Synthesis and acaricidal activity of strobilurin-pyrimidine derivatives

Pyriminostrobin, a new acaricide, was discovered in our previous studies. Because introducing fluorine into organic compounds can increase bioactivity, pyriminostrobin was modified as a series of strobilurin-pyrimidine derivatives for biological screening. The compounds were characterized by 1H NMR, MS and elemental analysis. Preliminary bioassays demonstrated that compounds 7e and 7i exhibited significant control against Tetranychus cinnabarinus （Boisd.） at 0.625 mg L^-1, and their acaricidal potencies were higher than pyriminostrobin in a greenhouse. The relationship between structure and acaricidal activity was also studied.

Synthesis and Antifungal Activities of Novel Strobilurin Derivatives Containing Quinolin-2（1H）-one Moiety

To discover novel lead compounds with better antifungal activities, a series of novel strobilurin derivatives containing quinolin-2（1H）-one moiety was designed and synthesized via intermediate derivatization method. Their structures were characterized by means of 1H nuclear magnetic resonance（IH NMR）, 13C NMR and high reso- lution mass spectrometry（HRMS）. The biological assay results indicate that most target compounds exhibit good to excellent fungicidal activities against 10 plant pathogens. Compounds 4d, 5b and 5c possess 94.1%, 83.8% and 80.9% in vitro inhibition respectively against Rhizotonia cereals at the concentration of 50 μg/mL, which are better than that of the control agents. Especially, the inhibition activities of compound 4d against all of the tested fungi approach or exceed those of the controls. The structure-activity relationship was also discussed.

Design, synthesis, and fungicidal activity of novel 1,3,4-oxadiazole derivatives

Employing the intermediate derivatization method（IDM）, twenty novel 1,3,4-oxadiazole derivatives containing arylpyrazoloxyl moiety were designed and synthesized. The structures of the title compounds were identified by1 H NMR,13 C NMR, MS and elemental analyses, compound 4 was further identified by single-crystal X-ray diffraction. Antifungal activities against rice sheath blight（RSB） and sorghum anthracnose（SA） were evaluated by the mycelium linear growth rate method. Compounds 4, 16 and 20 displayed significant activities against RSB（EC50= 0.88 mg/L, 0.91 mg/L and 0.85 mg/L, respectively）,higher than the reference tebuconazole; While compound 3 exhibited higher activity against SA（EC50= 1.03 mg/L）, equal to commercial pyraclostrobin（EC50= 1.06 mg/L）. The study showed that compound 20 is a promising fungicide for further development.

Synthesis and bioactivity of novel coumarin derivatives containing(E)-methyl 2-(methoxyimino)-2-phenylacetates

Ten coumarin derivatives containing（E）-methyl 2-（methoxyimino）-2-phenylacetate were synthesized and bioassayed.The compounds were identified by IR,~1H NMR and elemental analyses.The test results indicated that compound 5j（R^1 is methyl and R^2 is n-C_6H_（13）） was the optimal structure in this paper with good fungicidal activity against CDM（85%） at 6.25 mg/L concentration.