49 resultados para 1-methyl-1


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The crystal structure of the title compound, C19H15FN6OS, is stabilized by a weak intermolecular C-(HN)-N-... hydrogen-bond interaction.

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In the title compound, C12H10FN7S, the dihedral angles made by the plane of the thione-substituted triazole ring with the planes of the other triazole ring and the benzene ring are 71.94 (3) and 40.10 (2)degrees, respectively. Inter- and intramolecular hydrogen-bond and pi-pi stacking interactions stabilize the structure.

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A novel triazole derivative 4-(2-hydrobenzylideneamino)-3-(1, 2, 4-triazol-4-ylmethyl)-1H-1, 2, 4-triazole-5 (4H)-thione(1) was synthesized and characterized using elemental analysis, MR, and H-1 NMR, and its crystal structure was determined via X-ray single crystal diffraction analysis. Crystal data: monoclinic, P2 (1)/c, a = 0.83335 (9) nm, b = 1. 49777 (16) run, c = 1. 14724 (12) nm, beta = 107. 990 (2)degrees, D = 1. 470 Mg/m(3), and Z = 4. The geometries and the vibrational frequencies were determined using the density functional theory(DFT) method at the B3LYP/6-31G* level. To demonstrate the accuracy of the reaction route of compound 1, one of the important intermediates was also tested using the same method. The structural parameters of the two compounds calculated using the DFT study are close to those of the crystals, and the harmonic vibrations of the two compounds computed via the DFT method are in good agreement with those in the observed IR spectral data. The thermodynamic properties of the title compound were calculated, and the compound shows a good structural stability at normal temperature. The test results of biological activities show that it has a certain bactericidal ability.

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A new labeling reagent, 1-(2-naphthyl)-3-methyl-5-pyrazolone (NMP), coupling with liquid chromatography (LC) with electrospray ionization mass spectrometry (ESI-MS) for the detection of carbohydrates from a famous Tibetan medicine is reported. Carbohydrates were derivatized to their bis-NMP-labeled derivatives. The method, in conjunction with a gradient elution, offered a baseline resolution of carbohydrate derivatives on a reversed phase Hypersil ODS-2 column. The carbohydrates such as mannose, galacturonic acid, glucuronic acid, rhamnose, glucose, galactose, xylose, arabinose, and fucose could be successfully detected by UV and ESI-MS. Derivatives showed intense protonated molecular ion at m/z [M+H]+ in positive ion mode. The mass to charge ratios of characteristic fragment ions at m/z 473.0 could be used for the accurately qualitative identification of carbohydrates; this characteristic fragment ion was from the cleavage of C2-C3 bond in the carbohydrate chain giving the specific fragment ions at m/z [MH-CmH2m+1Om-H2O](+) for pentose, hexose, and glyceraldehydes, and at m/z [MH-CmH2m-1Om+1-H2O](+) for alduronic acids, such as galacturonic acid and glucuronic acid (m=n-2, n is carbon atom number of carbohydrate). Compared with the traditional 1-phenyl-3-methyl-5-pyrazolone (PMP) reagent, currently synthesized NMP show the advantage of higher sensitivity to carbohydrate compounds with UV and ESI-MS detection.

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A novel labeling reagent 1-(2-naphthyl)-3-methyl-5-pyrazolone (NMP) coupled with capillary electrophoresis (CE) with DAD detection for the determination of carbohydrates has been developed. The chromophore in the 1-phenyl-3-methyl-5-pyrazolone (PMP) reagent is replaced by naphthyl functional group, which results in a reagent with very high molar absorptivity (epsilon(251nm) = 5.58 x 10(4) L mol(-1) cm(-1)). This pen-nits NMP-labeled carbohydrates to be detected with UV absorbance in standard 50-mu m-i.d. fused silica capillaries by zone electrophoresis. in this mode, nanomolar concentrations of detection limits are obtained. The method for the derivatization. of carbohydrates with NMP is simplified. The derivatization reaction is rapid and mild in the presence of ammonia catalyst without further transfer steps. Nine monosaccharide derivatives such as mannose, galacturonic acid, glucuronic acid, rhamnose, glucose, galactose, xylose, arabinose and fucose can successfully be detected in CE mode. Good reproducibility can be obtained with relative standard deviation (R.S.D.) values of the migration times and peak area, respectively, from 0.44 to 0.48 and from 3.2 to 4.8. Furthermore, the developed method has been successfully applied to the analysis of carbohydrates in the hydrolyzed rape bee pollen samples. (C) 2008 Published by Elsevier B.V.

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This paper describes the simultaneous determination of allantoin, quercetin, and 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCCA) in Nitraria tangutorum Bobr seed by HPLC-APCI-MS and CE (capillary electrophoresis) methods. The final optimized chromatographic conditions were investigated in a reversed-phase Eclipse XDB-C8 column (150 x 4.6 mm, 5 mu m). A seventeen-minute gradient elution, (A: aqueous acetonitrile 20% (v/v); B: aqueous acetonitrile 60% (v/v); C: pure acetonitrile 100%) at a flow rate of 1.0 mL/min was selected for the separation of three natural products with diode array detection (DAD) at 220 nm. A CE experiment was carried out in a fused silica capillary with 32 mmol/L boric acid (pH 10), 32 mmol/L SDS and acetonitrile (10.0%, v/v). The applied potential and temperature was, respectively, set at 19 kV and 25 degrees C. After development, the validation was performed in parallel for HPLC and CE, with the same standards and sample to avoid differences due to the manipulation. The validation parameters of both techniques were adequate for the intended purpose.

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Twelve novel zidovudine derivatives were prepared by modifying 5 '-hydroxyl group of sugar moiety (1-8) and 5-methyl group of thymidine nucleus (9-12) and characterized spectrally. The compounds were evaluated for anti-HIV-1, antitubercular and antibacter

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The genome segments 1, 2, and 3 of the grass carp reovirus (GCRV), a tentative species assigned to genus Aquareouirus, family Reouiridae, were sequenced. The respective segments 1, 2, and 3 were 3949, 3877, and 3702 nucleotides long. Conserved moths 5' (GUUAUUU) and 3' (UUCAUC) were found at the ends of each segment. Each segment contains a single ORF and the negative strand does not permit identification of consistent ORFs. Sequence analysis revealed that VP2 is the viral polymerase, while VPI might represent the viral guanyly/methyl transferase (involved in the capping process of RNA transcripts) and VP3 the NTPase/helicase (involved in the transcription and capping of viral RNAs), The highest amino acid identities (26-41%) were found with orthoreovirus proteins. Further genomic characterization should provide insight about the genetic relationships between GCRV, aquareoviruses, and orthoreoviruses, It should also permit to precise the taxonomic status of these different viruses. (C) 2000 Academic Press.

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Methomyl, an extremely toxic pesticide, is widely used in agriculture. A strain named mdw-1 capable of degrading methomyl rapidly was successfully isolated from activated sludge in this study. It could utilize methomyl as the sole carbon or nitrogen source. The optimal temperature and medium pH for its growth and methomyl biodegradation were 30 degrees C and 7.0, respectively. It was identified as a Paracoccus sp. according to its morphological features, physiological and biochemical characteristics, and phylogenetic analysis based on the sequence of 16S rDNA. Gas chromatography-mass spectrometry (GC-MS) analysis showed that methomyl could be completely transformed to S-methyl-N-hydroxythioacetamidate in 10 h of incubation with the isolate mdw-1.

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Several zeolite catalysts such as SAPO-11, ZSM-11, ZSM-12, etc. were selected to convert I-hexene to branched hexenes in this work. Pore size of the zeolite catalyst plays an important role on the yield and the distribution of branched isohexenes. And the zeolite catalysts with the pore size of 0.6nm are optimum to produce dimethylbutenes (DMB). SAPO-11 zeolite is a suitable skeletal isomerization catalyst, especially in the production of methyl pentenes. Under the following reaction conditions: WHSV=1.0 h(-1), H-2/hexene=8, T=250 degreesC, P=0.2 MPa, the yield of skeletal isohexenes remains above 80% at the prolonged time-on stream of 80 h, accompanying low C5-, C7+ products and low carbon deposition on the catalyst.

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1 初级视觉皮层功能,GABA系统功能在衰老过程中的变化 本章首先对衰老过程中神经形态学和神经电生理学上的研究进行了综述,然后报道了作者的博士学位论文研究工作。实验采用神经电生理的手段,探讨初级视觉皮层(primary visual cortex;V1)功能,以及GABA(gamma-aminobutyric acid)系统功能在衰老过程中的变化。 实验1和2均采用单细胞记录技术,检测了中年猴V1细胞的方位选择性、方向选择性、自发放和最大反应,并与年轻和老年猴进行对比;比较了年轻和老年猴V1细胞的感受野外周抑制能力。在实验3中,我们记录了年轻和中年大鼠在给予GABA直接或间接的激动剂,戊巴比妥钠或氯胺酮{通过拮抗NMDA(N-methyl-D-aspartate)受体}后,其皮层的EEG(electroencephalogram)活动,并分析与年龄相关的差异。结果如下: 实验1:中年猴V1细胞的方向选择性和自发放介于年轻猴和老年猴之间,而方位选择性和最大反应与年龄之间没有相关性。 实验2:感受野外周区的最优刺激明显降低了年轻和老年猴具有高方位选择性细胞的比例。同时,年轻猴所有细胞,以及老年猴高方位选择性细胞具有较高的最大抑制比,与它们相比,老年猴无明显方位偏好细胞的最大抑制比显著降低; 实验3:戊巴比妥钠注射后,在年轻和中年大鼠上,alpha (8-12 Hz) 和beta (12-20 Hz) 频段EEG功率增加,theta (4-8 Hz) 功率减少,这些变化在中年大鼠上较为明显。氯胺酮注射后,中年大鼠theta功率比年轻大鼠具有更大幅度的降低。 我们的结果表明,视觉皮层功能的下调在衰老早期就已发生,其机制可能与抑制系统功能普遍降低有关. 2 奖赏机制,极低频磁场的生物学效应研究 本章首先对自然奖赏和药物成瘾机制、极低频磁场生物学效应,以及极低频磁场对奖赏系统的影响进行了综述,然后报道了作者的博士论文研究工作。实验目的是探讨大鼠眶额叶皮质(orbitofrontal cortex;OFC)活动与食物奖赏刺激的相关性,以及极低频磁场对小鼠空间认知能力的影响。 实验1采用EEG记录技术,检测了大鼠OFC在食物奖赏和渴求过程中EEG各频段的功率变化。在实验2中,使用了一种探索型Y-迷宫实验范式,它仅依赖于啮齿类动物天生的探索欲望,避免了奖赏效应的干扰,利用此新型迷宫,我们检测了25和50 Hz磁场对小鼠空间识别记忆能力的影响。其结果如下: 实验1:大鼠OFC的delta频段(2-4 Hz)EEG活动与食物刺激显著相关,其相对功率在食物渴求时下降,在食物奖赏时升高。 实验2:与短时照射相比,长时的50 Hz磁场照射降低了小鼠对新异臂的探索能力,而25和50 Hz磁场暴露都不影响小鼠的活动力。 本研究表明,食物奖赏与OFC的delta频段EEG活动密切相关,而我们以前发现,大鼠和猴OFC的gamma(20-100 Hz)活动与吗啡成瘾相关,提示了OFC在自然奖赏和药物成瘾中具有不同的作用;另外,本实验首次证明,极低频磁场损害了小鼠不依赖于奖赏系统的空间认知能力,而我们先前发现,极低频磁场可以强化吗啡诱导的条件化位置偏好,从而说明极低频磁场对吗啡成瘾具有独特的生物学效应。

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The crystal structure of Er(PM)(3)(TP)(2) [PM = 1-Phenyl-3-methyl-4-isobutyryl-5-pyrazoloiie, TP = triphenyl phosphine oxide] was reported and its photoluminescence properties were studied by UV-vis absorption, excited, and emission spectra. The Judd-ofelt theory was introduced to calculate the radiative transition rate and the radiative decay time of 3.65 ms for the I-4(13/2) -> I-4(15/2) transition of Er3+ ion in this complex.