The crystal structure of the title compound（C24H24N2O5, Mr = 420.45） has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P1 with a = 8.991（1）, b = 11.166（1）, c = 11.169（1） , α = 91.413（2）, β = 105.887（2）, γ = 90.992（2）°, V = 1077.8（2） 3, Z = 2, Dc = 1.296 g/cm^3, F（000） = 444, μ（MoKα） = 0.091 mm^-1, the final R = 0.0466 and wR = 0.1507 for 4185 observed reflections（I 〉 2σ（I））. The single-crystal X-ray diffraction data indicated intermolecular C（17）–H（17）O（4）, C（5）–H（5）… O（4） hydrogen bonds and C–H…π interaction in the structure.
In order to find novel protoporphyrinogen oxidase inhibitors with high efficacy, broad-spectrum activity, and safety to crops, nine title compounds（4a-4i） were designed and synthesized by introducing pyrimidine moiety into the uracil skeleton with commercially herbicide butafenacil as the lead compound. Their structures were con- firmed by 1H NMR, IR, mass spectroscopy and elemental analysis. The bioassay results indicate that most of com- pounds 4 tested exhibit good to excellent herbicidal activities against B. campestris, A. retroflexus, E. crusgalli and D. sanguinalis in pre-emergence treatment at a dose of 1.5 kg/ha（1 ha=10^4 m^2）, for example, compound 4i showed 100% inhibition against the four plants tested in pre-emergence treatment at a dose of 1.5 kg/ha. So, this type of skeleton can be used as a valuable lead compound for the further development of a pre-emergent herbicide.
HE Leien WU Yingying ZHANG Hanyun LIU Manyun SHI Deqing
以4,6-二甲氧基嘧啶砜、水杨醛等为起始原料,依次经过亲核取代反应和氨基硫脲的缩合、环化,与异氰酸酯的加成反应合成了8个未见文献报道的含嘧啶和1,3,4-噻二唑的脲类化合物(3a^3h);目标化合物的结构经1 H NMR,IR,MS和元素分析确证.初步的除草活性测试结果表明,部分目标化合物在100mg/L时对油菜显示出中等的除草活性.
The crystal structure of the title compound（C24H22N2O5, Mr = 418.44） has been determined by single-crystal X-ray diffraction. The crystal is of orthorhombic, space group P21/c with a = 7.751（2）, b = 12.392（4）, c = 21.326（6）, V = 2048.4（1）3, Z = 4, Dc = 1.357 g/cm3, F（000） = 880, μ（MoKα） = 0.096 mm-1, the final R = 0.0731 and wR = 0.1982 for 3335 observed reflections（I 〉 2σ（I））. Intermolecular C（24）–H（24B）···O（1） hydrogen bond is observed in the structure.
