Synthesis and insecticidal activity of benzoheterocyclic analogues of N'-benzoyl-N-(tert-butyl)benzohydrazide: Part 2. Introduction of substituents on the benzene rings of the benzoheterocycle moiety

A series of N'-benzoheterocyclecarbonyl-N-tert-butyl-3,5-dimethylbenzohydrazide analogues possessing a variety of substituents on the benzene rings of the benzoheterocyle moieties were synthesized and tested for their insecticidal activity. The introduction of a methyl group at the R1 position of the benzoheterocycle moiety strongly increased the insecticidal activity. Among the analogues synthesized, N'-tert-butyl-N'-(3,5-dimethylbenzoyl)-5-methyl-6-chromanecarbohydrazide showed the highest insecticidal activity (LC50 = 0.89 mg litre(-1)).     

Synthesis and insecticidal activity of benzoheterocyclic analogues of N'-benzoyl-N-(tert-butyl)benzohydrazide: Part 1. Design of benzoheterocyclic analogues

The N'-benzoyl group of N-tert-butyl-N'-benzoyl-3,5-dimethylbenzohydrazide (1) was converted to a series of benzoheterocyclecarbonyl groups in order to investigate the potential usefulness of superimposing a hydrazine insecticide on 20-hydroxyecdysone. A series of analogues with benzodioxole, benzodioxane, benzodioxapine, indole, benzoxazole, benzoxazine or benzothiazole instead of the phenyl group of (1) were synthesized and tested for their insecticidal activity against the common cutworm (Spodoptera litura F). N-tert-Butyl-N'-(3,5-dimethylbenzoyl)-1,3-benzodioxole-5-carbohydrazide and N-tert-butyl-N'-(3,5-dimethylbenzoyl)-2,3-dihydro-1,4-benzodioxine-6-carbohydrazide showed high insecticidal activities, superior to that of (1) and equal to that of the commercial insecticide tebufenozide (RH-5992).     

Nicotinic acetylcholine receptor binding of imidacloprid-related diaza compounds with various ring sizes and their insecticidal activity against Musca domestica

Fifteen 5-substituted 1-(6-chloro-3-pyridylmethyl)-2-nitromethylene-1,3- diazacyclohexanes and three other related compounds having a five- or seven-membered ring were synthesized and their biological activities were measured in vivo and in vitro. The insecticidal (in vivo) activity was evaluated against houseflies Musca domestica L under synergistic conditions with propargyl propyl phenyl phosphonate and piperonyl butoxide. The binding activity of each compound to nicotinic acetylcholine receptor in vitro was measured using [125I] alpha-bungarotoxin. The insecticidal activities of the unsubstituted diazacyclohexane analogues were slightly higher than those of the imidazolidine analogues, but the enlargement of ring size to diazacycloheptane lowered the activity. Substitution of 1,3-diazacyclohexane or imidazolidine rings was not generally favourable for the activity, but the unsubstituted 1,3-diazacyclohexane analogue showed the highest binding activity. Ring substitutions and ring enlargement decreased the activity 100-30,000-fold.     

Lead optimization and anti-plant pathogenic fungi activities of daphneolone analogues from Stellera chamaejasme L.

In order to find the biorational pesticides, we have synthesized two series of daphneolone analogues including 5-methylfuryl chalcones and 5-nitrofuryl chalcones by optimizing daphneolone analogues from Stellera chamaejasme L. with the good insecticidal properties of Qinghai-Tibet Plateau. All the synthesized compounds have been evaluated for anti-plant pathogenic fungi activities. The bioactivity assay showed that some of these daphneolone analogues were potentially active against plant pathogenic fungi, Rhizoctonia solani, Gibberella zeae, Bipolaris maydis, Sclerotia sclerotium and Botrytis cirerea, while the most potent 1-(2,4-dichlorophenyl)-3-(5-methylfuran-2-yl)propenone (compound 7) in this study showed good inhibitory activity against R. solani at 200 mg L⁻¹ with ca. 100% inhibition.     

苦皮藤素类似物的合成与结构鉴定

以苦皮藤Celastrus angulatus Max.提取物水解产物中的多羟基β-二氢沉香呋喃为原料,合成了对粘虫Mythimna separata具有毒杀活性的苦皮藤素(Celangulin)类似物,并在活性追踪的指导下分离得到了两个具有杀虫活性的苦皮藤素类似物 A和B, 其结构经核磁共振谱、快原子轰击质谱、高分辨质谱等波谱学方法鉴定为2β,6α,8β,13-四异丁酰氧基-1β,4α,9α-三羟基-β-二氢沉香呋喃及1β,2β,6α,8β,13-五异丁酰氧基-4α,9α-二羟基-β-二氢沉香呋喃。化合物 A和B 均为新化合物,在20 mg/mL的浓度下对三龄粘虫Mythimna separata的胃毒活性(死亡率)分别为89.5%和93.2%。     

Insecticidal and binding activities of N3-substituted imidacloprid derivatives against the housefly Musca domestica and the alpha-bungarotoxin binding sites of nicotinic acetylcholine receptors

N3-substituted imidacloprid congeners containing C1-C6 alkyl groups or various analogous groups, and their corresponding nitromethylene analogues, were used in this study. Their insecticidal activity against the housefly, Musca domestica, and their binding activity toward the nicotinic acetylcholine receptor were determined. The insecticidal test was conducted using the synergists piperonyl butoxide and propargyl propyl phenylphosphonate. The binding assay was performed with housefly head membrane preparations using radio-labelled alpha-bungarotoxin. Both insecticidal and binding activities were drastically lowered by the introduction of alkyl/allyl groups at the imidazolidine NH sites of both nitroimino and nitromethylene compounds. The binding activity of N3-substituted nitromethylene analogues was much higher than that of the corresponding nitroimino analogues. However, the insecticidal activity of both series of compounds with a given substituent was nearly identical. The insecticidal activity correlated positively with the binding activity after taking into account the structural difference of the nitroimino and nitromethylene moieties and a structural feature of the N3-substituents.     

Binding activity of substituted benzyl derivatives of chloronicotinyl insecticides to housefly‐head membranes,and its relationship to insecticidal activity against the housefly Musca domestica

Variously substituted benzyl derivatives of chloronicotinyl insecticides were synthesized with a wide range of substituents including halogens, NO₂, CN, CF₃ and small alkyl and alkoxy groups at the ortho, meta and para positions, as well as multiple‐substituted benzyl analogues. Their binding activity to the α‐bungarotoxin binding site in housefly (Musca domestica) head membrane preparations was measured. Among the compounds tested, the activity of the meta‐CN derivative was the highest, being 20–100 times higher than those of imidacloprid, acetamiprid and nitenpyram. The synergized insecticidal activity against houseflies was also measured for selected compounds with the metabolic inhibitor, NIA16388 (propargyl propyl phenylphosphonate). For the nitromethylene analogues, including both benzyl and pyridylmethyl analogues, higher binding activity usually resulted in higher insecticidal activity. © 2000 Society of Chemical Industry     

Synthesis and insecticidal activity of novel 1,3,4-oxadiazolin-5-one and pyrazolin-5-one derivatives

A series of novel 2-(2,4,6-trisubstituted phenyl)-1,3,4-oxadiazolin-5-one derivatives and 3-(2,4,6-trichlorophenyl)pyrazolin-5-one derivatives were synthesized and evaluated for insecticidal activity. It was found that a moderately bulky alkyl group, such as a tert-butyl group, on the heterocyclic ring, and a trifluoromethyl group on the benzene ring were optimal substituents on the molecule. The oxygen atom in the oxadiazoline ring was essential for insecticidal activity. Of the compounds assayed, 4-tert-butyl-2-(2,6-dichloro-4-trifluoromethylphenyl)-1,3,4-oxadiazolin-5-one gave the highest activity against Nephtotettix cincticeps, with an LC₅₀ value of 0.51 mg litre⁻¹. © 1999 Society of Chemical Industry     

Insecticidal activity of deoxypodophyllotoxin, isolated from Juniperus sabina L, and related lignans against larvae of Pieris rapae L

In the course of screening for naturally occurring insecticides from plants from the northwestern part of China, a petroleum ether extract of Juniperus sabina L was found to show insecticidal activity against fifth-instar larvae of Pieris rapae L. From the extract, an insecticidal compound was isolated by bioassay-guided fractionation. The compound was identified as deoxypodophyllotoxin (1) by comparison of its spectroscopic characteristics with literature data. In bioassays, 1 showed antifeedant activity against fifth-instar larvae of P rapae at 0.05-1.00 g litre(-1) and its AFC50 (concentration for 50% antifeedant activity) values at 12 and 48h were 0.170 and 0.060 g litre(-1), respectively. In that concentration range, all treated insects died within 48 h after treatment and compound 1 showed delayed insecticidal activity. At 0.015-0.100 g litre(-1), 1 showed insecticidal activity, with an LC50 of 0.020 g litre(-1). The related compound deoxypicropodophyllotoxin (2), however, showed lower antifeedant and insecticidal activities than 1 in bioassay. This indicated that the trans-lactone ring is an important moiety for enhancing activity in these compounds. Comparison of the insecticidal activities of 1 and another related compound, podophyllotoxin (3), suggested that varying the substituent at C-4 is an exciting possibility for synthesizing more potent analogues.     

2-(溴代吡咯腈-1-基)乙酸衍生物的设计、合成及生物活性

为了发现具有生物活性的新化合物,以溴代吡咯腈为先导化合物,通过亲核取代等反应合成了一系列新型2-(溴代吡咯腈-1-基)乙酸衍生物(5a～5m, 6a～6o),其结构均经核磁共振氢谱(¹H NMR)、碳谱(¹³C NMR)和高分辨质谱(HRMS)确证。杀菌活性测定结果显示：化合物2、3和5m对水稻稻瘟病菌Magnaporthe oryzae均表现出良好的杀菌活性,其EC₅₀值分别为0.0532、0.0470和0.0174 mmol/L,优于对照药剂咯菌腈(0.0914 mmol/L),但不及对照药剂嘧菌酯(0.0001 mmol/L);化合物5m表现出一定的杀菌广谱性,其对水稻纹枯病菌Rhizoctonia solani和小麦根腐病菌Bipolaris sorokiniana的EC₅₀值分别为0.0218和0.0420 mmol/L,但均不及对照药剂咯菌腈(EC₅₀值分别为0.0002和0.0010 mmol/L)。杀虫、杀螨活性测定结果显示,在0.2 mmol/L浓度下,目标化...     

Insecticidal and fungicidal activity of new synthesized chitosan derivatives

Chitosan, the N-deacetylated derivative of chitin, is a potential biopolysaccharide owing to its specific structure and properties. In this paper, we report on the synthesis of 24 new chitosan derivatives, N-alkyl chitosans (NAC) and N-benzyl chitosans (NBC), that are soluble in dilute aqueous acetic acid. The different derivatives were synthesized by reductive amination and analyzed by 1H NMR spectroscopy. A high degree of substitution (DS) was obtained with N-(butyl)chitosan (DS 0.36) at a 1:1 mole ratio for NAC derivatives and N-(2,4-dichlorobenzyl)chitosan (DS 0.52) for NBC derivatives. Their insecticidal and fungicidal activities were tested against larvae of the cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), the grey mould Botrytis cinerea Pers (Leotiales: Sclerotiniaceae) and the rice leaf blast Pyricularia grisea Cavara (Teleomorph: Magnaporthe grisea (Hebert) Barr). The oral feeding bioassay indicated that all the derivatives had significant insecticidal activity at 5 g kg(-1) in artificial diet. The most active was N-(2-chloro-6-fluorobenzyl)chitosan, which caused 100% mortality at 0.625 g kg(-1), with an estimated LC50 of 0.32 g kg(-1). Treated larvae ceased feeding after 2-3 days; the mechanism of action remains unknown. In a radial hyphal growth bioassay with both plant pathogens, all derivatives showed a higher fungicidal action than chitosan. N-Dodecylchitosan, N-(p-isopropylbenzyl)chitosan and N-(2,6-dichlorobenzyl)chitosan were the most active against B cinerea, with EC50 values of 0.57, 0.57 and 0.52 g litre(-1), respectively. Against P grisea, N-(m-nitrobenzyl)chitosan was the most active, with 77% inhibition at 5 g litre(-1). The effect of different substitutions is discussed in relation to insecticidal and fungicidal activity.     

Synthesis and insecticidal properties of derivatives of propane-1, 3-dithiol (analogues of the insecticidal derivatives of dithiolane and trithiane from the alga Chara globularis Thuillier)

Functional derivatives of 2-(methylthio)propane-1, 3-dithiol (open chain analogues of the insecticidal 4-methyithio-1, 2-dithiolane and 5-methylthio-1, 2, 3-trithiane from the alga Chara globularis) possess insecticidal properties similar to those of the structurally related nereistoxin. Some derivatives of propane-1, 3-dithiol, bearing 2-substituents different from the methylthio group, have also been shown to have insecticidal pioperties.     

The discovery of pyridalyl: a novel insecticidal agent for controlling lepidopterous pests

Synthesis of analogues of two compounds with known insecticidal activity, both of which contain a 3,3-dichloro-2-propenyloxy group, produced 2-(trifluoromethyl)-4-phenoxyphenyl 3,3-dichloro-2-propenyl ether, which had weak activity against lepidopterous larvae. Structural modifications around this lead compound led to the development of pyridalyl [Pleo, S-1812; 2,6-dichloro-4-(3,3-dichloroallyloxy)phenyl 3-[5-(trifluoromethyl)-2-pyridyloxy]propyl ether], which belongs to a new class of insecticides. Pyridalyl gives very good control of various lepidopterous and thysanopterous pests on cotton and vegetables, without phytotoxicity. It controls populations of Heliothis virescens F and Plutella xylostella (L) which are resistant to various currently used insecticides. It also produces unique insecticidal symptoms, so it may have a different mode of action from other existing insecticides. Pyridalyl is also less harmful than existing insecticides to various beneficial arthropods, so it should provide an important tool in IPM and insecticidal management programmes for the control of lepidopterous and thysanopterous pests. The first market introduction is expected in Japan and some Asian countries in the years between 2004 and 2005.     

取代双吡唑类化合物的合成及杀虫活性

以3-氯苯肼盐酸盐( 1 )和1,1,3,3-四甲氧基丙烷( 2 )为起始原料,经环化、Vilsmeier反应得1-(3-氯苯基)-1H-吡唑-4-甲醛( 4);(4 )与3-三氟甲基苯乙酮( 5 )经Claisen-Schmidt缩合反应得取代芳基烯酮类化合物( 6 ),再与水合肼发生环化反应得3-(3-三氟甲基苯基)-5-(3-氯苯基-1H-吡唑)-4,5-二氢吡唑( 7),其与取代异氰酸酯 作用,制得15个未见文献报道的结构新颖的取代双吡唑类化合物。利用核磁共振氢谱(1H NMR)和质谱(MS)对其结构进行了表征。初步生物活性测定结果表明,在 500 mg/L 质量浓度下,部分化合物对小菜蛾Plutella xylostella的致死率达100%,而对苜蓿蚜Aphis medicaginis、稻褐飞虱Nilaparvata lugens、朱砂叶螨Tetranychus cinnabarinus均无杀虫活性。     

细交链孢菌酮酸及其衍生物的合成与杀虫活性

为了寻找具有较高杀虫活性的特胺酸化合物，以天然活性产物细交链孢菌酮酸(TeA)作为先导化合物，利用酰基化米氏酸作为酰基化试剂，设计、合成了26个3-位不同酰基取代和5-位不同取代的含特胺酸骨架衍生物 4a~4s、5a~5g、7a 和 8a ，其中14个化合物未见文献报道，所有目标化合物的结构均经核磁共振氢谱、碳谱和高分辨质谱确证。初步杀虫活性测定结果表明，在100 μg/mL下处理72 h内，所有目标化合物对麦长管蚜Macrosiphum avenae (Fabricius)均表现出良好的杀虫活性，并具有内吸性，其中化合物 5d 和 7a 48 h致死率为100%，高于对照药剂螺虫乙酯，具有作为先导化合物进一步研究的价值。对处理后的小麦植株进行残留量测定，结果表明目标化合物 4e、5c、7a 和 8a 能被植株较好的吸收 。 该研究结果可为进一步研究具有特胺酸骨架化合物的构效关系提供参考。     

新型吡唑双酰肼类化合物的合成及除草活性

为了寻找具有较高除草活性的农药先导化合物,将吡唑环与双酰肼结构进行拼接,设计合成了13个未见报道的含吡唑环的双酰肼类目标化合物6a~6m,其结构均通过核磁共振氢谱及高分辨质谱确认。培养皿法测定结果表明:在200 mg/L下,化合物N'-(2-(2,4-二氯苯氧基)乙酰基)-3-(二氟甲基)-1-甲基-1H-吡唑-4-甲酰肼(6i)对小麦Triticum aestivum、油菜Brassicacampestris、高粱Sorghum bicolor、萝卜Raphanus sativus和黄瓜Cucumis sativus根、茎的抑制率均达80%以上。盆栽试验表明:在有效成分150 g/hm2剂量下,采用苗后茎叶喷雾处理,化合物6i对反枝苋Amaranthus retroflexus和鳢肠Eclipta prostrata的抑制率均达80%;相同剂量下采用苗前土壤喷雾处理,6i对反枝苋A. retroflexus的抑制率也达80%。     

N-((5-烷硫基-1,3,4-噁二唑)-2-基)甲基溴代吡咯腈的合成及生物活性

为了发现农药活性的新化合物,以溴代吡咯腈为原料,通过亲核取代、肼解和成环等反应,设计合成了一系列N-((5-烷硫基-1,3,4-噁二唑)-2-基)甲基溴代吡咯腈目标化合物( 5a ~ 5t ),所有化合物的结构均得到核磁共振氢谱和高分辨质谱确证。杀菌活性测定结果显示:在浓度为0.20 mmol/L时,大部分目标化合物具有一定的抑菌活性,其中化合物 5h 对水稻稻瘟病菌Magnaporthe oryzae的抑制率为60.07%,优于对照药剂咯菌腈(58.21%)。杀虫与杀螨活性测定结果显示:在浓度为0.20 mmol/L时,大部分目标化合物对斜纹夜蛾Spodoptera litura和朱砂叶螨Tetranychus cinnabarinus雌成螨具有一定的杀虫和杀螨活性,但均低于对照药剂虫螨腈(100%)。杀线虫生物测定结果显示:在浓度为0.20 mmol/L时,大部分目标化合物表现出优异的杀线虫活性,其中化合物 5k 、 5r 和 5s 对秀丽隐杆线虫Caenorhabditis elegans的LC₅₀值分别为0.0918、0.0733和0.0810 mmol/L,优于对照药剂噻唑膦(0.2798 mmol/L)。本研究所合成的目标化合物具有一定的杀菌、杀虫、杀螨和杀线虫活性,可为溴代吡咯腈衍生物的设计和合成提供参考。     

α[3-(2,2-二氯乙烯基)-2,2-二甲基环丙基甲酰氧基烷基]膦酸酯的合成及生物活性研究

以二氯菊酰氯和α-羟基烃基膦酸酯为中间体合成了14种新的二氯菊酰氧基膦酸酯类化合物,其结构均通过1H NMR、MS、IR确证。对合成的化合物进行了杀虫、抑菌活性测试。结果表明,在250 mg/L的浓度下,部分化合物对蚕豆蚜虫有较好的毒杀作用,在50 mg/L浓度下部分化合物有一定的抑菌活性。     

吡啶联三唑类衍生物的合成及杀虫活性

以3-氨基-2-氯吡啶(1)为起始原料,经重氮化、叠氮化、环合和酰氯化反应,生成1-(2-氯吡啶-3-基)-5-甲基-1H-1,2,3-三唑-4-甲酰氯(5),(5)与取代苯胺反应,制得13个未见文献报道的吡啶联三唑类化合物,其结构通过 1H NMR和LC-MS表征。初步生物活性测定结果表明:在500 mg/L质量浓度下,所有目标化合物对粘虫 Mythimna separate 均有一定的杀虫活性,部分化合物致死率达100%;但在100 mg/L下,除化合物ZJ-7的致死率仍达100%外,其余化合物的活性明显降低,甚至无活性。     

Mode of action and pesticidal activity of the natural product dunnione and of some analogues

This paper reports the investigation of the insecticidal and fungicidal activity of dunnione, a natural product obtained inadvertently as a by-product of a synthesis programme. Dunnione exhibits no insecticidal activity but has an unusually broad spectrum of antifungal activity. In vitro and in vivo (preventative) activities were comparable to those of several long-established fungicides (eg carbendazim). However, in whole-plant assays, its eradicant activity was unexpectedly low, probably due to poor dose-transfer from leaf surface to fungus. The level of residual activity appears to be influenced by the formulation. Finally, its potential as a lead structure was assessed, and several analogues synthesised which exhibited high activity in the in vitro assays. Mode-of-action studies revealed that dunnione exerts its action primarily through initiation of redox cycling. This contrasts to the activity of BTG 505, the biochemical/chemical precursor, which does not initiate redox cycling but instead exhibits both insecticidal and fungicidal activity by inhibiting mitochondrial Complex III.