Novel pyrethrin derivatives containing an 1,3,4-oxadiazole thioether moiety: Design,synthesis, and insecticidal activity

In this study, a series of novel pyrethrin derivatives containing an 1,3,4-oxadiazole thioether moiety were designed and synthesized. Bioassay results revealed that some of the target compounds possessed excellent insecticidal activities against Plutella xylostella (P. xylostella), Vegetable aphids (V. aphids), and Empoasca vitis (E. vitis), respectively. In particular, compound 4l revealed the best insecticidal activities against P. xylostella and V. aphids, with the 50% lethal concentration (LC₅₀) values of 1.78 and 1.61 mg/L, respectively, meanwhile, compound 4k revealed the best insecticidal activity against E. vitis, with the LC₅₀ value of 1.06 mg/L, which were superior to those of the commercial insecticidal agents of chlorpyrifos, beta cypermethrin, spinosad, and azadirachtin. These results indicated that novel pyrethrin derivatives containing an 1,3,4-oxadiazole thioether moiety could effectively inhibit P. xylostella, V. aphids, and E. vitis.     

Synthesis,insecticidal activities,and structure–activity relationships of 1,3,4-oxadiazole-ring-containing pyridylpyrazole-4-carboxamides as novel insecticides of the anthranilic diamide family

The preparation of novel anthranilic diamide derivatives is extremely important for agricultural pest control. In this study, pyridylpyrazole-4-carboxamides containing a 1,3,4-oxadiazole ring were designed and synthesized via the dehydration of aromatic hydrazine derivatives and formanilides in the presence of an alkali. The insecticidal activities of these new compounds against the diamondback moth (Plutella xylostella) were evaluated. N-(4-chloro-2-methyl-6-(5-(4-nitrophenyl)-1,3,4-oxadiazol-2-yl)phenyl)-5-methyl-1-(pyridin-2-yl)-1H-pyrazole-4-carboxamide ( 8h6 ) showed 67%, 50%, 34%, 20%, and 17% activity at concentrations of 100, 50, 10, 5, and 1 μg ml⁻¹, respectively. Density functional theory calculations showed that the introduction of the 1,3,4-oxadiazole ring significantly changed the electron distributions in both the highest occupied and lowest unoccupied molecular orbitals, resulting in these compounds having much larger energy gaps than the well-known insecticide chlorantraniliprole, which may account for their lower activity. The results of this study demonstrate that anthranilic diamides substituted with a 1,3,4-oxadiazole ring are effective insecticides that can be used for pest management.     

2-取代硫醚-5-(5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶基)-1,3,4-噁二唑/噻二唑类化合物的合成及生物活性

以5-氨基-1H-1,2,4-三唑-3-羧酸乙酯为起始原料, 设计合成了11个新型的2-取代硫醚-5-(5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶基)-1,3,4-噁二唑类化合物(5)和6个新型的2-取代硫醚-5-(5,7-二甲基-1,2,4-三唑并[1,5-a]嘧啶基)-1,3,4-噻二唑类化合物(8). 通过¹H NMR, MS和元素分析对所合成的化合物进行了结构表征. 初步的生物活性测试结果表明, 所合成的化合物均表现出不同程度的除草及杀菌活性, 其中化合物5k和8f的活性最好, 在50 mg/L浓度下对水稻纹枯病菌的抑制率达90%以上.     

One-potCuAAC synthesis of (1H-1,2,3-triazol-1-yl)methyl-1,3,4/1,2,4-oxadiazoles starting from available chloromethyl-1,3,4/1,2,4-oxadiazoles

The one-pot CuAAC synthesis of (1H-1,2,3-triazol-1-yl)methyl-1,3,4-oxadiazole and (1H-1,2,3-triazol-1-yl)methyl-1,2,4-oxadiazole derivatives via three-component reaction of consequent nucleophilic substitution of chlorine, with azide, and its further “click” reaction, with alkynes, in the presence of CuI was studied. The utility of newly synthesized 2-(azidomethyl)-1,3,4/1,2,4-oxadiazoles and chloromethyl-1,3,4/1,2,4-oxadiazole derivatives was explored, and their limitations were determined. Novel 5-([4-aryl-1H-1,2,3-triazol-1-yl]methyl)-3-(aryl)-1,2,4-oxadiazoles, 2-([4-aryl-1H-1,2,3-triazol-1-yl]methyl)-5-(aryl)-1,3,4-oxadiazoles were obtained in good yields.     

2-(4-β-D-吡喃阿洛糖苷-苯基)-5-取代芳基-1,3,4-噁二唑的合成及镇静活性研究

以豆腐果苷为原料, 与取代苯甲酰肼反应生成中间体4-β-D-吡喃阿洛糖苷-苯甲醛取代苯甲酰腙(2a～2g), 在溴作催化剂的条件下发生关环反应, 合成了一系列豆腐果苷类似物3a～3g. 所有化合物结构经IR, ¹H NMR以及MS谱得以证实. 初步药理实验结果表明, 化合物3a, 3c, 3f与豆腐果苷相比有更好的镇静活性.     

Synthesis and antiviral activity of novel thioether derivatives containing 1,3,4-oxadiazole/thiadiazole and emodin moieties

A series of novel thioether derivatives containing 1,3,4-oxadiazole/thiadiazole and emodin moieties were designed and synthesized. The structures of the target compounds were confirmed by ¹H NMR, ¹³C NMR, Infrared, and elemental analysis. The results of bioactivity analysis showed that most of the target compounds exhibited moderate to good antiviral activity against tobacco mosaic virus at a concentration of 500 mg/L. Especially, among the title compounds, Y2, Y8, and Y10 possessed appreciable curative activity in vivo, with inhibition rates of 50.51, 52.08, and 54.62%, respectively, which were similar to that of Ningnanmycin (53.40%).     

1,2,4-Oxadiazole ring–containing pyridylpyrazole-4-carboxamides: Synthesis and evaluation as novel insecticides of the anthranilic diamide family

Herein, we describe the preparation of pyridylpyrazole-4-carboxamides containing a 1,2,4-oxadiazole ring as novel anthranilic diamide derivatives and compare their insecticidal activities to that of chlorantraniliprole, a well-established potent insecticide. Biological activity tests reveal that all compounds had good insecticidal activities, with the most potent species achieving diamondback moth (Plutella xylostella) mortalities of 100% and 57% at concentrations of 400 and 200 μg mL⁻¹, respectively.     

NNS tridentate thiosemicarbazide and 1,3,4-thiadiazole-2-amine complexes of some transition metal ions: syntheses,structure and fluorescence properties

The reactions of Zn(II), Mn(II), and Ni(II) acetates with 1-picolinoyl-4-phenyl-3-thiosemicarbazide (Hppts) yielded [Zn(ppts)₂]·CHCl₃ (3), [Mn(ppts)₂]·THF (4), and [Ni(ppts)₂]·THF (5), respectively, but HgCl₂ gave a cyclized product N-phenyl-5-(pyridin-2-yl)-1,3,4-oxadiazole-2-yl-amine (2). The treatment of Hppts with conc. H₂SO₄ formed N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-yl-amine (1). Hppts is a nonfluorescent material, but 3, 4 and the cyclized products 1,3,4-oxadiazole/1,3,4-thiadiazole are fluorescent. The cyclized ligand N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-amine (1) formed [Zn(2-Hppt)₂(OAc)₂] (6) and [Cd₂(2-Hppt)₂(OAc)₂(μ-OAc)₂] (7) in which Cd(II) has a binuclear acetate-bridged seven coordinate pentagonal bipyramidal geometry. Complex 7 is also a fluorescent material with maximum emission at 425 nm at an excitation wavelength of 254 nm.     

Synthesis and characterization of mono- and bicyclic heterocyclic derivatives containing 1,2,4-triazole, 1,3,4-thia-, and -oxadiazole rings

A series of new N- and S-substituted 1,3,4-oxadiazole derivatives were synthesized. 5-Pyridin-3-yl-3-[2-(5-thioxo-4,5-dihydro-l,3,4-thiadiazol-2-yl)ethyl]-1,3,4-oxadiazole-2(3H)-thione and 5-[(5-(pyridin-3-yl)-1,3,4-oxadiazol-2-ylthio)methyl]-N-phenyl-1,3,4-thiadiazol-2-amine were formed by cyclization of 3-(5-pyridin-3-yl-2-thioxo-1,3,4-oxadiazol-3(2H)-ylpropanimidohydrazide and 2-[(5-pyridin-3-yl-1,3,4-oxadiazol-2-yl)thio]thiosemicarbazide with CS₂ and H₂SO₄. On the other hand, a number of new bicyclic 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole derivatives were synthesized. 6-Pyridin-3-ylbis[1,2,4]‐triazolo[3,4-b:4′,3′-d][1,3,4]thiadiazole-3(2H)-thione was synthesized by reaction of 6-(hydrazino)-3-pyridine-3-yl[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole with CS₂/KOH/EtOH. The structures of the newly synthesized compounds were elucidated by the spectral and analytical data IR, Mass, and ¹H NMR spectra. Correspondence: Adel A.-H. Abdel-Rahman, Department of Chemistry, Faculty of Science, Menoufia University, Shebin El-Koam, Egypt; Wael A. El-Sayed, National Research Centre, Department of Photochemistry, Cairo, Egypt.     

Design,synthesis, and insecticidal activity of novel isoxazole derivatives containing bisamide moiety

In this study, a total of 31 novel isoxazole derivatives containing bisamide moiety were synthesized and evaluated for their insecticidal activity against Plutella xylostella (P. xylostella). Bioassays indicated that some of the target compounds exhibited good insecticidal activity against P. xylostella. In particular, compound E26 revealed excellent insecticidal activity against P. xylostella, with a 50% lethal concentration (LC₅₀) value of 4.6 μg/mL, which was even better than those of chlorpyrifos (7.7 μg/mL), beta‐cypermethrin (12.8 μg/mL), and azadirachtin (10.2 μg/mL). These results indicated that isoxazole derivatives containing bisamide moiety could be developed as novel and promising insecticides. To the best of our knowledge, it is the first report on the insecticidal activity of this series of novel isoxazole derivatives containing bisamide moiety.     

Design,synthesis, crystal structure and bioactivity evaluation of novel diethyl (arylfuranyl)(arylpyrazolylamino)methanephosphonates

A series of novel arylpyrazole derivatives containing aminomethanephosphonate and phenylfuran moieties were designed, synthesized and characterized by ¹H NMR, ³¹P NMR and IR spectroscopy and elemental analyses. The single crystal structure of diethyl [5-(4-chlorophenyl)furan-2-yl][3-cyano-1-(2,3,4-trifluorophenyl)-1H-pyrazol-5-ylamino]methanephosphonate (4l) was determined by X-ray diffraction. Preliminary bioassays showed that these phosphonates exhibit satisfactory insecticidal activities against Culexpipiens and Musca domestica at 0.1%. In particular, compound 4l exhibited a most promising KT50 value, which is superior to that of Dextraltetramethrin® and similar to Prallehtrin®. The structure-activity relationship was also preliminarily investigated.     

Arbeiten über Phosphorsäure- und Thiophosphorsäure ester mit einem heterocyclischen Substituenten. 2. Mitteilung. Eine verbesserte Methode zur Herstellung von 1, 3, 4-Oxadiazol-2(3H) onen und von Thio- und Dithiophosphorsäure-O,O-dialkyl-S-[(1, 3, 4-oxadiazol-2(3H)-on-3-yl)-methyl]-estern

Some 1,3,4-oxadiazol-2(2H)-ones with aliphatic substituents in 5-position are prepared in good yields and converted via the 3-hydroxymethyl derivatives to the corresponding 3-chloromethyl derivatives which are suitable starting materials for the preparation of insecticidal O,O-dialkyl-S-[(5-subst.-1,3,4-oxidiazol-2(3H)-one-3-yl)-methyl]-thiophosphates and dithiophosphates.     

Structural design and insecticidal activity of 1,3,4-oxadiazole-ring containing pyridylpyrazole-4-carboxamides

The insecticidal activity of 1,3,4-oxadiazole-ring containing pyridylpyrazole-4-carboxamides against diamondback (Plutella xylostella) and noctuid (Spodoptera frugiperda) moths were evaluated. Only substitutions on the 1,3,4-oxadiazole moiety dictated bioreactivity, with 8q2 m-CF₃Ph being the most effective against Plutella xylostella, showing 80%–93% mortality at a concentration of 0.5–500 μg ml⁻¹ while the others remained inactive or less active (highest mortality being 63%). The larvicidal activity against Spodoptera frugiperda was inferior compared with that of Plutella xylostella, with the highest mortality being 33%. A crystal of 8q5 was obtained and analyzed, revealing the effects of intramolecular H-bonds and intermolecular π π interactions.     

A simple and efficient approach for the synthesis of a novel class aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives via intramolecular nucleophilic substitution reaction

In this study, we synthesized a new series of substituted aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives (6-24) in yields ranging from 42 to 70% with an interesting mechanism that involves internal nucleophilic substitution followed by an S_N2-type nucleophilic substitution. First, 1-(4-chlorophenyl)-2-((5-methyl-1,3,4-thiadiazol-2-yl)thio)ethanone (3) was synthesized from the reaction of 5-methyl-1,3,4-thiadiazole-2-thiol (1) with 2-bromo-1-(4-chlorophenyl)ethanone (2) in the presence of potassium hydroxide. Then, 1-(4-chlorophenyl)-2-((5-methyl-1,3,4-thiadiazol-2-yl)thio)ethanol (4) was synthesized by a reduction reaction of this compound using NaBH₄. Finally, 5-methyl-3-alkyl-1,3,4-thiadiazol-2(3H)-one derivatives (6-24), which are the target compounds, were synthesized from the reaction of this compound (4), which is a secondary alcohol with various alkyl halides (5a-n) in the presence of sodium hydride (NaH). This study presents an interesting reaction mechanism related to the synthesis of aliphatic 1,3,4-thiadiazol-2(3H)-one derivatives that is not recorded in the literature.     

两种新型双极有机小分子发光材料的合成与发光

设计和合成了两种新的具有“双极(bipolar)”性质和发光性能的有机小分子化合物N-[4-(5-(2-苯基喹啉-4)-1,3,4-噁二唑-2)苯基]-N'-苯基-N,N'-二苯基-1,1'-联苯基-4,4'-二胺(TPDOPQ)和N,N'-双{4-[5-(2-苯基喹啉-4-基)-1,3,4-噁二唑-2]苯基}-N,N'-二苯基-1,1'-联苯基-4,4'-二胺[TPD(OPQ)₂]. 用¹H NMR, MS和元素分析进行了表征, 研究了化合物的热稳定性和光致发光性质, 并用循环伏安法测定了其电化学性能. 结果表明, 这两种合成的有机化合物同时具备空穴传导和电子输入双重功能, 光致发光性能优良, 热稳定性好, 能形成均衡薄膜, 因此可作为制作有机电致发光器件的候选材料.     

Design and synthesis of novel quinoline derivatives bearing oxadiazole,isoxazoline, triazolothiadiazole,triazolothiadiazine, and piperazine moieties

A new series of 2,3-disubstituted quinoline derivatives were synthesized from 2-chloroquinoline-3-carbaldehyde. In the reaction sequence, acetanilide was cyclized to give 2-chloroquinoline-3-carbaldehyde 1 , which was transformed to 2-(4-phenylpiperazin-1-yl)quinolin-3-carbaldehyde 2 by reaction with 4-phenylpiperazine in DMF-containing anhydrous K₂CO₃; then, compound 2 was oxidized by iodine in methanol, and methyl 2-(4-phenylpiperazin-1-yl)quinoline-3-carboxylate 3 was synthesized. The key intermediate 4 , 4-amino-5-[2-(4-phenylpiperazin-1-yl)quinolin-3-yl]-4H-1,2,4-triazole-3-thiol, was prepared using the ester 3 by a series of step. Reaction of 5 with various aromatic carboxylic acids or phenacyl bromides yielded 1,2,4-triazolo[3,4-b][1,3,4]thiadiazoles 5a-c and 1,2,4-triazolo[3,4-b][1,3,4]thiadiazines 6a-c , respectively. Moreover, compound 2 condensed with o-phenylenediamine to give 2-[2-(4-phenylpiperazin-1-yl)quinolin-3-yl]-1H-benzimidazole 7 . Interaction of 7 and 2-chloromethyl-5-aryl-1,3,4-oxadiazoles in the presence of K₂CO₃ led to the title compounds 8a-c . Furthermore, 4,5-dihydroisoxazoline derivatives 9a-c were obtained by the reaction of readily accessible starting materials including 2-(4-phenylpiperazin-1-yl)quinolin-3-carbaldehyde 2 , 1-phenyl-2-(triphenylphosphoranylidene)ethanone and hydroximoyl chlorides under mild conditions in the presence of Et₃N. The hydrazone intermediates 10a-c were obtained by the condensation of 2 with aroylhydrazides in ethanol, then, refluxing in acetic anhydride yielded 3-acetyl-5-aryl-2-[2-(4-phenylpiperazin-1-yl)quinolin-3-yl]-2,3-dihydro-1,3,4-oxadiazoles 11a-c . Structures of these compounds were established by their elemental analysis, IR, ¹H NMR, and mass spectral data.     

Synthesis and Antibacterial Studies of Some Novel 2-(Coumarin-3-yl)-5-mercapto-1,3,4-oxadiazoles Containing 2,4,6-Trisubstituted s-Triazine Derivatives

A new series of 2-(coumarin-3-yl)-5-mercapto-1,3,4-oxadiazoles based on various aryl thiourea/ureas incorporating a 1,3,5-s-triazine moiety is reported. The components of this series have been obtained by the reaction of cyanuric chloride (1) with 2-(coumarin-3-yl)-5-mercapto-1,3,4-oxadiazole (2). The prepared 2-{(coumarin-3-yl-1,3,4-oxadiazolyl)-5-thio}-4,6-dichloro-s-triazine (3) was subsequently treated with morpholine (4) to form 2-{(coumarin-3-yl-1,3,4-oxadiazolyl)-5-thio}-4-(morpholino)-6-chloro-s-triazine (5). This was further treated with various substituted aryl urea/thioureas (6a–k/7a–k) to afford the title compounds 8a–k and 9a–k, which were and tested for their antibacterial activity (MIC) against different microorganisms. The structures of the novel synthesized compound have been established on the basis of ¹H NMR and FT-IR data together with elemental analysis.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis and debenzoylation products of two perbenzoylated 2-substituted 5-D-galactosyl-1,3,4-oxadiazoles

The synthesis of 2-(p-chlorophenyl)-5-[1′,2′,3′,4′,5′-penta-O-benzoyl-D-galactopentitol-1-yl]-1,3,4-oxadiazole is described. Its debenzoylation gave an equilibrium mixture of the 1,3,4-oxadiazole derivative without protection of the hydroxyl group and the N-benzoyl-D-galactono-1,4-lactonehydrazone. A similar equilibrium was observed by debenzoylation of 2-phenyl-5-[1′,2′,3′,4′,5′-penta-O-benzoyl-D-galactopentitol-1-yl]-1,3,4-oxadiazole. The ¹H, ¹³C nmr and ms spectra of these compounds are presented.     

Synthesis and Insecticidal Evaluation of Novel N‐pyridylpyrazole Derivatives Containing Diacylhydrazine/1,3,4‐Oxadiazole Moieties

Two series of novel N‐pyridylpyrazole derivatives containing diacylhydrazine/1,3,4‐oxadiazole moieties were designed and synthesized based on the structure of chlorantraniliprole and characterized via ¹H‐NMR, ¹³C‐NMR, IR, MS, and elemental analysis. The preliminary bioassay indicated that some of the title compounds I and II exhibited larvicidal activities against Mythimna separata with 90–100% death rates at 500 mg/L. The further test showed that these compounds had weak insecticidal activity against Mythimna separata and Plutella xylostella at 200 mg/L and might be not suitable as insecticide lead compound for further optimization.     

Synthesis of Novel Chiral C2-Symmetric Bisoxazoline Ligands Containing 2,5-Di( m -substituted)phenyl-1,3,4-oxadiazole

Abstract

Seven novel chiral C₂-symmetric substituted bisoxazoline ligands containing 2,5-di(m-substituted)phenyl-1,3,4-oxadiazole have been synthesized from 2,5-di-(m-carboxylphenyl)-1,3,4-oxadiazole and aminoalcohol by NaOH or Et₃N cyclization method via halogenated amide intermediate.