The present invention relates to a new and efficient process for preparing 5-amino-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-(trifluoromethylthio)-IH-pyrazole-3-carbonitrile (hereinafter referred to as compound of formula I), which is useful as an intermediate for the antiparasitic agent fipronil, and a process for preparing 5-amino-3-cyano-l-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethyl sulfinylpyrazole (hereinafter referred to as compound of formula II or fipronil). In one aspect, there is provided a process for preparing fipronil comprising: a) a step of reacting CF3S(=O)ONa with the compound of formula (III) in the presence of a reducing/halogenating agent; and b) a step of oxidizing the compound of formula (I) obtained in step a) in the presence of a selective oxidizing agent, under suitable conditions, wherein the selective oxidizing agent selectively effects oxidation of (I) to the corresponding sulfoxide, Fipronil. In certain exemplary embodiments, the selective oxidizing agent is MHSO5, wherein M is an alkaline metal cation.
本发明涉及一种新的高效制备5-
氨基-1-(2,6-二
氯-4-(三
氟甲基)苯基)-4-(三
氟甲基
硫基)-IH-
吡唑-3-碳腈(以下简称为式I化合物)的过程,该过程可作为
杀虫剂非普罗尼尔的中间体,并提供一种制备5-
氨基-3-
氰基-1-(2,6-二
氯-4-三
氟甲基苯基)-4-三
氟甲基亚砜基
吡唑(以下简称为式II化合物或非普罗尼尔)的过程。在一个方面,提供了一种制备非普罗尼尔的过程,包括:a)在还原/卤化剂存在下,将
CF3S(=O)ONa与式(III)化合物反应的步骤;和b)在适当条件下,在选择性氧化剂存在下,氧化步骤a)中得到的式(I)化合物,其中选择性氧化剂选择性氧化(I)为相应的亚砜,即非普罗尼尔。在某些示例实施中,选择性氧化剂为
MHSO5,其中M为碱性
金属阳离子。