Diethyl dithiophosphoric acid is chlorinated to generate diethylthiophosphoryl chloride, which is then treated with sodium 4-nitrophenolate (the sodium salt of 4-nitrophenol).
Diethyl dithiophosphoric acid is chlorinated to generate diethylthiophosphoryl chloride. Diethylthiophosphoryl chloride is then treated with sodium 4-nitrophenolate (the sodium salt of 4-nitrophenol).