N′-5-四唑基-N-芳甲酰基硫脲的合成及其生物活性研究(I)

为寻找新的高活性农药 ,根据生物等排原理 ,设计合成了 10种未见文献报道的N′ 5 ( 1H 1,2 ,3 ,4 四唑基 ) N 芳甲酰基硫脲类化合物 .它们的结构经IR ,1HNMR和元素分析确证 .初步的生物活性测定结果表明 ,部分化合物具有优良的除草活性或植物生长调节活性 .     

Preparation and separation of all possible rotamers of a stereochemical analog of meso-tartaric acid: optically inactive and optically active isomers of (R,S)-2,2′-bis(methoxycarbonyl)-6,6′-dimethyl-9,9′-bitriptycyl

All the three possible rotamers of the title compound were separated by chromatography, and unambiguously identified by NMR and X-ray analysis. One of the isomers was optically inactive C_i conformation. The other optical active forms were resolved to give a pair of enantiomers, which were characterized by optical rotation and CD spectra. Thus the optical inactivity of a compound such as meso-tartaric acid that can take C_i conformation in solution, is now ascribed to that the molecule has an optically inactive C_i conformer and equal amounts of optically active conformers, that are enantiomers, in solution.     

Diclobutrazol的合成及其生物活性研究

Ｄｉｃｌｏｂｕｔｒａｚｏｌ的合成及其生物活性研究张洪奎，廖联安，陈明德，叶向阳，郭奇珍（厦门大学化学系厦门３６１００５）关键词：Ｄｉｃｌｏｂｕｔｒａｚｏｌ，相转移催化，合成，生物活性Ｄｉｃｌｏｂｕｔｒａｚｏｌ（１）俗名粉锈清，是一种广谱内吸性杀菌剂，...     

An <Emphasis Type="BoldItalic">in silico</Emphasis> approach for screening flavonoids as P-glycoprotein inhibitors based on a Bayesian-regularized neural network

Summary P-glycoprotein (P-gp), an ATP-binding cassette (ABC) transporter, functions as a biological barrier by extruding cytotoxic agents out of cells, resulting in an obstacle in chemotherapeutic treatment of cancer. In order to aid in the development of potential P-gp inhibitors, we constructed a quantitative structure–activity relationship (QSAR) model of flavonoids as P-gp inhibitors based on Bayesian-regularized neural network (BRNN). A dataset of 57 flavonoids collected from a literature binding to the C-terminal nucleotide-binding domain of mouse P-gp was compiled. The predictive ability of the model was assessed using a test set that was independent of the training set, which showed a standard error of prediction of 0.146 ± 0.006 (data scaled from 0 to 1). Meanwhile, two other mathematical tools, back-propagation neural network (BPNN) and partial least squares (PLS) were also attempted to build QSAR models. The BRNN provided slightly better results for the test set compared to BPNN, but the difference was not significant according to F-statistic at p = 0.05. The PLS failed to build a reliable model in the present study. Our study indicates that the BRNN-based in silico model has good potential in facilitating the prediction of P-gp flavonoid inhibitors and might be applied in further drug design.     

Synthesis, Structure and Biological Activities of Novel Triazole Compounds Containing N,N-Dialkyldithiocarbamate Moiety

Introduction As an important type of fungicides, triazole compounds are highly efficient, low poisonous and inward absorbent.1-3 At present, the studies on triazole derivatives are mainly concentrated on compounds with triazole as the only active group. The report of triazole compounds that contain both triazole group and other active group in a single molecule has rarely been found. Dialkyl-substituted dithiocarbamate salts have also shown interesting biological effects.4 N,N-Dialkyldithio-…     

Catalytic activity of tetracoordinated stereochemically flexible Ni(II) bis(5-thiopyrazol-4-aldiminates) in the dimerization of propylene

The catalytic activity of Ni(II) bis-(5-thiopyrazol-4-aldiminates) was found to be related to the stereochemical flexibility of these compounds in the dimerization of propylene. The propylene conversion decreases with decreasing stereochemical flexibility of the complexes resulting from an increase in the bulk of the substituent at the coordinated nitrogen atom of the NiN₂S₂ chelate ring.Institute of Inorganic and Physical Chemistry, Academy of Sciences of Azerbaidjan, 370143 Baku. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2667–2670, November, 1992.     

Structural study of pyrimidine nucleoside analogues. I: Molecular mechanics and semiempirical calculations of 2′-deoxy-2′-fluoroarabinofuranosyluracils

Molecular mechanics (MM) calculations have been performed on the title compounds. For the MM minimum energy conformation obtained by conformational analysis, molecular orbital (MO) calculations (MNDO and AM1) have also been performed. The geometries obtained have been compared with the experimental ones extracted from the Cambridge Structural Database (CSD). A qualitative structure-activity relationship has been pointed out based on the electrostatic potentials calculated at different positions on the electronic surface.     

2-氰基-3-甲硫基-3-取代甲氨基丙烯酸酯类化合物的合成及其除草活性

A series of 2-cyano-3-methylthio-3-substituted methylaminoacrylates were synthesized as herbicidal inhibitors of photosystem Ⅱ （PSⅡ） electron transport, in order to estimate the effect of fluorine atom, pyridyl group, chirality and ester chain on activity. The important intermediate 2-fluoro-5-aminomethylpyridine was synthesized with high yield. The bioassay results showed that most of rifle compounds had high herbicidal activity in postemergence treatment. The introduction of an a-methyl into the 3-substituted methylamino could improve the activity notably. The replacement of hydrogen by chlorine or fluorine group and phenyl by pyridyl group showed different effects, and at the same time, the ester chain affected the activity too.     

Pitzer model parameters for sparingly soluble salts from solubility measurements. The systems TlCl+SrCl2+H2O and TlCl+BaCl2+H2O at 25°C

The solubility of thallium(I) chloride has been determined in aqueous solutions of strontium chloride and barium chloride at concentrations up to 1.5 mol kg^–1. The data were analyzed using Pitzer's equations without making explicit assumption of association to ion pairs by assuming =3 instead of =2, with the ⁽¹⁾ term for TlCl being equivalent to the ⁽²⁾ term for 2-2 electrolytes. Best values of ⁽⁰⁾ and ⁽¹⁾ for TlCl are recommended together with K _s , the activity solubility product. These were used to fit the present solubility data and derive the Pitzer model mixture parameters relevant to the systems, _fTIN and _fTINCl (N=Sr, Ba). Mixture parameters for TlCl+MCl+H₂O systems are also derived to complete the parameter base. The fit of the experimental data was found to be worse when higher-order terms for asymmetrical mixing were included in the analysis. Activity coefficients for thallium(I) chloride in the mixtures are derived.