| 摘要 |
<p>A process for the preparation of 3,5-disubsti-tuted pyrazoles useful as herbicides which involves: (a) the reaction of a methyl ketone, such as acetophenone or an appropriate derivative thereof, with an appropriate aldehyde, such as benzaldehyde in the presence of base to form a 1,3-disubstituted .alpha.,.beta.-unsaturated ketone, such as chalcone or a substituted chalcone; (b) the acidification of said .alpha.,.beta.-unsaturated ketone, followed by treatment of the acidified reaction mixture with hydrazine to form a disubstituted pyrazoline; and (c) the catalytic dehydrogenation of said pyrazoline to yield the desired 3,5-di-substituted pyrazole.</p> |
