申请人:FMC Corporation
                            
                            
                                公开号:US06268506B1
                            
                            
                                公开(公告)日:2001-07-31
                            
                            A process for preparing an alkyl &agr;-2-chloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-2,4-substituted-benzene-propanoate herbicide, by reacting an alkyl &agr;-acetyl-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-2,4-disubstituted-benzene-propanoate, Intermediate D, first with sodium hypochlorite, then with a base, and recovering the herbicide. Intermediate D is prepared by reacting a 1-(2,4-disubstituted-5-halophenyl)-4-difluoromethyl-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazole, Intermediate B, with an alkyl alkanoate in the presence of a palladium catalyst and a tertiary amine. Intermediate B is prepared by reacting a 1-(2,4-disubstituted-phenyl)-4-difluoromethyl-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazole with a halogenating agent in the presence of an acid. The 2,4-substituents are independently selected from halo, alkyl, cycloalkyl, alkoxy, nitro, or hetercyclyl.
                            一种制备烷基α-2-
氯-5-[4-(二
氟甲基)-4,5-二氢-3-甲基-5-氧代-
1H-1,2,4-三唑-1-基]-2,4-取代
苯丙酸酯
除草剂的方法,通过将烷基α-乙酰基-5-[4-(二
氟甲基)-4,5-二氢-3-甲基-5-氧代-
1H-1,2,4-三唑-1-基]-2,4-二取代
苯丙酸酯(中间体D)先与
次氯酸钠反应,然后与碱反应,并回收
除草剂。中间体D是通过在
钯催化剂和三级胺存在下,将1-(2,4-二取代-5-卤代苯基)-4-二
氟甲基-4,5-二氢-3-甲基-5-氧代-
1H-1,2,4-三唑(中间体B)与烷基酸酯反应制备的。中间体B是通过在酸的存在下,将1-(2,4-二取代苯基)-4-二
氟甲基-4,5-二氢-3-甲基-5-氧代-
1H-1,2,4-三唑与卤代试剂反应制备的。2,4-取代基独立地选择自卤代、烷基、环烷基、烷氧基、硝基或杂环基。