Discovery of a new insecticide lead by optimizing a target-diverse scaffold: Tetrazolinone derivatives

Synthesis, fungicidal activity, and 3D-QSAR of tetrazole derivatives containing phenyloxadiazole moieties

In an effort to discover new agents with good fungicidal activities against CDM (cucumber downy mildew), a series of tetrazole derivatives containing phenyloxadiazole moieties were designed and synthesized. The EC₅₀ values for fungicidal activities against CDM were determined. Bioassay results indicated that most synthesized compounds exhibited potential in vivo fungicidal activity against CDM. A CoMFA (comparative molecular field analysis) model based on the bioactivity was developed to identify some primary structural quality for the efficiency. The values of q² and r² for the established model were 0.791 and 0.982 respectively, which reliability and predict abilities were verified. Three analogues (q3, q4, q5) were designed and synthesized based on the model. All these compounds exhibited significant fungicidal activity on CDM with the EC₅₀ of 1.43, 1.52, 1.77 mg·L^-1. This work could provide a useful instruction for the further structure optimization.

Assessing Methodologies to Synthesize α-Sulfenylated Carbonyl Compounds by Green Chemistry Metrics

α-Sulfenylated carbonyl compounds are important both as active pharmaceutical ingredients and as intermediates in organic synthesis. Owing to their relevance in synthetic organic chemistry, this Minireview focuses on assessing the most relevant synthetic procedures based on green chemistry metrics. The Minireview starts with the traditional routes and then focuses on more recently developed methodologies. These routes include sulfenylating reagents using organocatalysis, cross-dehydrogenative couplings using in situ halogenations to prevent reactive intermediates in high concentrations, oxidative couplings using terminal oxidants such as DDQ or TEMPO, and redox-neutral couplings using transition metal catalysis. These methodologies have been evaluated on the basis of atom economy, E factor, and the safety and toxicity of the transformations and the solvents used. Besides using green metrics to evaluate these novel methodologies, the synthetic utility is also assessed with regard to the availability of starting materials and the generality of the reactions. This Minireview aims to inspire researchers to apply green assessments to other methodologies and also for them to take measures to increase the greenness of their developed transformations.

Cu2O nanoparticle-catalyzed synthesis of diaryl tetrazolones and investigation of their solid-state properties

1,4-Diaryl tetrazolones 1 have been synthesized by Cu₂O nanoparticle-catalyzed C–N coupling of aryl tetrazolones 2 with aryl boronic acids 3 in the presence of oxygen, and their crystal structures have been reported.

Study of the in vivo antiviral activity against TMV treated with novel 1-(t-butyl)-5-amino-4-pyrazole derivatives containing a 1,3,4-oxadiazole sulfide moiety

A series of new 1-tert-butyl-5-amino-4-pyrazole bioxadiazole sulfide derivatives containing a 1,3,4-oxadiazole moiety were designed and synthesized. The bioactivity results showed that some title compounds exhibited excellent protective activity against TMV and certain insecticidal activity. Among the tested compounds, the EC₅₀ values of 5d, 5j, 5k and 5l were 165.8, 163.2, 159.7 and 193.1 mg/L, respectively, which are better than the EC₅₀ value of ningnanmycin (271.3 mg/L). The chlorophyll contents and the defense enzyme activities of the tobacco leaves after treatment with 5j were significantly increased, which indicated that this series of title compounds may induce the systemic acquired resistance of host to defend against diseases. Further in vivo protective activity research on 5j using TMV with a GFP gene tag found that it can effectively inhibit the spread of TMV in inoculated tobacco. A morphological study with TEM revealed that title compound 5h can cause a distinct break of the rod-shaped TMV. Moreover, the insecticidal activity revealed that the fatality rates of 5a, 5b and 5m against aphidoidea were 85%, 83% and 87%, respectively, which indicated that the title compounds can effectively block the common carrier of plant viruses, thereby effectively reducing the TMV infection risk of tobacco. This series of synergistic effects provide key information for the research and development of antiviral agents.

Design, Synthesis, and Insecticidal Activity of Novel Doramectin Derivatives Containing Acylurea and Acylthiourea Based on Hydrogen Bonding

Our recent investigation on the insecticidal activities of several doramectin derivatives preliminarily revealed that the presence of hydrogen bonds at the C4″ position of the molecule with target protein γ-aminobutyric acid (GABA) receptor was crucial for retaining high insecticidal activity. As a continuation of our research work on the development of new insecticides, two series of novel acylurea and acylthiourea doramectin derivatives were designed and synthesized. The bioassay results indicated that the newly synthesized compounds (5o, 5t, and 6t) exhibited higher insecticidal activity against diamondback moth, oriental armyworm, and corn borer than the control compounds doramectin, commercial avermectins, chlorbenzuron, and lead compound 3g in our laboratory. Specifically, compound 5t was identified as the most promising insecticide against diamondback moth, with a final mortality rate of 80.00% at the low concentration of 12.50 mg/L, showing approximately 7.75-fold higher potency than the parent doramectin (LC₅₀ value of 48.1547 mg/L), 6.52-fold higher potency than commercial avermectins (LC₅₀ value of 40.5507 mg/L), and 3.98-fold higher potency than compound 3g (LC₅₀ value of 24.7742 mg/L). Additionally, molecular docking simulations revealed that compound 5t (2.17, 2.20, 2.56, and 2.83 Å) displayed stronger hydrogen-bond action in binding with the GABA receptor, better than that of compound 5o (1.64 and 2.15 Å) and compound 6t (2.20 and 2.31 Å) at the C4″ position. This work demonstrated that these compounds containing hydrogen-bond groups might contribute to the improvement of insecticidal activity and supply certain hints toward structure optimization design for the development of new insecticides.

Design, synthesis and antimicrobial activities of novel 1,3,5-thiadiazine-2-thione derivatives containing a 1,3,4-thiadiazole group

A series of novel 1,3,5-thiadiazine-2-thione derivatives containing a 1,3,4-thiadiazole group was designed and synthesized. The structures of all the compounds were well characterized using ¹H NMR, ¹³C NMR and high-resolution mass spectrometer, and further confirmed by the X-ray diffraction analysis of 8d. The antimicrobial activities of all the target compounds against Xanthomonas oryzae pv. oryzicola, X. oryzae pv. oryzae, Rhizoctonia solani and Fusarium graminearum were evaluated. The in vitro antimicrobial bioassays indicated that some title compounds exhibited noteworthy antimicrobial effects against the above strains. Notably, the compound N-(5-(ethylthio)-1,3,4-thiadiazol-2-yl)-2-(5-methyl-6-thioxo-1,3,5-thiadiazinan-3-yl)acetamide (8a) displayed obvious antibacterial effects against X. oryzae pv. oryzicola and X. oryzae pv. oryzae at 100 μg/mL with the inhibition rates of 30% and 56%, respectively, which was better than the commercial bactericide thiodiazole-copper. In addition, the anti-R. solani EC₅₀ value of 8a was 33.70 μg/mL, which was more effective than that of the commercial fungicide hymexazol (67.10 μg/mL). It was found that the substitutes in the 1,3,5-thiadiazine-2-thione and the 1,3,4-thiadiazole rings played a vital role in the antimicrobial activities of the title compounds. More active title compounds against phytopathogenic microorganisms might be obtained via further structural modification.

Synthesis and insecticidal activity studies of novel phenylpyrazole derivatives containing arylimine or carbimidate moiety

Phenylpyrazole insecticides are successful for crop protection and public hygiene by blocking gamma-aminobutyric acid (GABA)-gated chloride channels and glutamate-gated chloride (GluCl) channels. A series of novel phenylpyrazoles containing arylimine or 1-methoxyaryl groups were designed and synthesized. The addition reaction of methanol to the imines 1-11 was investigated and the cayno addition products 13-15 were obtained. The compounds 1-15 were confirmed by ¹H NMR and elemental analysis. The results of bioassay indicated that some compounds exhibited comparable bioactivity to fipronil against a broad spectrum of insects such as bean aphid (Aphis craccivora), mosquito (Culex pipiens pallens), diamondback moth (Plutella xylostella) and Oriental armyworm (Mythimna separata). Especially, the foliar contact activity against bean aphid of compound 7 at 10 µg mL^-1 was 68%, the larvacidal activity against mosquito of compounds 5, 13 and 15 at 0.0025 µg mL^-1 was 100%, the larvacidal activity against diamondback moth of compounds 9 and 11 at 0.05 µg mL^-1 was 100%, the larvacidal activity against Oriental armyworm of compound 9 at 1 µg mL^-1 was 100%. The 3-cayno moiety on pyrazole ring was essential for the high insecticidal activities against bean aphid, diamondback moth and Oriental armyworm, while the 3-carbimidate moiety on pyrazole ring was crucial to the excellent high insecticidal activities against mosquito.

Design, synthesis and biological evaluation of novel α-aminophosphonate oxadiazoles via optimized iron triflate catalyzed reaction as apoptotic inducers

α-aminophosphonate oxadiazoles (5a-m) were prepared in high yields by reacting of 1,3,4-oxadiazole acetohydrazide (3) with appropriate aldehydes and diethyl phosphite under Kabachnik-Fields conditions using Iron triflate as a catalyst. The reaction conditions were optimized using D-optimal experimental design. Possible reaction mechanisms were considered, and structures of the new products were based upon compatible elementary and spectroscopic evidence. In vitro antitumor activities of these compounds were evaluated against human cancer cell lines of colon (HCT116), breast (MCF7) and liver (HepG2) and compared with anticancer drug, Doxorubicin, employing standard MTT assay. Compounds 5i and 5l demonstrated good antiproliferative activities against HCT116 tumor cells comparable to doxorubicin with low cytotoxicity towards normal fetal colon cell (FHC). Additionally, their capacity to activate apoptosis cascade was studied in HCT116 cell line by investigating the activation of proteolytic caspases cascade, the levels of Cytochrome C, Bax and Bcl-2. Active caspase-3 level was enhanced by 6-8-folds in HCT116 cell line when stimulated with compounds 5i and 5l compared to the control. The level of Caspases 8 & 9 was also increased signifying that intrinsic and extrinsic pathways are both activated. They also induced Bax and down regulated Bcl-2 protein level in addition to over-expressing Cytochrome C level in HCT116 cell line. Also, HCT116 cell cycle was mainly arrested at the Pre-G1 and G2/M phases when treated with compounds 5i and 5l.

Design, synthesis, insecticidal activity and molecular docking of doramectin derivatives

A series of new doramectin derivatives containing carbamate, ester and sulfonate were synthesized, and their structures were characterized by ¹H and ¹³C nuclear magnetic resonance (NMR) and high-resolution mass spectrum (HRMS). Their insecticidal activities against oriental armyworm, diamondback moth, and corn borer were evaluated and compared with the parent doramectin and commercial avermectins, metolcarb, fenpropathrin. Among all compounds, three compounds (3a, 3g and 3h) showed excellent insecticidal effect. In particular, compound 3g containing cyclopropyl carbamate against oriental armyworm, diamondback moth, and corn borer, exhibited the most promising insecticidal activity with the final mortality rate of 66.67%, 36.67%, 40.00% at the concentration of 12.5 mg/L, respectively. The LC₅₀ values of 3g were 5.8859, 22.3214, and 22.0205 mg/L, showing 6.74, 2.23, 2.21-fold higher potency than parent doramectin (LC₅₀ values of 39.6907, 49.7736, and 48.6129 mg/L) and 6.83, 1.93, 3.36-fold higher potency than commercial avermectins (LC₅₀ values of 40.2489, 42.9922, and 73.9508 mg/L). Additionally, molecular docking simulations revealed that 3g displayed stronger hydrogen-bonding action in binding with the GABA receptor than parent doramectin, which were crucial for keeping high insecticidal activity. The present work demonstrated that these compounds containing alkyl carbamate group could be considered as potential candidates for the development of novel pesticides in the future.

Design, synthesis, and insecticidal activity evaluation of novel 4-(N, N-diarylmethylamines)furan-2(5H)-one derivatives as potential acetylcholine receptor insecticides

BACKGROUND

Flupyradifurone is a member of a novel class of insecticides that possess excellent insecticidal activities. Halogen-containing phenyl groups are important and indispensable structural components of many pesticides. However, replacement of the difluoromethyl group of flupyradifurone with halogen-containing phenyl groups has not been reported. Hence, a series of novel butenolide derivatives containing phenyl groups were synthesized and bioassayed to discover novel compounds with excellent insecticidal activities.

RESULTS

Some target molecules exhibited good insecticidal activities against Aphis craccivora. Among the title compounds, 4cc showed the best insecticidal activities with an 50% lethal concentration (LC₅₀ ) value of 1.72 μg mL^-1 , which is superior to that of pymetrozine (LC₅₀  = 6.86 μg mL^-1 ). Molecular docking indicated that 4cc lacks oxidative metabolism by CYP6CM1 and metabolic resistance with imidacloprid. Furthermore, label-free quantitative proteomic analysis indicated that 4cc may be a potential acetylcholine receptor insecticide that acts on the nicotinic acetylcholine receptor. Compound 4cc also decreased the capability for oxidative metabolism, which further supported the molecular docking results.

CONCLUSION

This work can be used to further investigate the mechanism underlying the insecticidal activity of butenolide derivatives and develop potential novel butenolide insecticides. © 2018 Society of Chemical Industry.

Regioselective Sulfenylation of α'-CH3 or α'-CH2 Groups of α,β-Unsaturated Ketones with Heterocyclic Thiols

A rare regioselective sulfenylation of α'-CH₃ or α'-CH₂ bonds adjacent to α,β-unsaturated ketones using dimethyl sulfoxide as an oxidant and a substoichiometric amount of aq HI as an additive is described. This methodology employs a strong acid such as aq HI or iodine and exhibits a high regioselectivity without undergoing conjugate addition, which is difficult to achieve under the cross dehydrogenative coupling method.

Synthesis and biological activities of novel 1,3,4-thiadiazole-containing pyrazole oxime derivatives

A new library of 1,3,4-thiadiazole-containing pyrazole oximes was designed and synthesized. Their acaricidal and insecticidal activities were evaluated. Bioassay results indicated that some target compounds exhibited good acaricidal and insecticidal properties. Especially, compound 8m had 80% acaricidal activity against Tetranychus cinnabarinus at the concentration of 50μg/mL, compound 8f displayed 100% insecticidal activities against Aphis craccivora at the concentration of 50μg/mL, compounds 8r and 8w showed 100% insecticidal activities against Plutella xylostella at the concentration of 50μg/mL. Furthermore, compounds 8r (LC50=19.61μg/mL) and 8w (LC50=9.78μg/mL) possessed comparable or even better insecticidal activities than the control Pyridalyl (LC50=17.40μg/mL) against P. xylostella.

Synthesis, structural characterization and theoretical approach of 3-(2,6-dichlorobenzyl)-5-methyl-N-nitro-1,3,5-oxadiazinan-4-imine

3-(2,6-Dichlorobenzyl)-5-methyl-N-nitro-1,3,5-oxadiazinan-4-imine (DNOI) was synthesized and characterized by X-ray diffraction, FT-IR, FT-Raman and UV-Vis spectra. The X-ray diffraction study showed that DNOI has a one dimensional configuration, due to the intermolecular C9H⋯O1 and N4H⋯O2 hydrogen bonds. The benzene ring and the oxadiazine rings are tilted with respect to each other by 63.07° (C3N1C5C6). Vibrational spectra and electronic spectra measurements were made for the compound. Optimized geometrical structure and harmonic vibrational frequencies were computed with DFT (B3LYP, B3P86, and M062X) methods using 6-311++G(d,p) basis set. Assignments of the observed spectra were proposed. The equilibrium geometries computed by all of the methods were compared with X-ray diffraction results. The absorption spectra of the title compound were computed both in gas phase and in CH3OH solution using TD-B3LYP/6-311++G(d,p) and PCM-B3LYP/6-311++G(d,p) approaches, respectively. The calculated results provide a good description of positions of the bands maxima in the observed electronic spectrum. Temperature dependence of thermodynamic parameters in the range of 100-1000K were determined, entropy, heat capacity and enthalpy changes were increasing with temperature increasing, while for Gibbs free energy is decreasing with temperature increasing. The bond orbital occupancies, contribution from parent natural bond orbital (NBO), the natural atomic hybrids was calculated and discussed.

Support vector machine (SVM) classification model based rational design of novel tetronic acid derivatives as potent insecticidal and acaricidal agents

A novel SVM classification model was constructed and applied in the development of novel tetronic acid derivatives as potent insecticidal and acaricidal agents.

Advances in chemistry of chromone aminomethyl derivatives

Chromones play an important role in the design and discovery of new pharmacologically active compounds. A large volume of reports dedicated to synthesis and study of properties of nitrogen-containing chromone derivatives show important role of chromone alkaloid-like compounds. The present review covers achievements in the field of synthesis of chromone aminomethyl derivatives as one of perspective scaffolds.

Evaluation of etoxazole against insects and acari in vegetables in China

Etoxazole, 2-(2,6-difluorophenyl-4-[4-(1,1-dimethylethyl)-2-ethoxy-phenyl]-4,5-dihydrooxazole, an organofluorine chitin synthesis inhibitor, was assayed for its bioactivities against several major insect and acarus pests and compared to several other pesticides: two chitin synthesis inhibitors, hexaflumuron and chlorfluazuron; a pyrethroid, permethrin; an organophosphate, acephate; a carboximide, hexythiazox; and a tetrazine, clofentezine. The LC50 of etoxazole was calculated using probit analysis of the concentration-dependent mortality data against susceptible and resistant strains of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae); diamondback moth, Plutella xylostella L. (Plutellidae); bean aphid, Aphis craccivora Koch (Hemiptera: Aphididae); and carmine spider mite, Tetranychus cinnabarinus (Boisduval) Boudreaux (Trombidiformes: Tetranychidae). The resistant strains were found to be resistant against all tested pesticides except etoxazole. The bioactivity of etoxazole was many times that of the other tested insecticides and acaricides widely used in vegetable crops in China. On the basis of our research, etoxazole can be expected to be extensively used on vegetable crops in China.

Synthesis, molecular modeling and biological evaluation of N-benzylidene-2-((5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl)thio)acetohydrazide derivatives as potential anticancer agents

A series of new 1,3,4-oxadiazole derivatives (6a-6x) containing pyridine and acylhydrazone moieties were synthesized and developed as potential telomerase inhibitors. The bioassay tests demonstrated that compounds 6n, 6o, 6q, 6s and 6t exhibited significant broad-spectrum anticancer activity with IC₅₀ range from 0.76 to 9.59 μM against the four cancer cell lines (HEPG2, MCF7, SW1116 and BGC823). Moreover, all the title compounds were assayed for telomerase inhibition using the TRAP-PCR-ELISA assay. Compound 6s showed the highest anticancer activity with IC₅₀ of 0.76-1.54 μM against the tested cancer cell lines and exhibited the most potent telomerase inhibitory activity with IC₅₀ of 1.18 ± 0.14 μM. The docking simulation was carried out to investigate a possible binding mode of compound 6s into the active site of telomerase (pdb. 3DU6) while the QSAR model was built to check the previous work as well as to introduce new directions.

Metabolism-based synthesis, biological evaluation and structure-activity relationship analysis of spirotetramat analogues as potential lipid biosynthesis inhibitors

BACKGROUND

In previous studies, scientists found that, when spirotetramat was introduced into plants or animals, it was mainly metabolised at positions C-4 and C-8. That is to say, these two functional positions potentially played an important role in spirotetramat's bioactivities. In order to develop novel insecticides or miticides, the present authors designed and synthesised 35 spirotetramat analogues based on metabolite structures.

RESULTS

All of the analogues have been identified on the basis of (1)H NMR, ESI-MS and elemental analysis data. The activities of these analogues were evaluated against three organisms, and biological assays indicated that compounds 5f, 5h and 5u possessed better insecticidal activities against bean aphids (Aphis fabae) than the lead compound spirotetramat. The LC50 of 5f, 5h and 5u against bean aphids reached 0.42, 0.28 and 2.53 mg L(-1) respectively. Moreover, some compounds possessed comparable activities against carmine spider mite (Tetranychus cinnabarinus) and oriental armyworm (Mythimna sepatara) with spirotetramat. The structure-activity relationships (SARs) indicated that the flexible bridge at position C-4 of spirotetramat was important for its bioactivities, and the size of the group at position C-8 would have great influence on the activities. Furthermore, the log P values lower than 6.0 may be favourable for insecticidal activities.

CONCLUSION

The present work demonstrates that some spirotetramat analogues can be used as potential lead compounds for developing novel insecticides, and preliminary SAR analysis would provide information for the utilisation of spirotetramat analogues as potential lipid biosynthesis inhibitors.

Design, synthesis, and insecticidal evaluation of new pyrazole derivatives containing imine, oxime ether, oxime ester, and dihydroisoxazoline groups based on the inhibitor binding pocket of respiratory complex I

On the basis of complex I receptor protein binding site and commercial tebufenpyrad and tolfenpyrad, four series of novel pyrazole-5-carboxamides containing imine, oxime ether, oxime ester, and dihydroisoxazoline were designed and synthesized via the key intermediate 4-chloro-3-ethyl-N-(4-formylbenzyl)-1-methyl-1H-pyrazole-5-carboxamide. The structures of target compounds were confirmed by ¹H NMR and high-resolution mass spectrum (HRMS). The results of bioassays indicated that the target compounds possessed good-to-excellent activities against a broad spectrum of insects such as cotton bollworm (Helicoverpa armigera), spider mite (Tetranychus cinnabarinus), bean aphid (Aphis craccivora), and mosquito (Culex pipiens pallens), but gave different structure-activity relationships for each species. Compounds containing imine showed high insecticidal activity against cotton bollworm. Especially, stomach activity of compounds 5-1c was 60% at 11 mg kg⁻¹. The compounds also had good activities against bean aphid and mosquito. The foliar contact activity of compounds 5-1a, 5-1b, 5-1e, 5-3c, and 5-3d against bean aphid were 90, 100, 90, 90, and 90%, respectively, at 200 mg kg⁻¹. The activity of compound containing dihydroisoxazoline moiety (5-4) against mosquito was 60% at 1 mg kg⁻¹, which was near that of tebufenpyrad. The introduction of dihydroisoxazoline structure (5-4) was advantageous to improve the activity of the compound against adult mites compared with other structures; the miticidal activity of 5-4- against adult mites was 60% at 50 mg kg⁻¹.

Synthesis, molecular modeling and biological evaluation of 2-aminomethyl-5-(quinolin-2-yl)-1,3,4-oxadiazole-2(3H)-thione quinolone derivatives as novel anticancer agent

A series of quinoline derivatives (4a-4o) have been synthesized and their biological activities were also evaluated as potential telomerase inhibitors. Bioassay tests demonstrated that most of the compounds exhibited substantial broad-spectrum antitumor activity against the three cancer cell lines (HepG2, SGC-7901 and MCF-7). Moreover, all the title compounds were assayed for telomerase inhibition using the TRAP-PCR-ELISA assay. Compounds 4d and 4i displayed the most potent anticancer activities, which were comparable to the positive control. Docking simulation was performed to position compounds 4d and 4i into the telomerase structure active site to determine the probable binding model. Compounds 4d and 4i with potent inhibitory activity in tumor growth inhibition may be potential anticancer agents.

Synthesis and bioactivity study of 2-acylamino-substituted N'-benzylbenzohydrazide derivatives

The discovery of new safe and effective pesticides is one of the main means of providing eco-friendly agricultural agents for modern crop protection. To identify new biological molecules based of the anthranilic diamide skeleton of the novel pesticide chlorantraniliprole, which acts on the ryanodine receptor and functional groups in acyl hydrazine insect growth regulators, more than 40 new compounds of 2-acylamino-substituted N'-benzylbenzohydrazide derivatives were designed and synthesized. The structures of the new compounds were characterized using (1)H nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), or electron impact mass spectrometry (EI-MS), and their biological activities at a concentration of 600 mg L(-1) were determined against cotton aphid (Aphis gossypii Glover), carmine spider mite (Tetranychus cinnabarinus), and diamondback moth (Plutella xylostella). The results of a preliminary assay showed that compounds 6a-I-2 and 6d-III-4 maintained the lethal activity of anthranilic diamide against P. xylostella; compounds 6c-II-4, 6d-I-7, 6d-II-1, and 6d-III-5 exhibited good lethal activity against A. gossypii; and compounds 6a-II-1, 6a-III-1, 6b-I-7, 6c-I-1, and 6c-III-5 retained promising larvicidal activities against T. cinnabarinus. In subsequent further tests against T. cinnabarinus, compounds 6a-II-1, 6a-III-1, 6c-I-1, and 6c-III-5 showed an LC(50) value of <90 mg L(-1); especially, the LC(50) of compound 6a-III-1 was only 27.9 mg L(-1). In conclusion, the introduction of the functional fragment-substituted acyl hydrazine improved the acaricidal activity of the anthranilic diamide skeleton, and the halogen atom at X position and the methyl group at R(1) play crucial roles in the biological activities of the compounds.

Synthesis, crystal structure and biological activity of novel anthranilic diamide insecticide containing alkyl ether group

In searching for environmentally benign insecticides with high activity, low toxicity and low residue, two series of novel anthranilic diamide containing methyl ether and isopropyl ether group were designed and synthesized. All of the compounds were characterized by (1)H NMR spectroscopy, (13)C NMR spectroscopy and elemental analysis. The single crystal structure of 19j was determined by X-ray diffraction. The insecticidal activities of the new compounds were evaluated. The results showed that some compounds exhibited excellent insecticidal activities against Lepidoptera pests. Among this series, compound, 18l showed 100 % larvicidal activity against Mythimna separate Walker, Plutella xylostella Linnaeus and Laphygma exigua Hubner at the test concentration, which was equal to the available chlorantraniliprole.

Design, synthesis, and analysis of the quantitative structure-activity relationships of 4-phenyl-acyl-substituted 3-(2,5-dimethylphenyl)-4-hydroxy-1-azaspiro[4.5]dec-3-ene-2,8-dione derivatives

A series of 4-phenyl-acyl-substituted 3-(2,5-dimethylphenyl)-4-hydroxy-1-azaspiro[4.5]dec-3-ene-2,8-dione derivatives were designed and synthesized, and their structures were characterized using (1)H NMR (or (13)C NMR), mass spectrometry, and elemental analysis. The bioactivities of the new compounds were evaluated. These compounds exhibited good inhibition activities against bean aphids (Aphis fabae) and carmine spider mite (Tetranychus cinnabarinus), and 4-phenyl acyl esters showed stronger bioactivity than 4-arylesterases and alkyl esters. The results showed that compound 8-I-e, which contains a para-methoxy group on the phenyl acyl, and compound 8-I-m, which contains a para-trifluoromethyl group on the phenyl acyl, displayed potent insecticidal activity against A. fabae and T. cinnabarinus respectively. The insecticidal activity showed a clear structure-activity relationship, confirming the importance of the flexible bridge. The DFT/B3LYP/6-31(d) level method was used to calculate molecular geometries and electronic descriptors. These factors included total energy, charge distribution, and the linear orbital level of the title compounds. Quantitative structure-activity relationship studies were performed on these compounds using quantum-chemical and physicochemical parameters as independent variables and insecticidal activity as a dependent variable. Insecticidal activity was most closely correlated (r > 0.8) with quantum chemical and physicochemical parameters.

Synthesis, biological evaluation and molecular docking studies of 1,3,4-oxadiazole derivatives as potential immunosuppressive agents

A series of 1,3,4-oxadiazole derivatives derived from 4-methoxysalicylic acid or 4-methylsalicylic acid (6a-6z) have been first synthesized for their potential immunosuppressive activity. Among them, compound 6z displayed the most potent biological activity against lymph node cells (inhibition=38.76% for lymph node cells and IC(50)=0.31 μM for PI3Kγ). The preliminary mechanism of compound 6z inhibition effects was also detected by flow cytometry (FCM) and the compound exerted immunosuppressive activity via inducing the apoptosis of activated lymph node cells in a dose dependent manner. Docking simulation was performed to position compound 6z into the PI3Kγ structure active site to determine the probable binding model.

Design, synthesis, and insecticidal activity of novel pyrazole derivatives containing α-hydroxymethyl-N-benzyl carboxamide, α-chloromethyl-N-benzyl carboxamide, and 4,5-dihydrooxazole moieties

On the basis of commercial insecticides tebufenpyrad and tolfenpyrad, two series of novel pyrazole-5-carboxamides containing α-hydroxymethyl-N-benzyl or α-chloromethyl-N-benzyl and pyrazoles containing 4,5-dihydrooxazole moieties were designed and synthesized via the key intermediate 2-amino-1-(4-substituted) phenyl ethanol. The structures of target compounds were confirmed by (1)H NMR and elemental analysis or high-resolution mass spectrum (HRMS), and their activities against cotton bollworm (Helicoverpa armigera), diamondback moth (Plutella xylostella), bean aphid (Aphis craccivora), mosquito (Culex pipiens pallens), and spider mite (Tetranychus cinnabarinus) were tested. The results of bioassays indicated that compounds containing α-chloromethyl-N-benzyl and compounds containing 4,5-dihydrooxazole showed high insecticidal activity against cotton bollworm. Especially, stomach activities of compounds Ij, Il, and IIe were 60% at 5 mg kg(-1). Moreover, the target compounds exhibited high selectivity between cotton bollworm and diamondback moth, although both of them belong to the order Lepidoptera. Although the activities against diamondback moth were at a low level, some of the target compounds exhibited antifeedant activity. The compounds also had good activities against bean aphid, mosquito, and spider mite. The foliar contact activity of compounds Ic, Id, Ie, and IIf against bean aphid were 95, 95, 100, and 95%, respectively, at 200 mg kg(-1). The miticidal and ovicidal activities of compound IIi against spider mite were both 95% at 200 mg kg(-1). Furthermore, a trivial change at 4-position of pyrazole ring would lead to great changes in properties and activities, which can easily be deduced by comparing the activities of compounds in series I (4-chloro-pyrazole compounds) with corresponding compounds in series II (4-hydro-pyrazole compounds), especially from the miticidal and ovicidal activities of Ii and IIi against spider mite.

Synthesis, Insecticidal Evaluation of Novel 1,3,4-Thiadiazole Chrysanthemamide Derivatives formed by an EDCI/HOBt Condensation

A series of novel pesticides with two components derived from a 1,3,4-thiadiazole and chrysanthemic acid were synthesised via an EDCI/HOBt condensation. These 1,3,4-thiadiazole chrysanthemamides were identified by IR, 1H NMR and elemental analyses. Their insecticidal activity was also evaluated.

Synthesis and insecticidal activities of novel 1,3,4-thiadiazole 5-fluorouracil acetamides derivatives: an RNA interference insecticide

A series of novel 1,3,4-thiadiazole 5-fluorouracil acetamides derivatives were designed and synthesized. Their structures were confirmed by infrared, (1)H NMR spectroscopy, and elemental analysis. The insecticidal activities against Tetranychus cinnabarinus and Aphis craccivora of these new compounds were evaluated. The bioassay tests showed that most of these title compounds possessed a good combination of stomach toxicity as well as contact toxicity against Tetranychus cinnabarinus and Aphis craccivora. In particular, the insecticidal activity of the title compound IVe against Aphis craccivora was better than the commercialized thiacloprid and was also comparable to another commercialized product, imidacloprid. The introduction of fluorines to meta and para-position of the benzene ring was essential for high bioactivity.

Novel 1,3,4-heterodiazole analogues: synthesis and in-vitro antitumor activity

The synthesis of some new heterodiazole and their annulated imidazo[2,1-b]1,3,4-oxa/thiadiazolone 6a-d, 7a-d; 1,3,4-oxa or thiadiazole[3,2-a]pyrimidine diamine 8a-d and 1,3,4-oxa or thiadiazole-3-piperidino-1-propamide 11a,b derivatives have been described. The obtained compounds were evaluated for their in-vitro antitumor activity. A single dose (10 μM) of the test compounds were used in the full National Cancer Institute (NCI) 60 cell lines panel assay. Compounds 6c and 6d displayed appreciable anticancer activity against leukemia, non-small cell lung, CNS and showed moderate activity against colon, melanoma, and breast cancer cells lines. Compound 6c possessed remarkable broad-spectrum antitumor activity which almost 4 fold more active than the known drug 5-FU with GI(50), TGI, and LC(50) values of 6.0, 17.4, and 55.1 μM, respectively.