Fenpirithrin was manufactured using the same multi step ester assembly strategy typical of synthetic pyrethroids. Its production centred on preparing two key fragments. Firstly, a cyclopropanecarboxylic acid derivative bearing the characteristic 2,2 dichlorovinyl and 2,2 dimethyl substituents, and secondly a cyano(6 phenoxy 2 pyridyl)methyl alcohol, produced through pyridyl phenoxy coupling and cyanohydrin formation. These intermediates were then esterified to form technical grade fenpirithrin, which was purified and formulated
