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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 compound T27 was determined by single crystal X-ray diffraction. 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 μg/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(1 ha=104 m2) in the greenhouse 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-benzothiazine 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 further development of novel 2,1-benzothiazine-containing herbicides.

BACKGROUND Anthranilic diamide insecticides control lepidopteran pests through selectively binding and activating insect ryanodine receptors. In order to search for potential insecticides targeting the ryanodine receptors, a series of anthranilic diamide analogs including trifluoromethyl, nitro, or chloro groups were designed and synthesized by the principle of bioisosterism and structural optimization. RESULTS Insecticidal data indicated that some compounds displayed good activity against oriental armyworm (Mythimna separata) and diamondback moth (Plutella xylostella). In particular, the larvicidal activity of 6p against P. xylostella was 95% at 0.01 mg L-1 , equivalent to chlorantraniliprole (85%, 0.01 mg L-1 ). The comparative molecular similarity index analysis model obtained indicated that hydrogen bond acceptor and electron-withdrawing groups in the R'3 group are favourable for insecticidal activity against M. separata, which is consistent with the structure-activity relationships. Moreover, the calcium imaging experiment indicated, like chlorantraniliprole, that 6h and 6p are interacting with the ryanodine receptor. CONCLUSION Introducing trifluoromethyl, nitro, or chloro groups to a specific position in the N-phenylpyrazole could improve or maintain the activity against M. separata and P. xylostella. 6h and 6p could be used as potential lead compounds for ryanodine receptor modulators. © 2018 Society of Chemical Industry.

To further explore the structure-activity relationship(SAR) of amide bridge moeity of anthranilic diamides derivatives, a series of N-pyridylpyrazole derivatives was designed, synthesized and their biological activities were evaluated. The chemical structures of novel target compounds were confirmed by 1H nuclear magnetic resonance (NMR), 13C NMR and elemental analyses(EA). Bioassay results of insecticidal activity demonstrated that the target compound 6h displayed 70% lethality rate against oriental armyworms at 200 mg/L. Moreover, most compounds displayed moderate to excellent antifungicidal activities against Fusarium oxysporum f. sp. cucumerinum, Cercospora arachidicola Hori, Botryosphaeria dothidea, Alternaria solani, Gibberella zeae and Phytophthora capsici at 50 mg/L. In particular, compound 6e showed 61.5% and 92.3% inhibition rate against Cercospora arachidicola Hori and Botryosphaeria dothidea, which was superior to the commercial positive control Chlorothalonil. These results will provide a potential clue for exploring novel high-effective agrochemicals.

With the introduction of various heterocyclic rings at the benzene part of anthranilic diamides, a series of N-pyridylpyrazolecarboxamide derivatives containing isoxazole, isoxazoline and 1,3,4-thiadiazole rings was designed, synthesized and evaluated for their insecticidal activities. The structures of the obtained novel target compounds were confirmed by means of 1H NMR, 13C NMR and HRMS. The bioassay results indicated that most of the target compounds displayed moderate or good insecticidal activities against oriental armyworm and diamondback moth at the adopted concentrations compared with chlorantraniliprole, especially compounds Ii and Il, of which the LC50 and LC95 values against oriental armyworm were further measured. The structure-activity relationship demonstrated that the introduction of chlorine in benzene ring, bromomethyl and acetoxyl substituents in 4,5-dihydroisoxazole part was more advantageous to improve the corresponding insecticidal activities than the introduction of other substituents and heterocycles.

Three series of new anthranilic diamide derivatives containing sulfide, N-cyanomethylsulfilimine, and N-cyanomethylsulfoximine groups were designed and synthesized by combining the active substructures of anthranilic diamides and sulfoxaflor. The structures of all newly synthesized compounds were confirmed by IR and 1H/13C-NMR, and some of them were confirmed by elemental analysis or HRMS too. The synthesized compounds were screened for their insecticidal and fungicidal activities. Bioasssay results indicated that some of the synthesized compounds possessed certain degrees of insecticidal activity against Mythimna separata. However, some compounds exhibited good fungicidal activity against Sclerotinia sclerotiorum.

A series of novel 1,2,4-triazoles containing 1,2,3-thiadiazole derivatives were designed and synthesized. Their structures were confirmed by melting points, IR, 1 H NMR, and elemental analysis and ESI-MS or HRMS. Preliminary bioassays indicated that these compounds exhibited very good insecticidal activity against Aphis laburni at 100 μg/mL, with mortality no less than 95%. Compounds 6a , 6c , 6f , 6l showed higher curative activity against TMV and compound 6h showed a higher induction effects against TMV in vivo at 100 μg/mL. Collectively, our data demonstrate a new strategy for control of insects and viruses.

A series of novel coumarin derivatives containing sulfinic esters or sulfonamide were designed and synthesized. Their structures were characterized by H-1 NMR, C-13 NMR and elemental analysis. The preliminary bioassays indicated that several target compounds exhibited good in vitro antitumor activities on A549 (up to 67.82%), Be17402 (up to 58.47%) and HCT-8 (up to 74.80%) at 5.0 mg/L and moderate antifungal activities on Physalospora piricola (up to 82.0 %) at 50 mg/L. The structure-activity relationship of these target compounds was discussed accordingly.

Three series of new anthranilic diamide derivatives containing sulfide, N-cyanomethylsulfilimine, and N-cyanomethylsulfoximine groups were designed and synthesized by coupling the active substructures of anthranilic diamides and sulfoxaflor. The structures of the synthesized compounds were confirmed by infrared spectroscopy, 1H and 13C NMR, and elemental analysis. Several unique structural characteristics were revealed via the crystal structure analysis of compound N-(2-(2-methyl-2-(methylthio)propylcarbamoyl)-4-chloro-6-methylphenyl)-3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carboxamide 16e. Bioassay results indicated that most of the synthesized compounds showed superior insecticidal activities against Mythimna separata and Plutella xylostella when compared with the positive control cyantraniliprole. In particular, N-(2-(2-methyl-2-(N-cyanomethylsulfideimino)propylcarbamoyl)-4-chloro-6-methylphenyl)-3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carboxamide 17e showed excellent insecticidal activity against Mythimna separata, with a mortality rate of 100 % at a concentration of 1 µg mL–1. These results indicated that sulfide, N-cyanomethylsulfilimine, and N-cyanomethylsulfoximine moieties, as important active substructures, could improve or maintain the activity of the anthranilic diamide and promote novel pesticide development.