diuron

DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is an algicide and herbicide of the aryl urea class that inhibits photosynthesis. It was introduced by Bayer in 1954 under the trade name of Diuron. ==History== In 1952, chemists at E. I. du Pont de Nemours and Company patented a series of aryl urea derivatives as herbicides. Several compounds covered by this patent were commercialized as herbicides: chlortoluron (3-chloro-4-methylphenyl) and DCMU, the (3,4-dichlorophenyl) example. Subsequently, over thirty related urea analogs with the same mechanism of action reached the market worldwide. ==Synthesis== As described in the du Pont patent, the starting material is 3,4-dichloroaniline, which is treated with phosgene to form a isocyanate derivative. This is subsequently reacted with dimethylamine to give the final product. Aryl-NH2 + COCl2 → Aryl-NCO Aryl-NCO + NH(CH3)2 → Aryl-NHCON(CH3)2

==Mechanism of action== DCMU is a very specific and sensitive inhibitor of photosynthesis. It blocks the QB plastoquinone binding site of photosystem II, disallowing the electron flow from photosystem II to plastoquinone. This interrupts the photosynthetic electron transport chain in photosynthesis and thus reduces the ability of the plant to turn light energy into chemical energy (ATP and reductant potential).