bifenox

Bifenox is the ISO common name for an organic compound used as an herbicide. It acts by inhibiting the enzyme protoporphyrinogen oxidase which is necessary for chlorophyll synthesis.

==History== The nitrophenyl ethers are a well-known class of herbicides, the oldest member of which was nitrofen, invented by Rohm & Haas and first registered for sale in 1964. This area of chemistry became very competitive, with the Mobil Oil Corporation's filing in 1969 and grant in 1974 of a patent to the structural analog with a COOCH3 group adjacent to the nitro group of nitrofen. Bifenox was launched with the brand name Modown in 1981. Meanwhile Rohm & Haas had patented and developed acifluorfen (as its sodium salt with brand name Blazer) in 1980. Both compounds had much improved properties including a wider spectrum of herbicidal effect and good safety to some crops, including soybean. ==Synthesis== Bifenox was first synthesized by R.J. Theissen of the agricultural research section of Mobil Chemical's Central Research Laboratory in 1969 .thumb|centre|650px|Final step in the synthesis of bifenox The preparation of bifenox first described in the Mobil patent includes as its final step an Ullmann condensation between the potassium salt of 2,4-dichlorophenol and methyl 2-nitro-5-chlorobenzoic acid.