Acidic derivatives of the fungicide fenpiclonil: effect of adding a methyl group to the N-substituted chain on systemicity and fungicidal activity

A new acidic derivative of the fungicide fenpiclonil was synthesized containing a methyl group on the alpha-position of the carboxyl function of N-carboxymethyl-3-cyano-4-(2,3-dichlorophenyl)pyrrole. The phloem mobility of the resulting N-(1-carboxyethyl)-3-cyano-4-(2,3-dichlorophenyl)pyrrole was comparable with that of the former compound, but was higher at external pH 5.0. Unlike the derivatives previously synthesized, it was comparable with fenpiclonil in its fungicidal activity against the pathogenic fungus Eutypa lata.     

吩嗪-1-羧酸双酰肼衍生物的合成、杀菌活性及韧皮部的输导性研究

天然产物吩嗪-1-羧酸（PCA,申嗪霉素）及其衍生物吩嗪-1-甲酰肼具有独特的化学结构和优良的杀菌等生物活性,但均没有韧皮部输导性。本文以具有抑菌活性的吩嗪-1-羧酸和具有韧皮部输导性的马来酰肼为先导化合物,将马来酰肼中的双酰肼结构引入到吩嗪-1-羧酸中,设计、合成了17个新化合物,其结构均经过核磁共振氢谱、高分辨质谱及X-射线单晶衍射分析确证。初步生物活性测试表明:大部分目标化合物在50 mg/L下对水稻纹枯病菌Thanatephorus cucumeris表现出中等偏上的抑制活性,其中化合物6m的抑制率达92%。但输导性研究结果显示,目标化合物没有明显的韧皮部输导性。     

氟虫腈衍生物-糖基偶合物的合成及其在蓖麻韧皮部的输导性研究

为提高氟虫腈在植物体内的输导性,利用葡萄糖、半乳糖与木糖作为导向基团对其进行了糖基化修饰,设计合成了3个含乙酰保护基的糖基-氟虫腈偶合物(a,b,c)和3个脱保护基的偶合物(d,e,f)。采用液相色谱法测定了其在蓖麻幼苗韧皮部中的输导积累性。结果表明:化合物a、b、c无韧皮部输导性,而d、e、f 则具有良好的韧皮部输导性;培养2 h后,收集的第3 h内韧皮部液中 d、e、f 的浓度分别为21.45、14.14 和14.82 μ mol/L。饲料拌毒法测定结果表明,与母体化合物氟虫腈(LC50为4.49 μ mol/L)相比,6个偶合物对亚洲玉米螟Ostrinia furnacalis的杀虫活性均有所下降,LC50值在47.54~78.00 μ mol/L之间。     

Interference of the phenylpyrrole fungicide fenpiclonil with membranes and membrane function

The phenylpyrrole fungicide fenpiclonil accumulates to high levels in mycelium of Fusarium sulphureum and artificial liposomes. The accumulation is a result of a physicochemical distribution of the fungicide over lipid-like material of the mycelium and the medium. Accumulation is reversible, as the fungicide can easily be removed from the mycelium by washing with water. Fenpiclonil is not metabolized by the fungus during incubation for 24 h. The fungicide affects neither membrane fluidity in artificial liposomes nor amino acid accumulation in bacterial vesicles. Thus, accumulation of the fungicide does not seem to affect the functioning of membranes. Fenpiclonil induces the accumulation of the membrane-potential probe tetra-phenylphosphonium bromide by F. sulphureum. Since accumulation of this probe probably reflects the cumulative potential over all cell membranes, the increased accumulation is more likely a result of changes of potentials over membranes of intracellular organelles rather than plasma membrane hyperpolarization. Hence, the previously described effects of fenpiclonil on amino acid and saccharide uptake cannot be explained by plasma membrane hyperpolarization.     

The effect of dose and mobility on the strength of selection for DMI fungicide resistance in inoculated field experiments

Plots of spring wheat cv. Baldus were inoculated at GS 13 with four Mycosphaerella graminicola isolates, two relatively susceptible and two relatively resistant to DMI fungicides. Changes in the ratio of relatively susceptible to resistant types following fungicide or water sprays were measured. Three fungicides were compared: flutriafol, which is very mobile within leaves, fluquinconazole, which is less so, and prochloraz, which is almost immobile. All are inhibitors of sterol demethylation. In 1996, fungicide-treated plots were sprayed once with half the recommended dose at GS 39–47. In 1997, three doses were used: one-quarter and one-eighth of the recommended dose and a dual application of two one-eighth recommended doses, a week apart. Isolates were classified using a discriminating dose assay and the ratio of relatively susceptible to relatively resistant isolates in each field plot before and after fungicide application calculated. In both years, the numbers of relatively susceptible and relatively resistant isolates were equal just before fungicide application. All fungicides caused significant selection towards resistance, but the strength of selection varied with fungicide, dose and position in the crop canopy. Fluquinconazole selected most strongly and gave the best control of disease. Interactions between fungicide and dose were not significant. Selection was equally strong all along leaves sprayed with prochloraz, but increased smoothly from base to tip of leaves sprayed with fluquinconazole or flutriafol. Averaged over fungicides, reducing the dose of a single fungicide application from one-quarter to one-eighth slightly reduced selection towards resistance on both leaf layers. The dual one-eighth dose caused twice the change of the single one-eighth dose on the flag leaf, but was similar to a single spray on leaf 2.     

1-异丙基-3-酰基-5-甲氧基苯并咪唑酮衍生物的合成及抑菌活性

以4-甲氧基-2-硝基苯胺（1）为起始原料,经烷基化、硝基还原和环化反应制得中间体1-异丙基-5-甲氧基苯并咪唑酮（4）,再经N-酰化反应得到24个1-异丙基-3-酰基-5-甲氧基苯并咪唑酮衍生物（5a~5x）,通过核磁共振氢谱及元素分析对其结构进行了表征。初步抑菌活性测定结果表明,所有目标化合物对番茄灰霉病菌Botrytis cinerea的孢子萌发均有不同程度的抑制作用,其中5i（2-乙基丁酰基衍生物）和5q（2-甲基苯甲酰基衍生物）活性最高,在50 μg/mL时的抑制率分别为95.9%和93.4%。     

曲酸及氯曲酸衍生物的合成及抑菌活性

以曲酸为原料,设计合成了16个曲酸衍生物(QI-01~QI-16)和10个氯曲酸衍生物(QII-01~QII-10),通过核磁共振氢谱及元素分析对其结构进行了表征。初步抑菌活性测定结果表明:所有供试化合物对苹果炭疽病菌Glomerella cingulata和番茄灰霉病菌Botrytis cinerea的菌丝生长均有不同程度的抑制作用,其中化合物QI-07和QI-11对苹果炭疽病菌活性最高,50μg/mL时的抑制率分别为79.3%和86.2%;化合物QII-04、QII-08和QII-09对番茄灰霉病菌活性最高,50μg/mL时的抑制率分别为70.0%、70.0%和76.7%。     

Fungicidal activity of N-(2-cyano-2-methoximinoacetyl)amino acids and their derivatives

More than 20 N-(2-cyano-2-methoximinoacetyl)amino acids and derivatives were synthesised and tested for antifungal activity against grape downy mildew, caused by Plasmopara viticola (de Bary) Berl. & de Toni, and rape downy mildew, Peronospora parasitica Fr. Two of the compounds containing a free carboxylic acid group, a moiety which has been shown to confer phloem mobility on compounds, showed high activity, especially against P. parasitica, in protectant tests. These results indicate that there is no incompatibility between the acid function and fungicidal activity. A number of the esters showed activity comparable with that of cymoxanil in the protectant tests, and the tert-butyl esters of the methionine derivative and its sulfone were more than ten times as active as the commercial compound.     

6,7-亚甲二氧基硫代苯并二氢吡喃-4-酮衍生物的合成及抑菌活性

以亚甲二氧基苯为起始原料,经过溴化、硫化、环化等反应合成了19个未见文献报道的6,7-亚甲二氧基硫代苯并二氢吡喃-4-酮衍生物,其结构均经核磁共振氢谱和质谱确认。初步抑菌活性测试结果表明,在50 mg/L下,目标化合物对供试7种植物病原菌均有不同程度的抑制作用,其中化合物5b、5i、5k和5l对马铃薯干腐病菌 Fusarium solani的抑制率均达75%以上,5h和5i对番茄灰霉病菌Botrytis cinerea的抑制率分别是67.7%和70.4%。     

万寿菊杀菌素Ⅰ抗菌性及其对西瓜枯萎病菌作用机理的初步研究

西瓜枯萎病又称萎蔫病或蔓割病,是一种世界性瓜类土传病害。自1894年在美国南卡罗来纳州首次发现以来,目前几乎发生于世界各个西瓜产区,严重威胁着西瓜的安全生产,是西瓜的主要病害之一[1]。近几年来,由于西瓜种植面积不断扩大,造成轮作困难,致使枯萎病的危害也逐年加     

橙酮类似物的合成及抑菌活性

以芝麻酚和芳香醛为主要原料,经傅-克酰基化、关环和羟醛缩合反应,设计合成了14个未见文献报道的橙酮类似物,其结构均经1H NMR、MS和IR确证。初步抑菌活性测定结果表明:在100 mg/L下,所有目标化合物对7种供试病原菌均有不同程度的抑制作用,其中化合物 3a、3b、3c和3d 对番茄灰霉病菌Botrytis cirerea的抑制率达到100%, 3g 对小麦赤霉病菌Fusarium graminearum、玉米弯孢叶斑病菌Curvulavia lunata、棉花枯萎病菌Fusarium oxysporum vasinfectum、水稻稻瘟病菌Magnaporthe grisea的抑制率均大于80%, 3m 对马铃薯干腐病菌Fusarium solani和玉米弯孢叶斑病菌的抑制率分别为100%和83.8%。     

Synthesis of D-glucosamine quaternary ammonium derivatives and evaluation of their antifungal activity together with aminodeoxyglucose derivatives against two wood fungi Coriolus versicolor and Poria placenta: structure-activity relationships

BACKGROUND: Structure–activity relationships are often reported in scientific studies. These may be employed in searching for new acceptable biocides to use against harmful microorganisms, because the biocides used hitherto encounter various problems, including lack of efficiency, high toxicity and persistence. Nowadays, scientists are trying to find new, environmentally acceptable biocides to replace these earlier biocides. Different compounds from renewable materials have been studied and have shown pronounced antifungal activity against wood fungi. These include aminopolysaccharide derivatives and different quaternary ammonium polymers. A biological study carried out with these products indicated a possible relationship between amino groups and differences in biological activity observed. RESULTS: In this study, an amino group was successively fixed to different carbon atoms of glucose, and glucosamine was also modified by both N‐alkylation and quaternisation. The impact of the amino group position on antifungal activity against two wood decay fungi was investigated. The amino group at the anomeric position showed the highest antifungal activity against both Coriolus versicolor Quel. and Poria placenta (Fr.) Cooke. Furthermore, the positive impact of both N‐alkylation and quaternisation on the growth of both strains was demonstrated. CONCLUSION: The anomeric position of the amino group and the N‐alkylation and quaternisation of amino sugars considerably increase the antifungal activity of these compounds. Copyright © 2010 Society of Chemical Industry     

1-甲基-3-二氟甲基吡唑酰胺类化合物的合成及抑菌活性

以1-甲基-3-二氟甲基吡唑-4-甲酸为原料,经过1-甲基-3-二氟甲基吡唑-4-甲酰氯与相应的氨基苯并杂环类、芳胺类化合物反应,得到了14个未见文献报道的吡唑-4-甲酰胺类化合物(6a~6g、7a~7g),其结构均通过1H NMR、MS和IR表征。抑菌活性测试结果表明,在100 mg/L下,目标化合物对供试植物病原菌均有不同程度的抑制作用,其中7a~7g的抑菌活性较高,部分对苹果炭疽病菌的抑制率在90%以上。     

3-取代苯亚甲基-6,7-亚甲二氧基-4-色满酮的合成及抑菌活性

以芝麻酚为起始原料,经过醚化、傅克酰基化、羟醛缩合等反应,设计合成了21个未见文献报道的6,7-亚甲二氧基-4-色满酮类化合物（d1~d21）,其结构均经核磁共振氢谱、碳谱以及红外光谱和质谱确认。初步抑菌活性测定结果表明:在50 mg/L下,中间体色满酮及所有目标化合物对8种供试植物病原菌均有不同程度的抑制作用,其中色满酮对番茄灰霉病菌Botrytis cinerea和烟草赤星病菌Alteraria alternate的抑制率分别为87.9%和56.7%,目标化合物d1和d6对水稻稻瘟病菌Mangnaporthe grisea的抑制率分别为72.2%和52.5%,d6对玉米弯胞病菌Curvulavia lunata和d9对苹果腐烂病菌Valsa mali的抑制率均在70%以上。