-(1-phenylvinyl) phenyl]silane) (PS-DPESiH, PB-DPESiH, PI-DPESiH) copolymers were successfully synthesized. These functionalized copolymers were prepared in hexane with n-BuLi as the initiator at 50 °C for 4 h. The silyl-hydride groups were introduced into polymer backbones quantitatively by living anionic polymerization. The copolymers were determined through 1H-NMR, size exclusion chromatography (SEC) and differential scanning calorimetry (DSC) techniques, while the number of silyl-hydride groups was calculated and discussed.
摘要 (
)
可视化
收藏
Polypropylene/poly(butyl methacrylate) (PP/PBMA) blends were prepared by diffusion and subsequent polymerization of butyl methacrylate (BMA) in commercial isotactic polypropylene (iPP) pellets. The diffusion kinetics, diametrical distribution of PBMA in a pellet and phase morphology of a typical PP/PBMA blend were investigated.
