| 摘要 |
NEW MATERIAL:A compound shown by formula I (R is 2-3C alkyl; X is 1-3C alkyl or halogen; Y is H, 1-2C alkyl or halogen) and a salt thereof. EXAMPLE:1-Ethyl-4-(2-chloro-3-methyl-4-methanesulfonylbenzoyl)-5--hydr oxypyraz ole. USE:A selective herbicide having selectivity for maize and wheat. PREPARATION:A 1-substituted-5-hydroxypyrazole shown by formula II is reacted with a substituent group-containing benzoic acid shown by formula III In the presence of both N,N'-dicyclohexylcarbodiimide and a base (e.g. K2CO3) in a solvent such as t-butyl alcohol at 50-100 deg.C to give a compound shown by formula I or the compound shown by formula II is reacted with a compound shown by formula IV in an inert solvent in the presence of a dehydrochlorinating agent at room temperature - 100 deg.C to give a compound shown by formula V, which is rearranged to give the compound shown by formula I.
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