Process for the in-situ preparation of fipronil, an insecticide and antiparasitic agent via thia-fries rearrangement

摘要

The invention relates to a novel in-situ process involving sulfinylation of a heterocyclic compound with sodium trifluoromethane sulfinate and by using stoichiometric quantity of thionyl chloride to produce Fipronil, an insecticide and antiparasitic agent and the process effectively minimizes the undesirable formation of the major impurity i.e. fipronil sulfide which would be difficult to get it separated from the end product.