A series of new herbicidal sulfonylurea compounds were investigated aiming at developing a three-dimen-sional quantitative structure-activity relationship (3D-QSAR) model using the CoMFA technique. On this base, some molecular structures were modified to improve their activities. A model of the target acetolactate syntheses (ALS) en-zyme was established for the first time, which is useful to design and synthesis of new ALS enzyme inhibitor.

In search of novel pyrazole derivatives with bloactivity, a se-ries of 3-methyl-1 H-pyrazole-4-caboxylic ester derivatives were synthesized via a-oxoketene dithioacetals as starting ma-terial. The structures of all compounds prepared were con-firmed by 1HNMR, IR, MS and elemental analyses. Prellml-nary bioassays indicated that some compounds showed fungici-dal activity against wheat rust, phoma asparagi and antiviral activity against TMV.

磺酰脲类除草剂具有对环境友好和超高效的特点。本文采用x．衍射谱对其绝对构型进行分析，首次发现分子内氢键的存在。采用各种理论和软件计算，活性结构应符合三点要求：（a）分子内氢键使杂环和脲之间形成一个共轭体系；（b）羰基氧、磺酰氧和杂环氮形成分子中三个负电中心；（c）在磺酰胺与苯邻位取代基之问形成一个空穴。根据以上结论，构建了一个卡口模型，较合理地解释了磺酰脲类除草活性的构效关系。建立了一个虚拟靶酶A工S的模拟作用模型，供进一步分子设计心抑制剂，包括一些非磺酰脲类先导化合物时参考。

A study of some sulfonylureamolecules with consideration of watermolecules as its solvent was undertaken. The influence of the water molecules on the structure-activity relationship of the 35 sulfony-lurea molecules was discussed. By supper-imposition of structural sulfonylmolecules, a molecular RM S was correlated with p I 50, which denotes that the configuration difference in water solution is one of the reasons which causes the difference in bioactivity.

The single-crystal structure of neodymium chloride-ribopyranose pentahydrate, NdCl3·C5H10O5··5H2O was determined to have Mr=490.80, a=9.138(11), b=8.830(10), c=9.811(11) Å,β=94.087(18)°, V=789.7(16) Å3, P21, Z=2,μ=0.71073 Å and R=0.0198 for 2075 observed reflections. The ligand of the title complex was observed in a disordered state and two molecular configurations of NdCl3·C5H10O5 ·5H2O were found in the single crystal as a pair of isomers. Both ligand moieties of the two molecules are ribopyranose forms, providing three hydroxyl groups in ax-eq-ax orientation for coordination. One ligand of the pair of isomers is b-D-ribopyranose in the 1C4 conformation, and the other is a-D-ribopyranose in the 4C1 conformation. The Nd3+ion is nine-coordinated with five Nd-O bonds from water molecules, three Nd-O bonds from hydroxyl groups of the ribopyranose and one Nd /Cl bond from chlorideion. The hydroxyl groups, water molecules, chlorideions form an extensive hydrogen-bond network. The IR spectral C-C,O-H,C-O and C-O-H vibrations were observed to be shifted in the complex and the IR results are in accordance with those of X-ray spectroscopy.