棉田除草剂溴嘧氯草醚的中试合成及杂质鉴定

为研究棉田除草剂溴嘧氯草醚(开发代号SIOC0426,化学名称为N-2-氯-6-(4,6-二甲氧基-2-嘧啶氧基)苄基]-4-溴苯胺)的中试合成工艺,以2-氟-6-氯苯甲醛为起始原料,通过水解、缩合、还原和亲核取代反应在公斤级规模上合成了溴嘧氯草醚,用高效液相色谱外标法测定了原药含量,通过三维高效液相色谱-质谱联用(HPLC-DAD-MS)技术对原药中的杂质结构进行了鉴定。结果表明,反应总收率高于80%,原药含量大于98%,主要杂质为未反应完全的中间体2-(4-溴苯氨基)甲基]-3-氯苯酚和溴嘧氯草醚Smiles重排产物。该工艺反应条件温和,反应收率高,原药含量高,"三废"排放较少,较适合工业化放大生产。

Pilot-scale synthesis and impurities identification of cotton herbicide SIOC0426

Cotton herbicide SIOC0426 (4-bromo-N-(2-chloro-6-(4,6-dimethoxypyrimidin-2-yloxy)benzyl)aniline) was synthesized in kilo-scale from 2-chloro-6-fluorobenzaldehyde via hydrolysis, condensation, reduction and nucleophilic substitution reactions. The purity of the herbicide was determined by HPLC external standard method, and the impurities of the herbicide were elucidated by HPLC-DAD-MS. The four-step yield is above 80%, and the purity of the final product is greater than 98%. The impurities are unreacted intermediate 2-((4-bromophenylamino)methyl)-3-chlorophenol and Smiles rearrangement product of SIOC0426 . The pilot-scale synthetic method with the advantage of mild conditions, high yield, high purity and less wastes is suitable for industrial scale-up.