| 摘要 |
PURPOSE: To obtain a pyrazole derivative, useful as a herbicide, nontoxic to useful crops and capable of selectively controlling gramineous and broad-leaved weeds in a small dose without requiring complicated steps. CONSTITUTION: This derivative of formula I [R<1> is H or a 1-4C alkyl; R<2> is a 1-4C alkyl; X<1> , X<2> , X<3> and X<4> are each independently a 1-4C alkyl; X<5> is a halogen; n is 0, 1 or 2] is obtained by reacting a nuclear halogen compound of formula II and a pyrazole compound of formula III with CO in the presence of a base and a metallic catalyst. The reaction is preferably carried out in a solvent such as 1,4-dioxane at 50-180 deg.C reactional temperature under 50-150kg/cm<2> pressure of CO for 1-100hr by adding palladium as the metallic catalyst in an amount of 0.05-0.5 based on the compound of formula II and triethylamine as the base in an amount of 1.0-10.0 equiv. based on the compound of formula II. |
