4-取代-2-[(3-三氟甲基)-苯乙烯基]-1,3,4-噁二嗪-5-酮的合成及其生物活性

以3-(3-三氟甲基苯基)-丙烯酸为起始原料,设计并合成了14个4-取代-2-(3-三氟甲基)苯乙烯基-1,3,4-噁二嗪-5-酮衍生物,其化学结构经核磁共振氢谱及元素分析确证。初步的生物活性测定结果表明,该类化合物具有良好的杀虫活性,其中化合物 D-2,D-3,D-4,D-8 在质量浓度为50 mg/L时,对淡色库蚊Culex pipiens pallens的致死率分别为91.7% ,86.1% ,85.5%和93.9%。     

N-(7-氟-3-氧-3,4-二氢-苯并噁嗪-6-基-)乙酰胺类化合物的合成及除草活性

为了寻找高效、安全的具有除草活性的新化合物,利用2-取代乙酰氯和2H苯并噁嗪-3-酮反应合成了9个N-(7-氟-3-氧-3,4-二氢苯并噁嗪-6-基-)乙酰胺类化合物,其结构经元素分析、IR、1H NMR确证。初步除草活性测试表明:在有效剂量75 g/hm2下,化合物 5d 芽后茎叶处理对刺苋Amaranthus spinosus等4种杂草显示出90%以上的抑制率。     

N-(5-芳基-1,3,4-噁二唑-2-基)-N′-4-氟苯氧乙酰基硫脲的合成及抑菌活性

为了寻找更好的具有生物活性的化合物,从4-氟苯氧乙酸出发先合成酰基异硫氰酸酯,再与2-氨基-5-芳基-1,3,4-噁二唑反应合成了10个新的酰基硫脲类化合物,其结构经红外光谱、核磁共振氢谱、质谱和元素分析确认。采用平皿培养菌落生长速率法对6种病原菌进行了初步的生物活性测试,结果表明,在50mg/L浓度下,大部分化合物对黄瓜灰霉病菌Botrytis cinereapers、小麦赤霉病菌G ibberella zeae的抑制率达60%以上,其中Ⅱa、Ⅱc两个化合物对小麦赤霉病菌的抑制率达90%以上。     

N-(5-芳基-1,3,4-噁二唑-2-基)-N′-4-氟苯氧乙酰基硫脲的合成及抑菌活性

为了寻找更好的具有生物活性的化合物,从4-氟苯氧乙酸出发先合成酰基异硫氰酸酯,再与2-氨基-5-芳基-1,3,4-(噁)二唑反应合成了10个新的酰基硫脲类化合物,其结构经红外光谱、核磁共振氢谱、质谱和元素分析确认.采用平皿培养菌落生长速率法对6种病原菌进行了初步的生物活性测试,结果表明,在50 mg/L浓度下,大部分化合物对黄瓜灰霉病菌Botrytis cinereapers、小麦赤霉病菌Gibberella zeae的抑制率达60%以上,其中Ⅱa、Ⅱc两个化合物对小麦赤霉病菌的抑制率达90%以上.     

新型N-芳基-2-((5-((4,6-二甲基嘧啶-2-基)硫甲基)-1,3,4-噻二唑-2-基)硫)乙酰胺类化合物的合成及杀菌活性

为寻找新型杂环活性化合物,通过活性亚结构拼接,以硫脲和乙酰丙酮为起始原料合成4,6-二甲基嘧啶-2-硫醇,随后经酯化、肼化、环化和缩合反应,设计并采用微波辅助合成了10个新型N-芳基-2-（（5-（（4,6-二甲基嘧啶-2-基）硫甲基）-1,3,4-噻二唑-2-基）硫）乙酰胺类化合物,其结构通过核磁共振氢谱和碳谱、红外光谱、质谱及元素分析确认。初步生物活性测试结果表明,在50 mg/L下,大部分目标化合物对植物病原真菌具有一定的抑制活性,其中化合物8h对黄瓜炭疽病菌Colletotrichum orbiculare的抑制率达77.3%。     

N-(5-芳基-1,3,4-噁二唑-2-基)-N'-α-萘氧乙酰基硫脲的合成及生物活性

为了寻找更好的生物活性化合物,从α-萘氧乙酸出发合成酰基异硫氰酸酯,然后与2-氨基-5-芳基-1,3,4-噁二唑反应合成了10个新的酰基硫脲类化合物;其结构经红外光谱、核磁共振氢谱、质谱和元素分析确认。同时对6种病原菌进行了生物活性测试,结果表明,在50mg/L下,有6个化合物对水稻纹枯病菌抑制效果较好,抑制率达50%以上;特别是Ⅱ_e对苹果轮纹病菌抑制率达91.3%。     

2-(5,7-二甲基-1,2,4-三唑[1,5-a]嘧啶-2-硫代)乙酰胺类化合物的合成及除草活性

以芳胺或取代稠杂环胺、氯乙酰氯和2-巯基-5,7-二甲基-1,2,4-三唑 嘧啶为原料,合成了8个含稠杂环及芳环的三唑并嘧啶类新化合物,结构经1H NMR, MS 和IR确证,初步测定了该类化合物在室温下对稗草等3种禾本科杂草和反枝苋等3种阔叶杂草芽前芽后的抑制率,结果表明:有6个化合物在有效剂量75 g/hm2下的抑制率超过80%。     

吡啶衍生物研究(X):2-仲丁氨基-5-(2-芳氧吡啶 -4-基)-1,3,4-噻二唑的合成及除草活性

为了研究2-仲丁氨基-5-(2-氯吡啶-4-基)-1,3,4-噻二唑(BCPT)的结构-活性关系和开发活性更高的新型除草剂,以BCPT为先导化合物,依据活性亚结构连接法,在吡啶环2-位上引入二芳醚类除草剂的典型结构单元——芳醚,设计并合成了一系列新的芳氧吡啶噻二唑类化合物,其结构经元素分析和1H NMR确证。初步除草活性测定结果表明,在500 mg/L剂量下,所有化合物的除草活性(抑制率0~45%)远低于先导化合物(抑制率72％~87%),说明吡啶环2-位上的氯原子可能对维持该类化合物的除草活性是必需的。     

N-1,3,4-噁二唑基-N′-对溴苯氧乙酰基硫脲的合成及其抑菌活性

从对溴苯氧乙酸出发,先合成中间体酰基异硫氰酸酯,该中间体与2-氨基-5-芳基-1,3,4口-恶二唑反应合成了10个新的苯氧乙酰基硫脲类化合物,其结构经元素分析、红外光谱、核磁共振氢谱和质谱确认。初步生物活性测试结果表明,在50mg/L浓度下,所有目标化合物对水稻纹枯病菌Rhizatonia solani和黄瓜灰霉病菌Botrytis cinereapers的抑制率均达85%以上,部分化合物对黄瓜灰霉病菌的抑制率达100%。     

2-(5,7-二甲基-1,2,4-三唑[1,5-a]嘧啶-2-硫代)乙酰胺类化合物的合成及除草活性

以芳胺或取代稠杂环胺、氯乙酰氯和2-巯基-5,7-二甲基-1,2,4-三唑[1,5a-]嘧啶为原料,合成了8个含稠杂环及芳环的三唑并嘧啶类新化合物,结构经1H NMR,M S和IR确证,初步测定了该类化合物在室温下对稗草等3种禾本科杂草和反枝苋等3种阔叶杂草芽前芽后的抑制率,结果表明:有6个化合物在有效剂量75g/hm2下的抑制率超过80%。     

20-(S)-喜树碱7-C-取代衍生物的合成及杀松材线虫活性研究

为研究喜树碱(CPT)类化合物的杀线虫活性,以喜树碱为原料,经烷基化、氧化、酯化等步骤合成了13个7-C-取代的20-(S)-喜树碱衍生物,其中化合物 14 未见文献报道,所有衍生物的结构经红外光谱(FT-IR)、核磁共振氢谱(1H NMR)和液-质联用(LC-MS)等分析手段进行了表征。采用浸渍法测定了化合物对松材线虫Bursaphelenchus xylophilus的毒杀活性。结果表明:与母体化合物喜树碱相比,7-C-取代的20-(S)-喜树碱衍生物具有更强的杀线虫活性,其中化合物7-苄基喜树碱、7-甲酰基喜树碱、7-苯甲酰氧甲基喜树碱在24 h的致死中浓度(LC50值)分别为2.28、2.21和1.37 mg/L,明显高于母体化合物喜树碱的LC50值12.18 mg /L。     

The metabolism of p,p′-DDT by the feral pigeon (Columba livia)

Male feral pigeons were dosed with ring-labeled $\text{[}{}^{14}\text{C}\text{]p,p′-}\text{DDT}$ and the tissues and droppings analyzed for total ¹⁴C, extractable ¹⁴C, and metabolites. Only 16% of an intraperitoneal dose of 1.5–2.2 mg kg^?1 was voided in the droppings over 28 days; the rate of loss reached a maximum on the 14th day and then fell quickly away. The rate of removal of ¹⁴C in droppings was low in comparison to that found in the rat and the Japanese quail. When pigeons were dosed with 32–38 mg kg^?1 DDT per bird, and killed after 77 days, 5.4% of the dose was eliminated in droppings and 87% was recovered in the body. The tissues and droppings from this experiment were analyzed for DDT and its metabolites. Of the ¹⁴C remaining in tissues 88% was accounted for as the apolar compounds DDE, DDT, and DDD. Approximately half of the ¹⁴C in droppings was present as DDE, DDT, and DDD, whereas 27–35% was apparently in conjugated form, extractable from aqueous solutions by ethyl acetate after prolonged acid hydrolysis. Two polar metabolites were isolated from the acid-released material. One was p,p′-DDA; the other was extractable from aqueous solution at pH 8 and was tentatively identified as a monohydroxy derivative of p,p′-DDT. DDE accounted for 93% of the ¹⁴C present as metabolites in tissues and droppings, clearly indicating the importance of this intermediate in this study. The metabolism of DDT in the feral pigeon is discussed in relation to its metabolism by other species.     

Characterization of herbicidal injury by acifluorfen-methyl in excised cucumber (Cucumis sativus L.) cotyledons

Initial signs of herbicidal injury by several diphenyl ether herbicides were monitored by following the efflux of ⁸⁶Rb⁺ from treated cucumber (Cucumis sativis L.) cotyledons after exposure to light (600 μE m^?2 sec^?1; measured as PAR, i.e., photosynthetically active radiation between 400 and 700 nm). This very sensitive, rapid, and quantitative bioassay proved quite useful in (a) a structure-activity correlations study of the diphenyl ether compounds investigated and (b) an examination of herbicidal characteristics. The following diphenyl ether herbicides were analyzed: acifluorfen, sodium 5-[2-chloro-4-(trifluormethyl)phenoxy]-2-nitrobenzoate; acifluorfen-methyl (MC-10108), methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate; bifenox, methyl 5-(2,4-dichlorophenoxy)-2-nitrobenzoate; nitrofen, 2,4-dichlorophenyl p-nitrophenyl ether; nitrofluorfen, 2-chloro-1-(4-nitrophenoxy)-4-(trifluoromethyl)benzene; oxyfluorfen, 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene; MC-7783, potassium 5-(2,4-dichlorophenoxy)-2-nitrobenzoate; and MC-10982, ethyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate. Of the compounds investigated, acifluorfen-methyl (AFM) had the greatest degree of herbicidal activity. Cucumber cotyledons placed in high light (600 μE m^?2 sec^?1; PAR) with 10 nM AFM showed a significant increase in the efflux of ⁸⁶Rb⁺ within 2 to 4 hr. Light was required for herbicidal activity by AFM, and when treated cotyledons were returned to darkness, no further damage to the tissue occurred. By decreasing the quantity of light, the effect of the compound was delayed, although the magnitudes of the responses at the different intensities (600, 300, 150, and 75 μE m^?2 sec^?1; PAR) were nearly equal. By increasing the length of time of dark pretreatment with 1 μM AFM, ⁸⁶Rb⁺ efflux could be detected as early as 10 to 15 min after exposure to light (600 μE m^?2 sec^?1; PAR). Following light activation of AFM there was a simultaneous efflux of ⁸⁶Rb⁺, ³⁶Cl^?, ⁴⁵Ca²⁺, 3-O-methyl-[¹⁴C]glucose, and [¹⁴C]methylamine⁺. These data suggest the initial response to the herbicidal activity of AFM is expressed as a general increase in membrane permeability.     

N-[2-(4,6-二甲氧基嘧啶-2-氧基)苯亚甲基]取代胺类衍生物的合成及除草活性

以水杨醛为原料,经取代、加成和消除反应合成了6个标题化合物(3a~3f),其中4个(3a~3d)为新化合物,其结构经核磁共振氢谱、质谱和元素分析确认。初步的除草活性测试结果表明,在有效成分150 g/hm2的剂量下,除化合物3f对稗草Echinochloa crus-galli的抑制率为55%外,其余5个化合物对供试杂草的抑制率均在80%以上,部分化合物对稗草、早熟禾Poa annua、反枝苋Amaranthus retroflexus或小藜Chenopodium album的抑制率达100%。     

The antifeedant effect of some new withanolides on three insect species,spodoptera littoralis,epilachna varivestis andtribolium castaneum

The antifeedant effect of several new withanolides on larvae ofSpodoptera littoralis, Epilachna varivestis andTribolium castaneum was investigated. 2,3-Dihydrowithanolide E (II) was an antifeedant forS. littoralis andE. varivestis; nicalbin A (XIV), and a mixture of withanicandrin (IX) and daturalactone A (X), were active against E. varivestis andT. castaneum. Some activity was shown by 6β,14α,17β,20α_F-tetrahydroxy-1-oxowitha-2,4,24-trienolide (V) againstS. littoralis; 4β,5β-epoxy-6α,14α,17β,20α_F-tetrahydroxy-l-oxowitha-2,24-dienolide (VII) againstE. varivestis andT. castaneum; 5α,6α,-epoxy-14α,17β,20α_F-trihydroxy-1-oxowitha-2,24-dienolide (VI) againstE. varivestis; and nicalbin B (XV) againstT. castaneum.     

Development of a predictive uptake model to rationalise selection of polyoxyethylene surfactant adjuvants for foliage-applied agrochemicals

Composition-concentration relationships between a series of C₁₃/C₁₄ polyoxyethylene primary alcohol (AE) surfactants and the foliar uptake enhancement of five model neutral organic compounds were examined in factorially designed experiments on wheat (Triticum aestivum L.) and field bean (Vicia faba L.) plants grown under controlled environment conditions. Model compounds were applied to leaves as c.0.2-μl droplets of 0.5 g litre^?1 solutions in aqueous acetone in the absence or presence of surfactants at 0.2, 1 and 5g litre^?1. Uptake of the highly water-soluble compound, methylglucose (log octanol-water partition coefficient (P) = - 3.0) was best enhanced by surfactants with high E (ethylene oxide) contents (AE15, AE20), whereas those of the lipophilic compounds, WL110547 (log P = 3.5) and permethrin (log P = 6.5), were increased more by surfactants of lower E contents, especially AE6. However, there was little difference between AE6, AE11, AE15 and AE20 in their ability to promote uptake of the two model compounds of intermediate polarity, phenylurea (log P = 0.8) and cyanazine (log P = 2.1). Absolute amounts of compound uptake were also influenced strongly by both surfactant concentration and plant species. Greatest amounts of uptake enhancement were often observed at high surfactant concentration (5 g litre^?1) and on the waxy wheat leaves compared with the less waxy field bean leaves. The latter needed higher surfactant thresholds to produce significant improvements in uptake. Data from our experiments were used to construct a simple response surface model relating uptake enhancement to the E content of the surfactant added and to the physicochemical properties of the compound to be taken up. Qualitative predictions from this model might be useful in rationalising the design of agrochemical formulations.     

Eradication of over-wintering mildew (Podosphaera leucotricha) in apple buds by nitrogen-containing surfactants

The eradicant activities of 24 nitrogen-containing preparations, comprising primary, secondary or tertiary amines, amine acetates, diamines, amine oxides or quaternary ammonium salts, were assessed in trials with potted dormant apple rootstocks, heavily infected with the powdery mildew fungus Podosphaera leucotricha. The surfactants consisted of mixtures in which C₁₂/C₁₄ or C₁₆/C₁₈ alkyl or alkenyl compounds predominated. Of the amine acetates (at 50g litre^?1), only the formulation containing C₁₂/C₁₄ primary amine acctates was considered worthy of further evaluation. Some amine oxides and quaternary ammonium compounds (at 35 g litre^?1) were good eradicants and were as effective as ‘PP222’ a (nonylphenol-ethoxylate mixture) which was included for comparison. All the compounds showing good activity contained one C₁₂/C₁₄ alkyl group whereas C₁₆/C₁₈ compounds, whether saturated or unsaturated, were relatively inactive. In a field trial, C₁₂/C₁₄ (dimethyl) amine oxide, C₁₂/C₁₄bis (2-hydroxyethyl) amine oxide, and C₁₂/C₁₄ amine acetate (35 g litre^?1) greatly reduced the amount of primary mildew on trees that were previously heavily infected, but there were signs that the fruit yield was reduced.     

Withanolides and related ergostane-type steroids as antifeedants for larvae ofEpilachna varivestis (Coleoptera: Chrysomelidae)

Eight steroids isolated from solanaceous plants (Physalis, Withania andNicandra species) were investigated as to their antifeedant efficacy for L₄ larvae ofEpilachna varivestis Muls. (Coleoptera). Nicalbin A (VII) was a potent antifeedant, but at high concentrations it was also toxic to this insect. Other active compounds were withanolide E (I), 4β-hydroxywithanolide E (II), 5β, 6β-epoxy-1β, 14α, 17β, 20α-tetrahydroxywith-24-enolide (III), Nic-1 (nicandrenone, VI) and nicalbin B (VIII). These results were quite different from the spectrum of activity of the withanolides against larvae ofSpodoptera littoralis (Boisd.) (Lepidoptera) found in a previous study.     

The mechanism of fungistatic action of sec-butylamine: I. Effects of sec-butylamine on the metabolism of hyphae of Penicillium digitatum

Growth of Penicillium digitatum was inhibited after a 40-min incubation in a culture medium containing 0.5 mM sec-butylamine, and the dry weight of the hyphae was 50% of the control value after 180 min. Respiration of the hyphae was reduced 13% after a 20-min contact with 0.5 mM sec-butylamine but this treatment did not influence the uptake of amino acids, glucose, or phosphate nor intensify the efflux of ³³P- or ¹⁴C-labeled metabolites from the cells. The syntheses of cell walls and total lipids were inhibited 20–30% after a 90-min incubation with sec-butylamine, and nucleic acid synthesis was reduced to about 50% of the control value at this time. sec-Butylamine inhibited the incorporation of labeled carbon from [¹⁴C]glucose into the protein fraction of the hyphae to a greater degree than ¹⁴C derived from labeled proline, lysine, or leucine. These observations suggested that sec-butylamine interfered primarily with the intermediary metabolism of glucose rather than inhibiting a later stage of macromolecule synthesis. Hyphae incubated with [¹⁴C]glucose and sec-butylamine accumulated pyruvic acid to a level seven times greater than in control hyphae. Furthermore, sec-butylamine strongly inhibited ¹⁴CO₂ evolution from hyphae metabolizing [¹⁴C]pyruvate whereas CO₂ derived from acetate or glucose after a 45-min incubation was only slightly reduced by sec-butylamine. These observations implicate pyruvate oxidation as the primary site of sec-butylamine action in young hyphae of P. digitatum.     

Enhanced excretion of DDT and metabolites in rats treated with trans,trans-muconate

The interactions between trans,trans-muconate and p,p′-DDT were examined. Male Wistar rats were injected intraperitoneally with 6.67 mg kg^?1 [¹⁴C]p,p′-DDT. Two hours later the experimental animals received orally a solution of sodium muconate (75 mg kg^?1, 0.3 ml) in physiological saline, pH 7.2; control animals received an equal volume of physiological saline. Treatment was repeated every 12 hr for 10 days. Sodium muconate does not modify urinary excretion of labeled compounds, yet it reduces body burden by accelerating the excretion rate of these compounds in rat feces. This action was observed only during the first 24 hr after the animals were exposed to p,p′-DDT.