Discovery of novel 3-{[(5,5-dimethyl-4,5-dihydroisoxazol-3-yl)sulfonyl]methyl}benzo[d]isoxazole analogs as promising very long chain fatty acids inhibitors

Very long chain fatty acids (VLCFAs) are one of the most principal and promising targets for herbicides discovery. In order to explore and find novel VLCFAs inhibitors with higher herbicidal activity and improved crop safety, a variety of new 3-{[(5,5-dimethyl-4,5-dihydroisoxazol-3-yl)sulfonyl]methyl}benzo[d]isoxazole derivatives were reasonably designed and synthesized. The results of greenhouse experiments indicated that several compounds exhibited good herbicidal activity against Digitaria sanguinalis, Echinochloa crus-galli, and Setaria faberii at rates of 150 g ai/ha. Compounds g4 and h1 displayed promising herbicidal activity against D sanguinalis and E crus-galli at rates of 75 g ai/ha, which is better than commercial pyroxasulfone and S-metolachlor. Moreover, compound h1 displayed higher activity against E crus-galli, D sanguinalis, and S faberii than pyroxasulfone and S-metolachlor even at a rate of 37.5 and 18.75 g ai/ha. Furthermore, both of the compounds g4 and h1 were much safer to these tested crops, especially to rice, wheat and rape, at the rate of 150 g ai/ha than pyroxasulfone. Therefore, h1 may act as a new lead structure for novel herbicides discovery.     

Design,Synthesis, and Bioactivity Evaluation of Novel 3‐(Substituted Phenoxy)‐6‐Methyl‐4‐(3‐Trifluoromethylphenyl) Pyridazine Derivatives

Using 3‐(4‐cyano phenoxy)‐6‐methyl‐4‐(3‐trifluoromethylphenyl) pyridazine (compound A ) as a leading compound, a total of 24 novel 3‐(substituted phenoxy)‐6‐methyl‐4‐(3‐trifluoromethylphenyl) pyridazine derivatives containing two electron‐withdrawing groups on the benzene ring (acylamine and oxime ether) were synthesized. Their herbicidal, insecticidal activities were bioassayed, and the herbicidal activity of compound CD-2 against Brassica campestris was 97.6% at 300 g/ha, which was better than the commercial herbicide diflufenican at the this concentration and is equal to the activity of the leading compound A . Compound CD-4 , CD-5 , CJ-3 , and CJ-5 displayed excellent insecticidal activity against Aphis laburni Kaltenbach (>95%). The results show that the oxime ether substitutions exhibit better bleaching and herbicidal activity than the acylamine ones. The bleaching and herbicidal activity of para‐position substitutions is better than the meta‐position ones. It seems that the para‐position on the benzene ring of oxime ether pyridazine derivatives is one of the key active sites that affect their herbicidal activities.     

Synthesis and herbicidal activity of 2-cyano-3-(2-fluoro-5-pyridyl)methylaminoacrylates

A series of 2-cyano-3-(2-fluoro-5-pyridyl)methylaminoacrylates were synthesized as herbicidal inhibitors of photosystem II (PSII) electron transport. 2-Fluoro-5-pyridinemethylamine was prepared from 2-amino-5-methylpyridine, subsequent reaction with 2-cyano-3,3-dimethylthioacrylates or 2-cyano-3-methoxyacrylates to yield these title compounds. All of these compounds were confirmed by ¹H NMR, IR, mass spectrum and elemental analyses. Their herbicidal activities were evaluated. All of the title compounds showed excellent herbicidal activities to amaranth pigweed and rape in post-emergence treatment. At the rate of 150 g/ha, one compound exhibited similar activity to Cl-analogue. The replacement of chlorine by fluorine group showed the same herbicidal activity.     

新型4,4-二甲基异噁唑-3-酮衍生物的合成及生物活性研究

以Baylis-Hillman加成物为起始原料,设计并合成了5个结构新颖的4,4-二甲基异唑-3-酮衍生物。所合成的化合物经IR、1HNMR和元素分析确证。生物活性测试结果表明,所合成的目标产物在2000gai/ha的剂量下均具有较好的除草活性。中间体1-(2,4-二氯苯基)-2-溴甲基丙烯酸乙酯具有杀虫活性,在600gai/ha的剂量下对朱砂叶螨防效为100%。     

Synthesis and biological activity of novel 2-(3-trifluoromethylphenoxy)-4-trifluoromethylthiazole-5-carboxamide derivatives

Novel 2-(3-trifluoromethylphenoxy)-4-trifluoromethylthiazole-5-carboxamides were designed and synthesized utilizing ethyl 3-amino-4,4,4-trifluoro-2-butenoate as a starting material via six steps. Subsequently, their biological activities were evaluated in the greenhouse. Results indicated that several compounds have some insecticidal or fungicidal activity at 600 g ai/ha and 300 g ai/ha, respectively.     

Synthesis and biological activity of novel 2-methyl-4-trifluoromethyl-thiazole-5-carboxamide derivatives

Nine novel 2-methyl-4-trifluoromethylthiazole-5-carboxamide derivatives were designed and synthesized utilizing ethyl 4,4,4-trifluoroacetoacetate as a starting material. Subsequently, the biological activity of the compounds was evaluated in the greenhouse. Results indicated that all of the compounds have some fungicidal and insecticidal activity but no herbicidal activity. Compound 1 has fungicidal activity with 90% control of tomato late blight at 375 g ai/ha, while two compounds 2F and 2H show insecticidal activity with 80 and 100% control, respectively, against potato leafhopper at 600 g ai/ha.     

Design,synthesis and herbicidal activity of novel cyclic phosphonates with diaryl ethers containing pyrimidine

Abstract

Thirteen novel cyclic phosphates were rationally designed and synthesized by introducing diary ethers containing pyrimidine. All the target compounds were characterized by ¹H, ¹³C, ³¹P NMR and HRMS. The test of herbicidal activity indicated that most of the compounds showed good herbicidal activities against Amaranthus retroflexus. The compounds IA-2 (1-(5,5-dimethyl-2-oxido-1,3,2-dioxaphosphinan-2-yl)propyl-2-((4,6-dimethoxypyrimidin-2-yl)oxy)benzoate) and IA-3 ((5,5-dimethyl-2-oxido-1,3,2-dioxaphosphinan-2-yl)(phenyl)methyl-2-((4,6-dimethoxypyrimidin-2-yl)oxy)benzoate) exhibited remarkable post-emergency herbicidal activity against the tested monocotyledonous weed at the dosage of 112.5?g ai/ha.     

Synthesis and biological activity of novel phenyltriazolinone derivatives

Phenyltriazolinones are one of the most important classes of herbicides targeting the protoporphyrinogen oxidase enzyme. A series of triazolinone derivatives containing a strobilurin pharmacophore were designed and synthesized with the aim of discovering new phenyltriazolinone analogues with high activity. The herbicidal activity of the synthesized compounds was assayed and some of the test compounds displayed moderate herbicidal activity at 150 g ai/ha.     

Synthesis and Herbicidal Activities of Potassium Methyl 1-(Substituted Phenoxyacetoxy)alkylphosphonate

A series of potassium methyl 1-(substituted phenoxyacetoxy)alkylphosphonates(9a―9o) was designed and synthesized. The results of preliminary bioassays indicate that most of the title compounds possess excellent pre-emergence and post-emergence herbicidal activities against Brassica napus, Amaranthus mangostanus, Medicago sativa, Echinochloa crusgalli, and Digitaria sanguinalis at a dosage of 1500 g/ha(1 ha=10000 m²). Especially, potassium methyl 1-(2,4-dichlorophenoxyacetoxy)-1-(4-methylphenyl)methylphosphonate(9g) and potassium methyl 1-(2,4-dichlorophenoxyacetoxy)-1-(furan-2-yl)methylphosphonate(9j) show the best herbicidal activity against five tested weeds with more than 85% inhibitory rate in pre-emergence.     

Synthesis and Herbicidal Activity of 3-Acetyl-4-hydroxy-2,1-benzothiazine Derivatives

In order to develop a novel herbicide containing the 2,1-benzothiazine motif, a series of 3-acetyl-4- hydroxy-2,1-benzothiazine derivatives was synthesized. All the target compounds were confirmed by 1H NMR,13C NMR, and high-resolution mass spectrometry(HRMS).In addition,the crystal structure of compoimd T27 was detemiined by single crystal X-ray diflraction. The bioassay results showed that some of the 3-acetyl-4-hydroxy- 2,1-benzothiazine derivatives(T13, T15, T22, and T24) showed good herbicidal activity at a dosage of 100 pg/mL. Among them,compounds T22 and T24 showed promising post-emergent herbicidal activities against Brassica campestris and Amaranthus retroflexus even at a dosage of 375 g/ha(1ha=104 m^2) in the greeiiliouse test. Studies on the structure-activity relationship demonstrated that the type of acetyl group played an important role in the herbicidal activity, and that the introduction of a phenoxyacetyl group at the 3-position of 2,1-beiizothiazine was beneficial in improving the herbicidal activity. The present study also indicated that 3-phenoxyacetyl-4-hydroxy-2,1-benzothiazine could be a potential lead compound for fiirther development of novel 2,1 -benzothiazine-containing herbicides.     

Synthesis and Herbicidal Activities of 2-Methylpropan-2-aminium O-Methyl 1-（Substituted Phenoxyacetoxy）alkylphosphonates

A series of 2-methylpropan-2-aminium O-methyl 1-（substituted phenoxyacetoxy）alkylphosphonates （5a-5o） was selectively synthesized by reacting the corresponding O,O-dimethyl l-（substituted phenoxyacetoxy）-alkylphosphonates with an excess of 2-methylpropan-2-amine.The results of preliminary bioassays show that the title compounds exhibit moderate to good herbicidal activities against Brassica napus and Echinochloa crusgalli.Furthermore,compounds 5a-5j,which show much higher activities than compounds 5k-5o,were selected to further evaluate their post-emergence herbicidal activity at a dosage of 150 g/ha（l ha=10000 m2）.Especially,2-methylpropan-2-aminium O-methyl 1-[2-（4-chloro-2-methylphenoxy）acetoxy]butylphosphonate（5h） shows 100％ inhibitory effect on the growth of Brassica juncea and Amaranthus retroflexus,which is comparable with the commercial herbicide 2,4-dichlorophenoxy acetic acid（2,4-D）.     

N-[2,4-二取代-5-(3-甲基-2,6-二氧-4-三氟甲基-1,2,3,6-四氢嘧啶-1-基)苯基]酰亚胺类化合物的合成及除草活性

脲嘧啶类化合物具有显著的除草活性. 设计并合成了10个未见文献报道的N-[2,4-二取代-5-(3-甲基-2,6-二氧-4-三氟甲基-1,2,3,6-四氢嘧啶-1-基)苯基]酰亚胺类化合物, 其化学结构经1H NMR, IR, HPLC/MS和元素分析表征. 初步生物活性测定结果表明, 该类化合物具有一定的除草活性, 如9a, 9b, 9c, 9f, 9g和9h在有效成分75 g/hm2剂量下, 茎叶处理对苘麻(Abutilon theophrasti Medic )、刺苋(Amaranthus spinosus)等双子叶杂草的抑制率达90%以上.     

N-杂环甲基2-(4-杂芳氧基苯氧基)丙酰胺的合成及除草活性

以2-(4-羟基苯氧)丙酸为原料,设计合成了16个新的手性N-杂环甲基2-(4-杂芳氧基苯氧基)丙酰胺化合物,其化学结构经核磁共振、色谱-质谱、红外光谱及元素分析确证.初步生物活性测定结果表明,合成的化合物在2.25×103g/ha剂量时对单子叶杂草马唐(Digitaria sanguinalis)、稗草(Echinochloa crus-galli)及狗尾草(Setaria viridis)等均具有90%以上的活性;进一步活性及作物安全性测试表明,化合物(R)-(+)-N-[(6-氯吡啶-3-基)甲基]-2-[4-(3-氯-5-三氟甲基吡啶-2-基氧基)苯氧基]丙酰胺(2b)的除草活性高于噁唑酰草胺,且对水稻茎叶处理安全,同时对水稻田主要杂草千金子的活性远高于氰氟草酯;化合物的除草活性与立体构型有关,R构型为活性构型.     

Laboratory and Field Evaluation of the Phytotoxic Activity of Sapindus mukorossi Gaertn Pulp Extract and Identification of a Phytotoxic Substance

Interest in finding plant-based herbicides to supplement synthesized herbicides is increasing. Although the extract of Sapindus mukorossi Gaertn has been reported to have herbicidal activity, little is known about phytotoxic substances and their efficacy of weed control in the field. To identify phytotoxic substances, the bioassay-guided fractionation by column chromatography and high-speed counter-current chromatography (HSCCC) was carried out. The phytotoxic activity assay, performed by the agar medium method, showed that the 70% ethanol fraction exhibited strong root growth inhibition against Trifolium pratense with an 50% inhibitory concentration (IC₅₀) value of 35.13 mg/L. An active compound was isolated from the 70% ethanol fraction and identified as hederagenin 3-o-β-D-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside (Compound A). Compound A had an IC₅₀ value of 16.64 mg/L. Finally, a new formulation was prepared based on the 70% ethanol fraction, which exhibited good efficacy against broadleaf weeds in a carrot field. The fresh weight control efficacy was 78.7% by 45 days after treatment at the dose of 1500 g a. i./ha. Hence, the extract of S. mukorossi pulp could be a promising supplement to the synthesized herbicides. Furthermore, compound A from S. mukorossi may be responsible for its phytotoxic activity.     

含芳氧乙酰基和间-三氟甲基苯基的双酰胺化合物的合成及其除草活性

通过组合不同除草作用机制的活性基团,采用芳氧乙酸为酸组分的Ugi四组分反应合成了一系列芳氧乙酰基和间三氟甲基苯基片段的双酰胺化合物3a~3v,采用IR、¹H NMR、EI-MS和元素分析等技术手段对其结构进行了表征。 温室盆栽测试结果表明,部分目标化合物对油菜、反枝苋、稗草和马唐表现出中等至良好的除草活性,如化合物3r在温室盆栽时,在1.5 kg/ha剂量下,在苗前处理时对反枝苋和马唐显示出100%的抑制活性;在苗后处理时对马唐显示出100%的抑制活性。 初步探讨了目标化合物的构效关系。     

4-(7-甲氧基-2,2-二甲基-2,3-二氢苯并呋喃-5-基)-2-苄亚氨基噻唑的合成与生物活性

呋喃酚经醚化、傅克酰化、α-溴代、噻唑环化和亚胺化等反应合成了16种4-(7-甲氧基-2,2-二甲基-2,3-二氢苯并呋喃-5-基)-2-苄亚氨基噻唑新化合物.化合物的结构经1H NMR、质谱和元素分析等确证.杀虫活性实验结果表明,化合物2a和2i在500 mg/L对棉红蜘蛛死亡率分别为53.10%和67.71%,杀菌活性实验结果表明,化合物2a和2k在25 mg/L对油菜菌核病菌抑制率分别为57.9%和59.8%,除草活性实验结果表明,2l在2250 g.ai/ha浓度下对苘麻、刺苋、藜具有一定的除草活性.     

Parthenin—A Sesquiterpene Lactone with Multifaceted Biological Activities: Insights and Prospects

Parthenin, a sesquiterpene lactone of pseudoguaianolide type, is the representative secondary metabolite of the tropical weed Parthenium hysterophorus (Asteraceae). It accounts for a multitude of biological activities, including toxicity, allergenicity, allelopathy, and pharmacological aspects of the plant. Thus far, parthenin and its derivatives have been tested for chemotherapeutic abilities, medicinal properties, and herbicidal/pesticidal activities. However, due to the lack of toxicity–bioactivity relationship studies, the versatile properties of parthenin are relatively less utilised. The possibility of exploiting parthenin in different scientific fields (e.g., chemistry, medicine, and agriculture) makes it a subject of analytical discussion. The present review highlights the multifaceted uses of parthenin, on-going research, constraints in the practical applicability, and the possible workarounds for its successful utilisation. The main aim of this comprehensive discussion is to bring parthenin to the attention of researchers, pharmacologists, natural product chemists, and chemical biologists and to open the door for its multidimensional applications.     

3-(5′-乙氧基-1,3,4-噻二唑-2′-亚甲氨基)-2-氰基-3-取代-丙烯酸酯类化合物的合成、晶体结构及生物活性

采用氰基丙烯酸酯与5-乙氧基-1,3,4-噻二唑-2-甲氨在乙醇中加热回流的方法合成了一系列3-(5′-乙氧基-1,3,4-噻二唑-2′-亚甲氨基)-2-氰基-3-取代-丙烯酸酯类化合物.目标化合物结构均经1HNMR和元素分析确证.生物活性测试结果表明,部分化合物对双子叶杂草油菜和苋菜显示出较好的除草活性及良好的选择性,用化合物6j在600g/ha剂量下对油菜和苋菜茎叶进行处理,抑制率仍达100%和95.2%,与对照样B相当;氰基丙烯酸酯3位取代基体积对除草活性影响较大,3位为异丙基时活性最高.     

2-[2-(烷氧羰基苯氧羰基)苯氧基]-4,6-二甲氧基嘧啶类化合物的合成及其除草活性研究

为了寻找高效、安全、经济的除草活性化合物, 设计并合成了9个新的2-[2-(烷氧羰基苯氧羰基)苯氧基]-4,6-二甲氧基嘧啶类化合物, 其化学结构经IR, ¹H NMR, LC/MS和元素分析确证. 初步生物活性测定结果表明, 该类化合物在有效成份2250 g/ha剂量时, 对苘麻(Abutilon theophrasti)、稗草(Echinochloa crus-galli)、狗尾草(Setaria viridis)等都具有良好的除草活性, 抑制率达90％以上. 其中5b, 5e, 5h在187.5 g/ha剂量时, 仍具有良好的除草活性, 抑制率达90％以上.     

Synthesis and Herbicidal Activity of Novel N‐(2‐Fluoro‐5(3‐methyl‐2,6‐dioxo‐4‐(trifluoromethyl)‐2,3‐dihydro‐pyrimidin‐1(6H)‐yl)phenyl)‐2‐phenoxyacetamide Derivatives

Thirteen novel N‐(2‐fluoro‐5‐(3‐methyl‐2,6‐dioxo‐4‐(trifluoromethyl)‐2,3‐dihydropyrimidin‐1(6H)‐yl)phenyl)‐2‐phenoxy)acetamides were designed and synthesized utilizing 4‐fluoro‐aniline and ethyl 3‐amino‐4,4,4‐trifluoro‐but‐2‐enoate as starting materials. The chemical structures of all compounds were confirmed by ¹H NMR, IR, mass spectrum and elemental analyses. Subsequently, the herbicidal activities of the as‐prepared compounds were evaluated in the greenhouse. Bioassay results indicated that most of compounds had better herbicidal activities against dicotyledonous weeds. Among all the tested compounds, compounds 4a – 4i showed good herbicidal activities at both pre‐emergence and post‐emergence treatment against two or three kinds of dicotyledonous weeds, such as Abutilon theophrasti Medic, Amaranthus ascendens L, and Chenopodium album L at the dosage of 75 g ai/ha.