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.

In search of new ALS inhibitors without the previous knowledge of receptor crystal structure, DISCO module was appfied to produce 3D-pharmacophore models, which provided information to design novel molecules by 3D-datahase searching. Then a number of molecules were synthesized. Several of them have some ALS inhibitory activities.

A new strategy was devised to stereo-speclfically introduce various building blocks, mainly heterocydes such as pyri-midines and trlnzlnes onto a multi-hydroxy molecule. A glu-copyranoside was chosen as a target scaffold. Two polymer-based protective reagents were jointly integrated in the imple-mentation of the strategy. It was found that in the a-D-glu-copyranoside, which has four free hydroxyl groups within the same molecule, its 4, 6-di-OH could be simultaneously pro-tected by polystyryl boronie acid, which left the 2, 3-di-OH free for substitution. Due to the steric effects within the molecule, the 2-OH is much more liabile to electrophilic stub-stitutlon. Thus the first and the second building blocks could be introduced regioselectlvely onto the 2-OH and the 3-OH positions. After a facile deprotectlon, the 4,6-di-OH were left free and by application of a second protecting reagent-polystyryltrityichlorlde onto 6-OH, a third building block was introduced onto the 4-OH position. After further deprotec-tion, the fourth building block was later introduced onto the 6-OH position. The new strategy was successfully applied in the combinatorial synthetds by application of the split-mix technique. The respective eleven small Ebraries were obtained and confirmed by I-IPI_~MS and NMR. Some preliminary results on chemical structure/herbicidal activity relationship were discussed.

用比较分子力场分析（CoM FA）方法和比较分子相似性指数分析（CoM S IA）方法研究了21个2（1H）-喹啉-2, 4-二酮类化合物抗小麦锈病的三维定量构效关系（3D2Q SAR），发现用CoM FA方法可以找到最佳的3D-Q SAR模型，并通过量子化学从头计算的方法研究了不同活性化合物的前线轨道及静电势分布图的差异。所得构效关系模型为发现更高活性的化合物提供理论指导。

Some series of 2-alkyl (alkythio)-5-((4-chloro)-3-ethyl-1-methyl-1H-pyrazole-5-yl)-1,3,4-oxadiazoles (thiadiazoles) were prepared as potential fungicides. Their fungicidal activity was evaluated against rice sheath blight, which is a major disease of rice in China. Structure-activity relationships for the screened compounds were evaluated and discussed. It was found that 5-(4-chloro-3-ethyl-1-methyl-1H-pyrazole-5-yl)-1,3,4-thiadiazole-2-thione has the higher fungicidal activity.

3-(p-methyl)anilinomethylidene-6-aryl-5,6-2H-dihydropyran-2,4-dione was selected as the model reactant compound to study the catalytic hydrogenation of 3-anilinomethylidene-6-aryl-5,6-2H-dihydropyran-2,4-diones by the AM1 semi-empirical method. Molecular information such as net charges, bond orders, values of frontier orbital energies, composition, proportions and bonding contribution was acquired and analyzed. Thus, possible reactive sites were proposed and the reaction mechanism was postulated via two different pathways. The postulated intermediates and products were also computed using the AM1 method. Their heat of formation values and energies of HOMO/LUMO/SOMO indicate that the mechanism of catalytic hydrogenation of 3-anilinomethylidene-6-aryl-5,6-2H-dihydropyran-2,4-diones is hydrogenolytic cleavage on a dihydropyrandione ring, not the simple addition of a CyC double bond. Therefore, the experiment result is elucidated theoretically.