基于去包络线和连续投影算法的枣园土壤电导率光谱检测研究

选取新疆阿拉尔市典型极端干旱区为研究对象,利用土壤高光谱特征对土壤电导率进行反演。为了准确快速检测土壤电导率,通过获取南疆阿拉尔市红枣种植区土壤电导率和高光谱信息,在去包络线处理基础上,分别采用相关性分析法和连续投影算法（SPA）筛选特征波长,并建立特征波长与土壤电导率的偏最小二乘回归模型,使用均方根误差(RMSE)、决定系数（R²）以及相对分析误差（RPD）对不同处理方法的模型效果进行评价。结果表明,基于原始光谱直接使用相关性分析法的预测精度RMSE=0.85566,R²=0.7479,RPD=2.7569;通过去包络线处理使用相关性分析筛选特征波长后,模型的预测精度RMSE=0.44490,R²=0.9500,RPD=6.4510;基于原始光谱使用SPA选择特征波长后,模型的预测精度RMSE=0.31178,R²=0.9707,RPD=8.4445;通过去包络线处理使用SPA选择特征波长后,模型的预测精度RMSE=0.30173,R²=0.9764,RPD=9.3215。综上,说明SPA方法具有较强的特征波长选择能力,基于去包络线处理+SPA的偏最小二乘回归反演模型的预测精度最好,可实现新疆阿拉尔地区土壤电导率的快速检测。     

荒漠草原区土壤水分ELM-ESTARFM遥感反演模型构建与应用

土壤水分的高时空分辨率和高精度评估对干旱监测具有重要意义。为探究我国内蒙古荒漠草原区土壤水分遥感反演最优模型,基于Landsat和MODIS数据进行改进型自适应反射率时空融合（Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model,ESTARFM）,结合下垫面因子、地形因子、气象因子、植被因子等多要素环境因子,通过极限学习机（Extreme learning machine,ELM）和随机森林（Random forest,RF）两种方法构建土壤含水率反演模型,并与Landsat（未进行融合）构建的土壤含水率反演模型进行对比,最终筛选得到最优土壤含水率反演模型,并对研究区不同土地利用类型土壤含水率分布特征进行应用分析。结果表明：归一化植被指数是土壤含水率环境因子相关分析中最重要的预测因子（0～10、10～20、20～30 cm土壤深度处R²=0.85、0.82、0.79）,其次为降水量（R²=0.73、0.68、0.71）、高程（R²=0.71、0.70、0.71）、水体指数（R²=0.69、0.69、0.68）、归一化盐分指数（R²=0.68、0.67、0.65）。与未进行时空融合所构建的模型相比,利用ESTARFM时空融合所构建的模型精度均有所提升,考虑ESTARFM时空融合时,ELM模型的R²、RMSE、MAE分别为0.89、6.58%、3.93%,RF模型的R²、RMSE、MAE分别为0.78、7.25%、4.95%;未考虑ESTARFM时空融合时,ELM模型的R²、RMSE、MAE分别为0.75、7.37%、5.24%,RF模型的R²、RMSE、MAE分别为0.71、7.48%、5.30%。表明ELM模型比RF模型的土壤含水率反演效果更好,且ELM-ESTARFM为土壤含水率反演最优模型。在此基础上,运用改进后的ELM-ESTARFM遥感反演模型监测了乌审旗全域土壤含水率,发现研究区北部和西北部的土壤含水率较高,南部地区的土壤含水率较低;对于不同土壤深度,土壤含水率由大到小依次为耕地、林地、草地、沙地,耕地区域0～10、10～20、20～30 cm土层含水率分别为18.92%、19.34%、21.84%,林地为11.80%、11.87%、12.40%,草地为10.97%、11.02%、12.22%,沙地为5.07%、5.35%、5.67%。     

石羊河流域制种玉米咸淡水轮灌模式 的SWAP模型模拟

为了探究石羊河流域制种玉米的咸淡水轮灌模式,利用2014年田间试验观测资料对SWAP模型进行了参数率定和验证,模拟了不同咸淡水轮灌模式下的土壤水盐平衡,并筛选出了较优的咸淡水轮灌模式,预测了较长时期土壤盐分动态变化及制种玉米产量。结果表明：SWAP模型率定与验证过程中,土壤含水量的均方误差(RMSE)值在0.05 cm³·cm^-3以下,平均相对误差（MRE)值在15%以下;土壤含盐量的RMSE值在4.2 mg·cm^-3以下,MRE值在25%以下;制种玉米产量的RMSE值在380 kg·hm^-2以内,MRE值在10%以下,率定和验证后的SWAP模型可用于研究区咸水与淡水灌溉的模拟与预测。3.0 g·L^-1微咸水条件下采用2次淡水、1次咸水和1次淡水、2次咸水的轮灌方式以及6.0 g·L^-1咸水条件下采用2次淡水、1次咸水的轮灌方式为研究区制种玉米的较优轮灌模式,这3种较优咸淡水轮灌模式下的土壤盐分累积量较少,并且能够提高制种玉米的产量。3种较优轮灌模式模拟预测结果显示,在模拟期内土壤含盐量增幅不大,能够达到平稳,不会造成土壤盐渍化,制种玉米减产幅度较小,制种玉米产量能够保持平稳。     

含1,2,4-三唑基和肟醚基的N-甲氧基氨基甲酸酯类化合物的合成及杀菌活性

通过(Z)-1-(取代苯基)-2-(1H-1,2,4-三唑-1-基)乙酮肟与N-甲氧基-N-(2-溴甲基苯基)氨基甲酸甲酯反应,合成了11个新的含有三唑基和肟醚基的N-甲氧基氨基甲酸酯类化合物( V1 ~ V11 ),其结构均经1H NMR、IR、LC/MS及元素分析确证。对合成的化合物进行了离体抑菌活性实验,结果表明:在50 mg/L下,所有化合物对小麦赤霉病菌Gibberella zeae (Schw.)Petch、稻瘟病菌Pyricularia oryzae Cav.和黄瓜灰霉病菌Botrytis cinerea Pers.都有一定的抑菌活性,其中 V4 、 V11 对稻瘟病菌的抑菌活性分别达96.5%和96.7%,对黄瓜灰霉病菌的抑菌活性分别达到95.9%和90%。     

基于随机森林回归的油菜叶片SPAD值遥感估算

以西北地区典型经济作物油菜为研究对象，利用SVC-1024i型便携式光谱仪和SPAD-502型叶绿素仪测定了油菜不同生育期的叶片光谱反射率和SPAD值。通过分析油菜原始光谱及10种光谱指数与SPAD值的相关关系，基于光谱指数构建了不同生育期油菜叶片SPAD值随机森林回归（RF）估算模型，并利用独立样本对所建模型进行验证，同时结合传统的一元线性回归模型和多元逐步回归模型与其进行比较。结果表明：油菜叶片SPAD值在全生育期内呈现出先上升后下降的趋势；各光谱指数在不同生育期及全生育期与SPAD值的相关性均达到0.01水平的显著相关；基于光谱指数构建的随机森林回归模型在油菜各个生育期及全生育期建模和预测结果明显优于同期的传统回归模型，建模R²达0.90以上，验证R2达0.81以上，RMSE在1.571~5.004，RE在2.66%~13.22%，是油菜叶片SPAD值的最优估算模型。     

寒地水稻叶片SPAD值与稻米蛋白质含量的关系

为揭示寒地水稻叶片SPAD值及其衍生值与稻米蛋白质含量的关系，于2020—2021年在水稻拔节期（T1）、孕穗期（T2）、齐穗期（T3）测定顶部3片叶的SPAD值，依据盆栽试验（试验1和试验2）的数据资料建立SPAD值衍生指标与稻米蛋白质含量之间的关系模型，利用大田试验（试验3）数据资料对建立的模型进行验证。结果表明，2020年氮肥试验中A8水平（氮素施用量362.07 kg·hm^-2）稻米蛋白质含量较A1~A7水平（A1~A7氮素施用量分别为0、51.72、103.45、155.17、206.90、258.62、310.35 kg·hm^-2）分别极显著增加34.55%、27.44%、26.39%、22.19%、18.07%、14.39%、12.23%，而A8水平食味值较A1~A7水平分别极显著降低8.10%、5.06%、4.99%、4.10%、3.45%、2.96%、2.28%，2021年蛋白质含量、食味值变化趋势与前者相同。两年品种试验6个品种稻米蛋白质含量比较中，C6品种（三江6号）蛋白质含量较C5（龙粳21）、C4（垦粳8号）、C3（龙稻203）、C2（松粳16）、C1（松粳22）分别极显著提高2.99%、12.23%、10.43%、5.04%、15.63%，C6食味值较C5、C4、C3、C2、C1分别极显著降低1.17%、12.09%、3.54%、2.89%、7.93%。品种差异及施氮量对不同生育时期水稻顶部3 片叶的SPAD值分布规律有较大影响，但水稻冠层叶片出现的两次“黑黄交替”现象不受品种的影响，其中单片叶的SPAD值受品种差异的影响，与蛋白质含量不存在相关性，借助指标SPAD_(L1+L2+L3)/3、SPAD_L2×L3/mean可有效降低品种及环境差异对蛋白质含量预测结果的影响，指标SPAD_(L1+L2+L3)/3与蛋白质含量在T1~T3期（拔节期、孕穗期、齐穗期）的拟合方程分别为：Y=0.24X-1.94 ，R²为0.75^**、Y=0.25X-1.69，R²为0.74^**、Y=0.27X-2.45 ，R²为0.72^**；SPAD_L2×L3/mean拟合方程分别为：Y=0.22X-1.05 ，R²为0.75^**、Y=0.27X-2.43， R²为0.72^**、Y=0.26X-2.24，R²为0.72^** （Y为蛋白质含量，X为SPAD衍生值），拟合方程均达到极显著水平。稻米蛋白质含量和食味值评分变现为线性负相关，回归方程为Y=-4.21X+113.32（Y为食味值，X为蛋白质含量），拟合优度R²=0.93^**，达到极显著水平。综上，借助指标SPAD_(L1+L2+L3)/3和SPAD_L2×L3/mean能够实现快捷、无损和实时预测稻米蛋白质含量，在一定程度上判定出稻米蒸煮食味品质的优劣，达到按质收获以及对品质实时监测的要求，促进优质寒地水稻的可持续发展。     

基于AquaCrop模型的塔额盆地夏玉米节水潜力分析

以AquaCrop模型为基础,结合2021—2022年塔额盆地夏玉米实测数据,对模型部分保守参数和产量模块的标准水分生产力（WP^*）和参考收获指数（HI₀）进行校准与验证,通过设置起始灌水时间、灌溉定额和灌水周期三因素交叉试验,对夏玉米进行产量模拟,分析其产量与作物水分利用效率受灌溉定额和起始灌水时间的影响程度,在产量和作物水分利用效率均为较高值的前提下选择最优灌溉方案。以实际夏玉米播种面积为参考值,模拟并预测2022年及未来4年在不同灌溉方案下的夏玉米产量和节水总量,并依此分析塔额盆地夏玉米节水潜力。结果表明：（1）对AquaCrop模型作物生长模块主要参数、土壤水分胁迫参数和产量模块参数WP^*和HI₀进行参数率定,最终产量模块参数选择WP^*=35 g·m^-2、HI₀=43%,2021年和2022年产量模拟相对误差值分别为1.26%和1.07%。（2）结合模型模拟得出最优灌溉方案如下：起始灌水时间5月20日,灌溉定额470 mm,灌水周期7 d,灌水11次,作物水分利用效率2.005 kg·m^-3,产量9.423 t·hm^-2。（3）以2022年为现状水平年,最优灌溉方案下,现状水平年和未来水平年（2022—2025年）可分别实现节水量2.1338×10⁵、2.1826×10⁵、2.1992×10⁵ m³和2.2306×10⁵ m³。     

基于条件植被温度指数的冬小麦主要生育时期干旱监测效果评价——Ⅱ.改进的层次分析法和变异系数法组合赋权

运用改进的层次分析法、变异系数法及主客观组合赋权法确定关中平原冬小麦越冬后主要生育时期干旱对产量的影响权重,建立关中平原五市2002—2009年每年的加权条件植被温度指数(VTCI)与冬小麦单产的一元线性回归模型,分析VTCI与产量间的线性关系。结果表明,变异系数法确定的加权VTCI与小麦单产的线性相关性不显著,渭南、咸阳及铜川的决定系数R²值均低于0.5;改进的层次分析法和组合赋权法确定的加权VTCI与小麦单产的线性相关性显著,除铜川外其余四市的R²值接近0.5,或者高于0.6,且组合赋权法的结果中西安的R²值达到0.7。基于改进的层次分析法和变异系数法的归一组合赋权法的结果优于其它 主客观组合赋权法的结果,为最优赋权方法,可用于评价冬小麦主要生育时期的干旱监测效果。     

蕾期和花铃期不同灌水下限对滴灌棉花产量的影响

为探究棉花生长关键时期灌溉预警线,2017年在新疆呼图壁县开展了蕾期和花铃期灌水下限分别为55%（仅蕾期）、65%和75%田间持水量（θ_f）及其不同组合的大田试验,研究了不同滴灌条件下棉花的生长及产量状况。结果表明：灌水下限的提升对株高和生物量有明显的促进作用,在蕾期灌水下限从55%θ_f增至75θ_f,棉花株高和生物量分别增加了0.18~0.19 cm·d^-1和11.58~20.44 g;在花铃期灌水下限从65%θ_f增至75θ_f,棉花株高和生物量分别增加了0.04~0.10 cm·d^-1和3.47~4.04 g;蕾期和花铃期灌水下限分别为65%θ_f和75%θ_f时单铃重和单株成铃数分别为5.58 g和7.79个·株^-1,显著高于其他处理;蕾期和花铃期灌水下限均为75%θ_f时耗水量最大,为517.05 mm;蕾期和花铃期灌水下限分别为55%θ_f和65%θ_f时籽棉产量显著低于其他处理;蕾期和花铃期灌水下限分别为65%θ_f和75%θ_f时与均为75%θ_f时产量无显著性差异。综上,棉花蕾期和花铃期灌水下限分别为65%θ_f和75%θ_f为适宜的灌溉预警线。以播后天数为自变量,Logistic模型可以很好地模拟棉花的株高和生物量,以耗水量和株高为自变量预测棉花生物量变化情况的模型可为滴灌棉花灌水量及生长状况预测提供指导。     

2-取代苯基-5-取代苯甲酰胺基-1,3,4-噻二唑的合成、抑菌活性及三维定量构效关系

以取代苯甲酸为起始原料，与氨基硫脲、三氯氧磷及取代苯甲酰氯进行缩合，制备了33个2-取代苯基-5-取代苯甲酰胺基-1,3,4-噻二唑 E ₁ ~E ₃₃ 。采用核磁共振氢谱 (1H NMR) 和高分辨质谱 (HRMS) 等对目标化合物的结构进行了确证及表征。采用菌丝生长速率法测定了目标化合物对根霉Rhizopus nigricans、青霉Penicillium glaucum、灰霉Botrytis cinerea、交链孢霉Alternaria brassicae和黑曲霉Aspergillus niger的体外抑菌活性。针对黑曲霉的抑制活性，分别利用CoMFA和CoMSIA对目标化合物进行了初步的三维定量构效关系 (3D-QSAR) 研究。结果表明，大部分化合物表现出良好的抑菌活性，在50 μg/mL下，化合物 E ₁ 、 E ₂ 和 E ₂₉ 对供试真菌的抑制率均达到80%以上，与对照药剂百菌清和多菌灵的抑菌效果相当。综合两种模型的结果，发现静电场的贡献值高于其他势场，且当苯环a的4位引入供电子基、苯环a的2位和6位以及苯环b上引入吸电子基时，有利于化合物抑菌活性的提高，可为进一步指导设计合成此类高活性化合物提供理论依据。     

Ligand-based computer-aided pesticide design. A review of applications of the CoMFA and CoMSIA methodologies

An overview is given of the CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indices analysis) methodologies that are established ligand-based molecular design tools widely used by medicinal and pesticide chemists. In the absence of a three-dimensional structure of the target biopolymer, CoMFA and CoMSIA often provide a practical solution to an otherwise intractable problem of proper characterization of ligand-receptor interactions. These techniques are especially important in agrochemistry, where the number of known molecular structures of pesticide targets is limited. The use of CoMFA and CoMSIA in the agrochemical field for modelling the interactions of insecticides, fungicides, herbicides and herbicide safeners with their target binding sites is illustrated by using some selected published work. The CoMFA and CoMSIA models developed have been used successfully to map the properties of unknown receptors, construct hypotheses for ligand-receptor interactions, optimize lead structures, design novel active compounds, and predict biological activities. The application of CoMFA by the present authors for deriving a binding site hypothesis for dichloroacetamide-type herbicide safeners is described in somewhat more detail.     

噁唑烷类安全剂的三维定量构效关系研究

针对25个噁唑烷类化合物,以玉米根部GST活性为衡量标准,运用三维定量构效关系中的比较分子力场分析(CoMFA)和比较分子相似性指数分析(CoMSIA)两种方法进行研究;应用20个化合物作为训练集,分别建立相应的模型,并对其进行结构和活性关系的分析。CoMFA模型的交叉验证系数q2为0.647,非交叉验证系数r2为0.999;CoMSIA模型交叉验证系数q2为0.527,非交叉验证系数r2为0.949。使用训练集以外的5个化合物进行了验证,两种模型预测值与实测值偏差较小,都显示出了较好的预测性和稳定性。研究结果可为设计新的噁唑烷类潜在的除草剂安全剂提供可靠信息。     

Quantitative structure–activity studies of insect growth regulators xiv. Three-dimensional quantitative structure–activity relationship of ecdysone agonists including dibenzoylhydrazine analogs

N-tert-Butyl-N,N′-dibenzoylhydrazines such as tebufenozide (RH-5992) mimic the action of a molting hormone, 20-hydroxyecdysone, and cause premature molting of larvae leading to their death. Previously, it was shown that one of the benzoyl moieties in dibenzoylhydrazines plays a role similar to that of the aliphatic side chain at the C-17 position of ecdysones. In the present study, N-benzoyl-N′-benzylhydrazine, N,N′-dibenzylhydrazine, and N-alkanoyl-N′-benzoylhydrazine analogs have been synthesized to compare the effects of two carbonyl groups as well as two benzene rings of dibenzoylhydrazine. The quantitative structure–activity relationship of ecdysone agonists including dibenzoylhydrazine analogs was analyzed three-dimensionally using the CoMFA (comparative molecular field analysis) procedure. The CoMFA results suggested that the two carbonyl oxygen atoms of the diacylhydrazine skeleton probably correspond to the oxygens of the 20- and 22-OH groups of ecdysones, and that the benzoyl moiety located closer to the tert-butyl group is important for retaining high activity. © 1998 SCI     

Sites of Action of Noncompetitive GABA Antagonists in Houseflies and Rats: Three-Dimensional QSAR Analysis

Quantitative structure–activity relationships for insecticidal activity (against houseflies) and competitive activity against a specific [³⁵S]tert-butylbicyclophosphorothionate binding (to rat brain membranes) of some picrotoxinin-type 4-aminobutyric acid antagonists, including γ-BHC, endosulfan, bicyclophosphates, dioxatricyclododecenes and related compounds, were examined three-dimensionally using comparative molecular field analysis (CoMFA). The antagonists were classified into two series according to their molecular shapes: i.e. whether their structure was ‘linearly’ extended beyond the ‘mast-head’ position of the ‘boat-like’ skeletons (series 1) or not (series 2). The CoMFA showed that the slopes in steric and electrostatic fields around the molecule were significant for both series in governing the potency variations in insecticidal and binding activities. Hydrophobicity, a possible factor controlling transport behaviour of compounds, was significant in governing variations in insecticidal activity, but not for the case of the rat membrane binding. Assuming that there is a slight topological difference between series 1 and 2 compounds in terms of the mode of binding with the housefly receptor site, the insecticidal activity was analysable with a single equation for the combined set of compounds, but the rat membrane binding was not. The sterically and electrostatically favourable regions surrounding the molecular series indicated by CoMFA were roughly located at positions so as to interact with the binding subsites on the receptors proposed previously. © of SCI.     

Three‐dimensional quantitative structure–activity relationship analysis of acyclic and cyclic chloronicotinyl insecticides

The binding activity of chloronicotinyl insecticides, including acetamiprid, nitenpyram and related compounds, to the nicotinic acetylcholine receptors (nAChR) of houseflies was measured. These compounds were defined as ‘acyclic’ compounds. Variations in the binding activity were analysed using comparative molecular field analysis (CoMFA) which is a technique for the analysis of three‐dimensional quantitative structure–activity relationships. The CoMFA results showed that steric interactions were more significant for the acyclic compounds than for imidacloprid and its derivatives (cyclic compounds). It was also shown that the acyclic compounds could bind to housefly‐nAChR in a similar manner to the cyclic compounds, and that the electrostatic natures of the acyclic amino‐ and cyclic imdazolidine‐moieties affected their binding activity. © 2000 Society of Chemical Industry     

新型含噻唑和三唑环的亚胺类杀菌剂的QSAR研究

应用Cerius2软件中的主成分分析法(PCA)和Var.Jarvis-Patrick聚类方法对新型含噻唑和三唑环的亚胺类杂环化合物进行分类,再用遗传函数算法(GFA)和分子力场分析方法(MFA)分别进行了二维/三维定量构效关系研究(QSAR),所建模型都通过了显著性检验,CV-r2均大于 0.910,表明模型都具有良好的预测可靠性。计算研究表明:分子的热力学性质(各种原子类型AlogP描述符)、空间结构状态(Jurs参数和Shadow参数)和电拓扑状态指数(S_aaCH)是影响活性的主要二维因素。三维研究结果表明,分子的静电作用强弱对活性影响较大。最后根据药物分子设计理论设计了一系列亚胺类化合物,并用所建最优二维/三维QSAR模型进行活性预测与相互验证,筛选出活性可能较高的6个化合物。该研究可为高效亚胺类杀菌剂的研制提供理论指导。     

QSAR and 3D-QSAR analysis of structurally diverse ALS inhibitors: sulfonylureas and triazolopyrimidine-2-sulfonamides

For the purpose of better understanding the molecular mechanism of action of sulfonylurea and sulfonamide herbicides, the quantitative relationship between their structure and herbicidal activity against rape, Brassica campestris L, was analysed using physicochemical parameters and regression analysis and comparative molecular field analysis (CoMFA). The results showed that the structure–activity relationships of the two sets of compounds were identical, which suggested that the two different sets of compounds affect a common region of the receptor site. The CoMFA results were consistent with those derived from traditional QSAR analysis. Combining the traditional QSAR analysis with the CoMFA results, we can conclude that the variations in the herbicidal activity of the two sets of ALS inhibitors were governed dominantly by the three-dimensional steric and electrostatic field parameters of molecules participating in the interaction with the receptor site and there is apparently an optimum electronic property (Σσ or pKa) for the molecules to fit the receptor. © 1999 Society of Chemical Industry     

Design, synthesis, insecticidal activity and structure-activity relationship of 3,3-dichloro-2-propenyloxy-containing phthalic acid diamide structures

BACKGROUND: Phthalic acid diamide derivatives are among the most important classes of synthetic insecticides. In this study, a 3,3‐dichloro‐2‐propenyloxy group, the essential active group of pyridalyl derivatives, was incorporated into phthalic acid diamide derivatives with the aim of combining the active groups to generate more potent insecticides. RESULTS: Thirty‐one new phthalic acid diamides were obtained, and these were characterised by ¹H and ¹³C NMR. The structure of N²‐[1,1‐dimethyl‐2‐(methoxy)ethyl]‐3‐iodo‐N¹‐[4‐(3,3‐dichloro‐2‐propenyloxy)‐3‐(trifluoromethyl)phenyl]‐1,2‐benzenedicarboxamide was determined by X‐ray diffraction crystallography. The insecticidal activities of the compounds against Plutella xylostella were evaluated. The title compounds exhibited excellent larvicidal activities against P. xylostella. Structure‐activity relationships revealed that varying the combination of aliphatic amide and aromatic amide moieties, or the nature and position of substituent Y on the aniline ring, could aid the design of structures with superior performance. CONCLUSION: A series of novel phthalic acid diamides containing a 3,3‐dichloro‐2‐propenyloxy group at the 4‐position of the aniline ring were designed and synthesised. Structure‐activity relationships with the parent structure provided information that could direct further investigation on structure modification. Copyright © 2012 Society of Chemical Industry     

Design, semisynthesis and insecticidal activity of novel podophyllotoxin derivatives against Brontispa longissima in vivo

In an attempt to find the effective phytopesticides, a series of novel podophyllotoxin derivatives were firstly synthesized and preliminarily tested for their antifeedant and insecticidal effects against the fifth-instar larvae of Brontispa longissima. The different antifeedant and insecticidal activity ranges of compounds 3a-l showed that variations of NR₁R₂ groups in the 4-position of podophyllotoxin skeleton markedly affected the activity profiles of this compound class, and some important SAR information has been revealed from it. To clarify their mode of action of insecticidal activity, the docking models as well as tubulin inhibitory effect of representative compound 3i were also investigated, and the result indicated that the insecticidal activity of these compounds was due to the tubulin inhibitory effect of these derivatives, thereby possibly providing some useful information for rational designs of novel podophyllotoxin-based insecticides.     

Design, synthesis and insecticidal activities of novel pyrazole amides containing hydrazone substructures

BACKGROUND: Pyrazole and hydrazone derivatives possess good insecticidal activities; their substructural units are widely used in pesticide design. In an effort to discover new molecules with good insecticidal activities, a series of pyrazole amide derivatives containing hydrazone substructures were synthesised and bioassayed. RESULTS: Bioassays demonstrated that some of the title compounds exhibited notable control of Plutella xylostella (Linnaeus), Helicoverpa armigera (Hübner), Culex pipiens pallens, Laphygma exigua (Hübner), Spodoptera litura (Fabricius), Nilaparvata lugens (Stål) and Rhopalosiphum maidis (Fitch) at 5, 10, 0.25, 200, 20, 100 and 500 mg L^?1 respectively. Comparative molecular field analysis (CoMFA) based on the bioactivities for P. xylostella was studied; the values of q² and r² for the CoMFA model were 0.701 and 0.964 respectively. CONCLUSION: Some of the title compounds displayed good and broad‐spectrum insecticidal activities against different insect species; the CoMFA model revealed that a bulky and negatively charged group at the 4‐position of benzene could enhance insecticidal activity. These results could provide useful information for the design of novel insecticide containing substructural units of pyrazole amide and hydrazone. Copyright © 2011 Society of Chemical Industry