2,4-二氟苯甲酰基硫脲化合物的合成与除草活性研究

以2,4-二氟苯甲酸(化合物1)和2-氨基-4,6-二甲氧基嘧啶为原料,经氯化、酰化和加成反应合成了具有生物活性的2,4-二氟苯甲酰基硫脲化合物(4)。考察了反应物配比、反应时间等因素对反应的影响,用元素分析和 IR、~1H NMR 对其结构进行了表征。结果表明:n(氯化亚砜)/n(化合物1)=6∶1,回流反应8 h 得到2,4-二氟苯甲酰氯(化合物2),收率89%(质量分数);n(硫氰酸钾)/n(化合物2)=1∶1,乙腈为溶剂,回流反应1 h,得到2,4-二氟苯甲酰基异硫氰酸酯(化合物3)的乙腈溶液;n(化合物3)/n(2-氨基-4,6-二甲氧基嘧啶)=0.97∶1,加入反应物总质量3%的溴化四丁基铵作催化剂,回流反应4 h,得到化合物4,收率90%(质量分数)。经初步生物活性测试表明,化合物4具有一定的除草活性。

SYNTHESIS AND HERBICIDAL ACTIVITIES OF 2,4-DIFLUOROBENZOYLTHIOUREA COMPOUND

2,4-Difluorobenzoylthiourea was synthesized from 2,4-difluorobenzoic acid and 2-amino-4.6- dimethoxyl pyrimidine by chloration,acylation and addition.Its structure was characterized by IR. ~1H NMR and elemental analysis.The effects of the molar ratios of the reactants and the reaction time on the reaction were discussed.The results showed that when the molar ratio of thionyl chloride to 2, 4-difluorobenzoic acid was 6:1,refluxed for 8 h,the yield of 2,4-difluorobenzoyl chloride was 89%; the molar ratio of potassium thiocyanate to 2,4-difluorobenzoyl chloride was 1:1,using acetonitrile as solvent,refluxed for 1 h,the acetonitrile solution of 2,4-difluorobenzoyl isosulfocyanic ester was obtained;when the molar ratio of 2,4-difluorobenzoyl isosulfocyanic ester to 2-amino-4,6-dimethoxyl pyrimidine was 0.97:1,tetrabutyl ammonium bromide as catalyst with its quantity being 3% of the total mass of the reactants,refluxed for 4 h,the yield of 2,4-difluorobenzoylthiourea was 90%.The preliminary biological tests showed that this compound had good herbicidal activity.