Design, synthesis and fungicidal evaluation of novel psoralen derivatives containing sulfonohydrazide or acylthiourea moiety.

To search a novel lead structure for antiphytopathogenic fungus agent, a series of novel psoralen derivatives possessing sulfonohydrazide or acylthiourea structure were designed and synthesized, and their fungicidal activity against seven phytopathogens was evaluated. Their structures were confirmed by melting points, 1H NMR, 13C NMR and HRMS, and the typical crystal structure was determined by X-ray diffraction for validation. Preliminary fungicidal activity showed that some of the title compounds exhibited certain-to-high fungicidal activity. Compound I-13 exhibited good fungicidal activity against Botrytis cinerea, Cercospora arachidicola and Physalospora piricola with EC50 values of 12.49, 13.22 and 12.12 µg/mL, respectively. Compounds II-9 and II-15 showed over 90% inhibition against B. cinerea at 50 µg/mL in vitro. In particular, II-9 exhibited significant higher fungicidal activity with a lower EC50 value of 9.09 µg/mL than the positive control YZK-C22 (13.41 µg/mL). Our studies found that sulfonohydrazide or acylthiourea-containing psoralen derivatives were promising fungicide leads deserve for further study.

Anthranilic diamides derivatives as potential ryanodine receptor modulators: Synthesis, biological evaluation and structure activity relationship.

A series of novel anthranilic diamides derivatives (7a-s) containing halogen, trifluoromethyl group and cyano group were designed, synthesized, and characterized by melting point, 1H NMR, 13C NMR and elemental analyses. The bioactivity revealed that most of them showed moderate to excellent activities against oriental armyworm (Mythimna separata) and diamondback moth (Plutella xylostella). Above all, the larvicidal activity of 7o against oriental armyworm was 100% and 40% at 0.25 and 0.1 mg L-1, comparable to that of the standard chlorantraniliprole (100%, 0.25 mg L-1 and 20%, 0.1 mg L-1). What is more, 7o against diamondback moth displayed 90% insecticidal activity at 0.01 mg L-1, superior to chlorantraniliprole (45%, 0.01 mg L-1). The experiments 7o on the American cockroach (Periplaneta Americana) heart beating rates (Dorsal vessel) and contractile force were compared with chlorantraniliprole. In addition, 7o could affect the calcium homeostasis in the central neurons of the third larvae of oriental armyworm, which revealed that the ryanodine receptor is the potential target of 7o. The density functional theory (DFT) calculation results revealed the amide bridge, the benzene ring of anthraniloyl moiety and pyrazole ring might play an important role in the insecticidal activity through hydrophobic interactions and π-π conjugations.

Design, Synthesis, and Biological Evaluation of Novel Psoralen-Based 1,3,4-Oxadiazoles as Potent Fungicide Candidates Targeting Pyruvate Kinase.

Pyruvate kinase (PK) has been considered as a promising fungicide target discovered in our previous studies. Natural compounds are important sources for discovery and development of new pesticides. To continue our ongoing studies on the discovery of novel PK-targeted fungicides, a series of novel psoralen derivatives including a 1,3,4-oxadiazole moiety were designed by a computer-aided pesticide molecular design method, synthesized, and evaluated for their fungicidal activity. The bioassay results indicated that compounds 11d, 11e, 11g, 11i, and 12a showed excellent in vitro fungicidal activity against Botrytis cinerea with EC50 values of 4.8, 3.3, 6.3, 5.4, and 3.9 µg/mL, respectively. They were more active than the corresponding positive control YZK-C22 [3-(4-methyl-1,2,3-thiadiazol-5-yl)-6-(trichloromethyl)-[1,2,4]-triazolo-[3,4-b][1,3,4]-thiadiazole] (with an EC50 value of 13.4 µg/mL). Compounds 11g and 11i displayed promising in vivo fungicidal activity against B. cinerea with 80 and 70% inhibition at a concentration of 200 µg/mL, respectively. They possessed much higher fungicidal activity than the positive control psoralen and comparable activity with the positive control pyrisoxazole. Enzymatic assays indicated that 11i showed good BcPK inhibition with an IC50 value of 39.6 µmol/L, comparable to the positive control YZK-C22 (32.4 µmol/L). Molecular docking provided a possible binding mode of 11i in the BcPK active site. Our studies suggested that the psoralen-based 1,3,4-oxadiazole 11i could be used as a new fungicidal lead targeting PK for further structural optimization.