| 摘要 |
NEW MATERIAL:A compound of formula I (X is O, S; R is alkyl which is substituted with carboxyl or a group functionally derived therefrom). EXAMPLE:S-Etoxycarbonylmethyl 2-nitro-5-(2'-chloro-4'-trifluoromethylphenoxy) phenylthioacetate. USE:Selective herbicide: it can control selectively weeds in crop plants such as rice, cereals, cotton and so on with a small amount by pre- or post-emergence application. It causes no damage to crop plants and no injury to mammarians and fishes. PREPARATION:For example, the reaction between 3-(4'-trifluoromethylphenoxy)phenylacetyl halide of formula V (Y is halogen) and a compound of formula III' is carried out, if necessary, in an inert organic solvent, in the presence of an acid-binding agent such as triethylamine to give a compound of formula IV', which is nitrated with a nitrating agent such as copper nitrate to give the compound of formula I.
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