共查询到20条相似文献，搜索用时 500 毫秒
1.
Attila E. Pavlath 《Pest management science》1986,17(4):412-417
A fluorine atom attached to an aromatic or heterocyclic system is quite stable in many chemical and biochemical reactions. Its size, in contrast to other halogen atoms, is comparable to that of a hydrogen atom and therefore, fluorine substitution does not distort the steric configuration of most compounds involved in biological processes. This can result in the incorporation of fluorinated compounds at some stage into the life cycle of various organisms. The high electronegativity of the fluorine, however, may alter considerably the reaction kinetics and mechanism of such intermediates at a later stage of the cycle causing biological disruption and possible pesticidal effect. 相似文献
2.
Peter Jeschke 《Pest management science》2010,66(1):10-27
The past 30 years have witnessed a period of significant expansion in the use of halogenated compounds in the field of agrochemical research and development. The introduction of halogens into active ingredients has become an important concept in the quest for a modern agrochemical with optimal efficacy, environmental safety, user friendliness and economic viability. Outstanding progress has been made, especially in synthetic methods for particular halogen‐substituted key intermediates that were previously prohibitively expensive. Interestingly, there has been a rise in the number of commercial products containing ‘mixed’ halogens, e.g. one or more fluorine, chlorine, bromine or iodine atoms in addition to one or more further halogen atoms. Extrapolation of the current trend indicates that a definite growth is to be expected in fluorine‐substituted agrochemicals throughout the twenty‐first century. A number of these recently developed agrochemical candidates containing halogen substituents represent novel classes of chemical compounds with new modes of action. However, the complex structure–activity relationships associated with biologically active molecules mean that the introduction of halogens can lead to either an increase or a decrease in the efficacy of a compound, depending on its changed mode of action, physicochemical properties, target interaction or metabolic susceptibility and transformation. In spite of modern design concepts, it is still difficult to predict the sites in a molecule at which halogen substitution will result in optimal desired effects. This review describes comprehensively the successful utilisation of halogens and their unique role in the design of modern agrochemicals, exemplified by various commercial products from Bayer CropScience coming from different agrochemical areas. Copyright © 2009 Society of Chemical Industry 相似文献
3.
A series of compounds containing fluorine atoms in place of hydrogen in olefinic non-ester pyrethroids has been synthesised using a route based on novel intermediates, ie 2-fluoroallyl acetates, which are coupled with aryl Grignard reagents, and tested against several insect species. In most cases, after introduction of fluorine at the olefinic position, the activity remains high in both the 1-aryl-1-(3-arylprop-2-enyl)cyclopropane and the (1-aryl-4-arylbut-2-enyl)cyclopropane series. In particular, the former series have potential as soil insecticides, because in tests against Diabrotica balteata, activities were high, and dose-transferability factors were increased by the introduction of fluorine. © 1999 Society of Chemical Industry 相似文献
4.
付一峰 左翔 范志金 米娜 郑琴香 黄云 王唤 黄杰 BELSKAYA N.P. BAKULEV V.A. MORZHERIN Yu.Yu. PROKHOROVA P.E. 《农药学学报》2010,12(4):408-416
为了寻找更多高活性化合物和进行先导结构的衍生,利用Ugi反应设计合成了18个 4-甲基-1,2,3-噻二唑新化合物(I-1~I-18),其结构均经核磁共振氢谱、红外光谱和高分辨质谱的表征和确认。杀菌、抗病毒以及诱导活性的筛选结果表明:目标化合物I-3和I-11抗烟草花叶病毒(TMV)的半叶法活性高于对照药剂病毒唑,I-6的保护活性和钝化活性高于病毒唑,I-12的治疗活性高于病毒唑,I-16的诱导活性高于对照药剂噻酰菌胺;氟原子的引入有利于保持和提高新化合物的抗病毒活性,4-甲基-1,2,3-噻二唑和氟原子是新化合物抗病毒的重要活性亚结构单元。Ugi反应是新农药创制中先导优化的绿色手段。 相似文献
5.
6.
7.
Masamitsu Tsukamoto Tadashi Nakamura Hirohiko Kimura Hitoshi Nakayama 《Journal of Pesticide Science》2021,46(2):125
Herein, we provide a brief overview of the synthesis and applications of trifluoromethylpyridine (TFMP) and its derivatives in the agrochemical and pharmaceutical industries. Currently, the major use of TFMP derivatives is in the protection of crops from pests. Fluazifop-butyl was the first TFMP derivative introduced to the agrochemical market, and since then, more than 20 new TFMP-containing agrochemicals have acquired ISO common names. Several TFMP derivatives are also used in the pharmaceutical and veterinary industries; five pharmaceutical and two veterinary products containing the TFMP moiety have been granted market approval, and many candidates are currently undergoing clinical trials. The biological activities of TFMP derivatives are thought to be due to the combination of the unique physicochemical properties of the fluorine atom and the unique characteristics of the pyridine moiety. It is expected that many novel applications of TFMP will be discovered in the future. 相似文献
8.
Peter Jeschke 《Pest management science》2017,73(6):1053-1066
Agriculture is confronted with enormous challenges, from production of enough high‐quality food to water use, environmental impacts and issues combined with a continually growing world population. Modern agricultural chemistry has to support farmers by providing innovative agrichemicals, used in applied agriculture. In this context, the introduction of halogen atoms into an active ingredient is still an important tool to modulate the properties of new crop protection compounds. Since 2010, around 96% of the launched products (herbicides, fungicides, insecticides/acaricides and nematicides) contain halogen atoms. The launched nematicides contain the largest number of halogen atoms, followed by insecticides/acaricides, herbicides and fungicides. In this context, fungicides and herbicides contain in most cases fluorine atoms, whereas nematicides and insecticides contain in most cases ‘mixed’ halogen atoms, for example chlorine and fluorine. This review gives an overview of the latest generation of halogen‐containing pesticides launched over the past 6 years and describes current halogen‐containing development candidates. © 2017 Society of Chemical Industry 相似文献
9.
以内蒙古托克托县地区为研究对象,通过系统采集浅层地下水和土壤样品,分析研究区浅层地下水和土壤中氟化物的赋存分布规律及其相关性。结果表明:托克托县地区浅层地下水氟的最低浓度为0.15 mg·L~(-1),最高浓度为7.00 mg·L~(-1),平均值为2.10 mg·L~(-1)。研究区的绝大部分地区浅层地下水中氟含量大于1.00 mg·L~(-1),已不宜作为生活饮用水源。整体表现为东南部湖积台地地下水氟含量要高于西北部冲湖积平原地区。在低TH(总硬度)、偏碱性的浅层地下水环境中,Ca~(2+)的活度会降低,有利于F~-在地下水中的富集。浅层地下水中氟与土壤水溶性氟的空间浓度分布特征具有较高的相似性,湖积台地及蛮汉山前地带沉积的富氟矿物,是本区土壤和浅层地下水中氟化物的主要来源。 相似文献
10.
11.
12.
Robert D Clark 《Pest management science》2018,74(9):1992-2003
Pesticides must be effective to be commercially viable but they must also be reasonably safe for those who manufacture them, apply them, or consume the food they are used to produce. Animal testing is key to ensuring safety, but it comes late in the agrochemical development process, is expensive, and requires relatively large amounts of material. Surrogate assays used as in vitro models require less material and shift identification of potential mammalian toxicity back to earlier stages in development. Modern in silico methods are cost‐effective complements to such in vitro models that make it possible to predict mammalian metabolism, toxicity and exposure for a pesticide, crop residue or other metabolite before it has been synthesized. Their broader use could substantially reduce the amount of time and effort wasted in pesticide development. This contribution reviews the kind of in silico models that are currently available for vetting ideas about what to synthesize and how to focus development efforts; the limitations of those models; and the practical considerations that have slowed development in the area. Detailed discussions are provided of how bacterial mutagenicity, human cytochrome P450 (CYP) metabolism, and bioavailability in humans and rats can be predicted. © 2018 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. 相似文献
13.
Scott McN. Sieburth Charles N. Langevine David M. Dardaris 《Pest management science》1990,28(3):309-319
Silicon effectively substitutes for quaternary carbon in etofenpr ox-type insecticides; the resulting dimethyl-4-ethoxyphenyl-3-(4-fluoro-3-phenoxyphenyl)propylsilane is a broad-spectrum insecticide with extremely low toxicity to fish. Four regions of this new silane insecticide have been systematically altered. The methyl groups on silicon appear to be critical for activity. Replacement of the fluorine with hydrogen results in a substantial loss of activity. The aromatic rings of the phenoxyphenyl fragment are best tethered by oxygen or carbonyl, the methylene and nitrogen analogs being of very low toxicity to the test species. The activity ranking of the methylene and carbonyl tethers is opposite to that found for ester pyrethroids. The relationship of insecticidal activity to the aromatic substituent para to the silicon atom has been found to correlate with the molar refractivity of the substituent. Replacement of a tetra-substituted carbon atom with a silicon atom can simplify construction of test compounds and thus be advantageously used in the exploration of structure—activity relationships. A novel method for preparing allylbenzenes from aromatic aldehydes was also developed. 相似文献
14.
小麦条锈病药剂防治试验 总被引：2，自引：0，他引：2
1962年和1963年,分别在信阳和郑州进行三次田间药剂防治小麦条銹病試驗結果表明:在叶面防治效果方面,超过0.5％对氨基苯磺酸10％以上的有0.5％与0.3％“閩农五号”、氟化鈉600倍、1000倍、氟矽酸鈉600倍、1％氨基苯磺酸鈉、1％氨基苯磺酸鋅、1％氨基苯磺酸鎳、0.1％与0.2％氮化鎳、0.2％氟化鎳及0.2％醋酸鎳等12种;超过1—10％或基本上相等的有1％常州氟鋇、1％氨基苯磺酸铁、0.1％与0.2％硫酸鎳四种;其中药效較好而又无药害、比对照增产10—35％的有1％氨基苯磺酸鈉、0.5—1％常州氟鋇、0.3—0.5％“閩农五号”、0.5％氨基苯磺酸铁及0.5％对氨基苯磺酸等;药效尚好而药害輕微、比对照增产10—20％的有1％氨基苯磺酸铁盐、0.5％鋅盐、0.5％鎳盐、0.1％醋酸鎳及氟矽酸鈉600倍等。田間药剂防治的适当时期和次数,根据病情动态和噴药效果分析,在河南省中南部地区建議以小麦的孕穗初、孕穗末或抽穗初、揚花期三次噴药为最好,灌浆以后噴药一般不起作用,如早春气温较高,病情上升迅速,則可在拔节期加噴一次。 相似文献
15.
含4-正庚/正辛氧基苯基杂环化合物的设计、合成及生物活性 总被引：1，自引：0，他引：1
通过研究苯甲脒类抑制剂与酮醇酸还原异构酶(KARI)对接的结合模式,设计合成了一系列含正庚氧基及正辛氧基苯基的杂环化合物。用核磁共振氢谱、红外光谱、质谱及元素分析对26个目标产物(其中22个是新化合物)的结构进行了表征和确认。初步生物活性测试结果表明,目标化合物大多具有不同程度的水稻KARI酶抑制活性和除草活性,其中化合物 9a和9b 在200 μg/mL浓度下对KARI酶的抑制率分别为65.7%和71.1%,在100 μg/mL浓度下对双子叶植物油菜Brassica campestris的抑制率分别达78.6%和89.0%。 相似文献
16.
Klaus Naumann 《Pest management science》2000,56(1):3-21
A number of well known polychlorinated chemicals are toxicologically and environmentally unsafe. Because of their persistence they are in the focus of public discussions against chlorine chemistry. However, chlorinated organic chemicals in the molecular weight range between 200 and 600 constitute an important and indispensable segment in the arsenal of existing biologically active chemicals used as pharmaceuticals or crop‐protection agents. Over the course of time it has been found empirically that the introduction of a chlorine atom into one or more specific positions of a biologically active molecule may substantially improve the intrinsic biological activity. In some cases the presence of a chlorine atom is crucial for significant activity in compounds derived both from nature and chemical synthesis. But in other cases chlorination diminishes or abolishes biological activity, as shown for chlordane homologues. Thus a chlorine atom, like any other substituent, is a modulator of activity. Almost all non‐reactive chlorinated chemicals and chlorine‐free chemicals are devoid of any biological activity at the highest concentration typically used in primary screening tests for discovery of useful biological properties. The influence of a substituent such as chlorine on the biological activity of a potential drug or crop protection agent still has to be established empirically in biological experiments designed to detect desired activity or toxicological properties. Sometimes chlorine does prove to be the optimum for improvement of activity. Long‐term rigorous investigations of several hundred chlorinated compounds, registered by the authorities as pharmaceutical drugs or crop‐protection agents, show that the generalisation ‘all chlorinated chemicals are dangerous’, deduced from the negative toxicological properties of a hundred chlorinated and reactive compounds of low molecular weight that are relevant in terms of safe working conditions in the chemical industry and for ecological safety, is not justified. Chlorinated compounds are not necessarily toxic or dangerous. Highly reactive chemicals or polychlorinated compounds cannot be compared with regard to toxicological properties with unreactive compounds having a low degree of chlorination. The chlorine atom, as one of many possible substituents used in synthetic organic chemistry, will remain in the future one of the important tools for probing structure–activity relationships in life science research and as a molecular component in commercialised compounds, in order to provide safer, more selective and more environmentally compatible products with higher activity for medicine and agriculture. © 1999 WILEY‐VCH Verlag GmbH 相似文献
17.
Tetsu Ando Nozomu Koseki Isamu Yasuhara Kie Kasuga Noritada Matsuo Takao Ishiwatari 《Pest management science》1994,40(4):307-312
The insecticidal activity of several new fluorinated pyrethroids was measured using houseflies untreated and treated with piperonyl butoxide (PB). 10, 10-Difluorophenothrin and 10, 10-difluoroallethrin, which include fluorine atoms at a position most easily attacked by mixed function oxidases (mfo) in the acid moiety, showed smaller topical LD50 values on the PB-untreated flies than the parent insecticides but rather large values on the PB-treated flies, suggesting that the introduction of fluorine prevents metabolic oxidation, although it has a negative effect on the interaction with a target site. Monofluorinated analogues of phenothrin, in which the structure of chrysanthemic acid was rearranged, still had moderate insecticidal activity, but flies were scarcely killed by 7 fluoroallethrin into which fluorine was introduced at a position most easily oxidized by mfo in the alcohol moiety. Competitive oxidation of the fluorinated derivatives and the parent compounds showed that fluorine at both the 10- and 7′-positions stabilizes the alkenyl side-chains of the pyrethroids against selenium dioxide and m-chloroperoxybenzoic acid. Photochemical studies with 10, 10-difluorophenothrin indicated that the photo-instability of the cyclopropanecarboxylic part could not be improved by this modification. 相似文献
18.
山西枣黑顶病致病因素分析 总被引：3，自引：0，他引：3
为了探明枣黑顶病的致病因素,在山西省晋中枣区选取5个有代表性的枣园,调查了枣黑顶病发病规律,对病果上的病原菌进行了分离与回接试验,测定了发病枣树的枣叶、枣果氟含量及大气的氟含量,并进行了氟化物浸果诱导黑顶病试验.结果表明:枣黑顶病的发病规律与普通侵染性病害不同;枣黑顶病在枣果膨大期、白熟期和成熟期均可发病,从黑顶病痛果中分离到6种真菌,对这些病原菌进行回接试验,均未诱导出与黑顶病相似的症状;枣黑顶病发病率与大气氟含量、枣叶片含氟量、枣果含氟量呈正相关关系;用氟化氢溶液也成功地诱导出枣黑顶病.说明氟污染是枣黑顶病的主要病因. 相似文献
19.
Strigolactones are a class of natural and synthetic compounds that in the past decade have been exciting the scientific community not only for their intriguing biological properties but also for their potential applications in agriculture. These applications range from their use as hormones to modify and/or manage plant architecture, to their use as stimulants to induce seed germination of parasitic weeds and thus control their infestation by a reduced seed bank, to their use as ‘biostimulants’ of plant root colonisation by arbuscular mycorrhizal fungi, improving plant nutritional capabilities, to other still unknown effects on microbial soil communities. More recently, these compounds have also been attracting the interest of agrochemical companies. In spite of their biological attractiveness, practical applications are still greatly hampered by the low product yields obtainable by plant root exudates, by the costs of their synthesis, by the lack of knowledge of their off‐target effects and by the not yet specified or properly identified legislation that could regulate the use of these compounds, depending on the agricultural purposes. The aim of this article is to discuss, in the light of current knowledge, the different scenarios that might play out in the near future with regard to the practical application of strigolactones. © 2016 Society of Chemical Industry 相似文献
20.
农药微乳剂浊点是微乳剂的主要质量技术指标之一。研究了3种不同种类农药的微乳剂组份与浊点的关系,并利用17O-核磁共振(17O-NMR)方法对其机理进行了探究。研究表明:浊点与表面活性剂、助表面活性剂与水之间形成的氢键强度成正相关;随着水质硬度的上升,浊点下降。建议选用亲水性强的表面活性剂和极性较强的助表面活性剂来配制微乳剂,同时为了节约成本和便于工厂生产,可采用自来水来配制农药微乳剂,而采取其他措施来提高农药微乳剂的浊点。 相似文献