Process for the preparation of 1 - - 4 - nitro - pirazois aril, the herbicides to combat weeds and processes for the preparation of the

摘要

Novel 1-aryl-4-nitro-pyrazoles which exhibit herbicidal and plant growth-regulating activity of the formula IMAGE in which R1 represents in each case optionally substituted alkyl, alkenyl, alkinyl or cycloalkyl and R2 represents hydrogen, or represents in each case optionally substituted alkyl, alkenyl, alkinyl or cycloalkyl, or represents a radical IMAGE or R1 and R2, together with the nitrogen atom to which they are bonded, represent a saturated heterocyclic radical, which can optionally contain further hetero atoms, and Ar represents in each case optionally substituted phenyl or pyridyl, wherein X represents oxygen or sulphur and R3 represents hydrogen, alkyl, alkoxy, alkoxy-alkyl, alkylthio, alkylthioalkyl, alkylamino, di-alkylamino, halogenoalkyl, alkenyl or alkinyl, or represents optionally substituted cycloalkyl, or represents optionally substituted aryl, or represents optionally substituted aryloxy, or represents optionally substituted arylthio, or represents optionally substituted arylamino, but wherein R2 only represents hydrogen or a radical IMAGE if R1 does not simultaneously represent unsubstituted alkyl or represent alkyl which is substituted by an alkoximino radical.