NEW MATERIAL:A compound of formulaI(R is 1-3C lower alkyl). EXAMPLE:4-(4-Chloro-2-fluoro-5-methoxyphenyl)-1,2-tetramethyleneurazole. USE:Herbicide: it has much more powerful herbicidal activity compared with known analogous compounds and the pre-emergence or post-emergence application of a low dose of the compound to annual and perennial weeds develops extremely high herbicidal effects. PREPARATION:The reaction between a 4-phenylurazole derivative of formula II (M is alkali metal) and a dihalobutane of formula III (X is Br, Cl) is conducted in an aprotonic polar solvent such as DMF, when necessary, with heating to give the compound of formulaI.
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