新磺酰脲类化合物除草活性的3D-QSAR分析

用比较分子力场分析 (CoMFA) 方法和比较分子相似性指数分析 (CoMSIA) 方法对所合成的新磺酰脲类化合物的除草活性进行了较为系统的3D-QSAR分析.两种方法所建立的模型对化合物的除草活性预测能力均较好,所得三维等值线图为合成高活性的化合物能提供指导作用     

抗艾滋病药物环尿素类化合物的结构表征及其生物活性的定量预测

提出一种新的结构描述子-按氢分类的电距矢量（H-MEDV），并用于环尿素类 化合物抗人类免疫缺陷病毒（human immuno-deficiency virus，简称HIV）活性预 测，籍以多元线性回归（MLR）建立了H-MEDV与活性之间的相关模型，取得了良好 的结果，相关系数达R = 0.971。另外采用逐步回归（SMR）从原模型参数中选取了 5个参数建立一新模型，其模型相关系数为R = 0.938；继以留一法（Leave-one- out，LOO）进行交互检验，相关系数与之接近，R = 0.908；说明了定量结构活性 相关模型具有很好的稳定性和预测能力。     

光驱动单向分子转子的研究进展

分子转子是分子马达设计的要件, 有关分子转子的讨论已经引起广泛的关注. 主要介绍2003年以来单向转动型分子转子的研究状况, 重点讨论其构效关系和应用方面的最新进展, 展望了分子转子的发展前景并指出其面临的挑战.     

2-嘧啶氧基-N-芳基苄胺类化合物的ALS抑制活性的QSAR研究

乙酰乳酸合成酶(ALS)或乙酰羟酸合成酶(AHAS)存在于植物的生长过程中, 很多此类酶的抑制剂实际上作为除草剂被广泛用于农业生产中. 生物活性测试结果表明, 2-嘧啶氧基-N-芳基苄胺类化合物对ALS具有一定的抑制活性. 在此基础上, 我们用两种三维定量构效关系(3D-QSAR)研究方法: 比较分子立场分析(CoMFA)和比较分子相似性指数分析(CoMSIA), 对该类化合物进行了3D-QSAR研究, 并建立了相关的预测模型. 其中, CoMFA模型的交叉验证相关系数(r_cv²)为0.801, 非交叉验证相关系数(r²)为0.947, 标准偏差(s)为0.136, F值为133.371. CoMSIA模型的r_cv²为0.744, r²为0.883, s为0.202, F值为56.472. 计算结果表明, 2-嘧啶氧基-N-芳基苄胺类化合物与ALS抑制活性有一定的相关性. 获得的CoMFA和CoMSIA模型, 将应用于指导该类化合物的设计.     

紫杉醇构效关系研究新进展

综述了近年来在紫杉醇类似物构效研究中的最新进展,按照紫杉醇的A,B, C,D环修饰的顺序总结了新得到的40余种紫杉醇类似物结构与其生物活性之间的关系。     

An ab initio theoretical study of the stereoisomers of tetrahydrocannabinols

An extensive theoretical study of the stereoisomers of tetrahydrocannabinols has been performed at the ab initio HF/6-31G^* and B3LYP/6-31G^* levels. Effects of solvation were calculated with the Onsager model (with full geometry optimization), SCRF with Tomasi's PCM, and isodensity polarization continuum models. Single-point MP2//HF/6-31G^* calculations were carried out. Frequency calculations for all the isomers at the HF/6-31G^* level and for two natural isomers ¹-THC-RR and ⁶-THC-RR at the B3LYP/6-31G^* level were performed. Our results support the findings of the previous AM1 studies that the orientation of the carbocyclic ring and its C1 substituent with respect to the phenyl group hydroxyl oxygen play the major role in the activity. The calculated values of the LUMO energy (lowest unoccupied molecular orbital) and the hardness of the stereoisomers show that for the trans isomers it is easier to remove one electron from its HOMO (highest occupied molecular orbital) to the LUMO and easier to accept an electron from the receptor binding site than for the cis isomers. Combining geometric features (the orientation of the carbocyclic ring and its C1 substituent with respect to the phenyl group hydroxyl oxygen) with electronic features (LUMO and hardness), we explain the activity differences among the stereoisomers.     

Comparison of 3D quantitative structure-activity relationship methods: Analysis of the in vitro antimalarial activity of 154 artemisinin analogues by hypothetical active-site lattice and comparative molecular field analysis

Two three-dimensional quantitative structure-activity relationship (3D-QSAR) methods, comparative molecular field analysis (CoMFA) and hypothetical active site lattice (HASL), were compared with respect to the analysis of a training set of 154 artemisinin analogues. Five models were created, including a complete HASL and two trimmed versions, as well as two CoMFA models (leave-one-out standard CoMFA and the guided-region selection protocol). Similar r2 and q2 values were obtained by each method, although some striking differences existed between CoMFA contour maps and the HASL output. Each of the four predictive models exhibited a similar ability to predict the activity of a test set of 23 artemisinin analogues, although some differences were noted as to which compounds were described well by either model.     

Strong Antibiotic Activity of the Myxocoumarin Scaffold in vitro and in vivo

The increasing emergence of resistances against established antibiotics is a substantial threat to human health. The discovery of new compounds with potent antibiotic activity is thus of utmost importance. Within this work, we identify strong antibiotic activity of the natural product myxocoumarin B from Stigmatella aurantiaca MYX-030 against a range of clinically relevant bacterial pathogens, including clinical isolates of MRSA. A focused library of structural analogs was synthesized to explore initial structure-activity relationships and to identify equipotent myxocoumarin derivatives devoid of the natural nitro substituent to significantly streamline synthetic access. The cytotoxicity of the myxocoumarins as well as their potential to cure bacterial infections in vivo was established using a zebrafish model system. Our results reveal the exceptional antibiotic activity of the myxocoumarin scaffold and hence its potential for the development of novel antibiotics.     

Total Synthesis and Structure Correction of the Cyclic Lipodepsipeptide Orfamide A

A total synthesis of the cyclic lipodepsipeptide natural product orfamide A was achieved. By developing a synthesis format using an aminoacid ester building block and SPPS protocol adaptation, a focused library of target compounds was obtained, in high yield and purity. Spectral and LC-HRMS data of all library members with the isolated natural product identified the ⁵Leu residue to be d - and the 3’-OH group to be R-configured. The structural correction of orfamide A by chemical synthesis and analysis was confirmed by biological activity comparison in Chlamydomonas reinhardtii, which indicated compound configuration to be important for bioactivity. Acute toxicity was also found against Trypanosoma brucei, the parasite causing African sleeping sickness.