Preparation of substituted 3-aryl-5-haloalkyl-pyrazoles having herbicidal activity

A process for preparing a compound of Formula IIId, ##STR110## comprising condensing a phenyl-diketone of Formula IIIb ##STR111## with hydrazine in a reaction mixture comprising a solvent for said phenyl-diketone to form an alkyl-pyrazole-precursor intermediate, hydrazine being present in the reaction mixture in a stoichiometric excess amount relative to the phenyl-diketone, the amount of excess hydrazine being at least about 15 mole percent of a reference amount, the reference amount being the sum of the molar amount of unreacted phenyl-diketone and the molar amount of intermediate formed,

• removing the excess hydrazine from the reaction mixture leaving said intermediate in said solvent, and
• without recovering said intermediate from said solvent alkylating the intermediate with an alkylating agent, wherein:
• Ar is phenyl or substituted phenyl;
• R.sup.1 is alkyl or alkyl substituted with halogen, amino, nitro, cyano, hydroxy, carboxy, alkoxy, thio, mercaptoalkyl or alkylthio;
• and R.sup.2 is alkyl, hydroxy, alkoxy, acyl, carboxylic acid and aldehyde, amide and ester derivatives thereof, halogen, haloalkyl, amino, nitro, cyano, mercaptoalkyl, alkylthio, alkylsulfinyl, alkylsulfonyl, alkylphosphinyl or alkylphosphonyl.