In order to understand the composition and structure of herbicidal active substance from the root of Flaveria bidentis （L.） Kuntze, the isolation and structural identification were researched in this paper. The crude extract from the root ofF. bidentis （L.） Kuntze was extracted by petroleum ether, ethyl acetate, and water saturation of n-butyl alcohol, respectively, and the extraction fluid was separated by using the method of TLC, then the main fraction was separated by HPLC, and the structure of the herbicidal active substance was analyzed by LC-MS, elemental analysis and ~H-NMR. The results showed that the petroleum extraction had the strongest herbicidal activity, and the purple blue stripe separated by TLC had the strongest effect on Digitaria sanguinalis. The herbicidal active substance was identified as ct-terthienyl according to the data of LC-MS, elemental analysis and 1H-NMR.
HUO Jing-qianXING Ji-hongZHANG Li-huiKANG Zhan-haiZHANG Jin-lin
A strain of Bacillus subtilis strain YB 1, isolated and preserved in our lab., showed a high nicosulfuron-degrading activity. Optimization of culture conditions on production of nicosulfuron-degrading enzyme from Bacillus subtilis strain YB 1 was carried out through mono-factor experiments. The characterization of degrading enzyme（s） was studied in this paper. The results showed that B. subtilis YB1 can use nicosulfuron as sole carbon source under aerobic condition. The key enzyme（s） involved in the initial biodegradation of nicosulfuron was localized to extracellular proteins and showed to be induced expressed. Enzyme-specific activity was up to 89.34 U mg-1 at pH 8.0 and 30℃, incubation for 96 h, inoculum 4.5x108 CFU mL-1 in Luria-Bertani liquid medium with nicosulfuron of 40 mg L-1. The maximum degradation rate of extracellular crude enzymes on nicosulfuron was 66% at pH 9.0, 35℃ in the enzymatic reaction system with nicosulfuron of 5 mg L-1. This degrading enzyme（s） was sensitive to high temperature, but kept high activity under alkaline conditions.
The title compound 2-（（2,2-dimethyl-2,3-dihydrobenzofuran-7-yl）oxy）-N-（3-（furan-2-yl）-1-phenyl-1H-pyrazol-5-yl） acetamide（C25H23N3O4, Mr = 429.46） has been synthesized, and its structure was characterized by 1H-NMR, 13C-NMR, H RMS, and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 20.6205（18）, b = 5.2930（5）, c = 18.9282（17） A, β = 94.089（2）°, V = 2060.6（3） A^3, Z = 4, Dc = 1.384 g/cm^3, μ（Mo Ka） = 0.71073 mm^-1, F（000） = 904, R = 0.0345 and w R = 0.0930. The intramolecular hydrogen bond at N（1）–H（1）…O（2）, intermolecular weak interactions at O（3）…H（4） and weak π-π interactions connected the molecules to lead to one-dimensional tapes. Bioassay results indicated that the title compound had moderate herbicidal and fungicidal activities.
