176729-01-4

Upstream product

• 176728-86-2 Methyl α-[1,3-dimethyl-4-(2,5-dichlorobenzyloxy)-1H-pyrazol-5-yl]-acetate 
• 544-16-1 n-Butyl nitrite 
• 865-47-4 potassium tert-butylate 

Downstream Products

• 176728-87-3 N-methyl α-[1,3-dimethyl-4-(2,5-dichlorobenzyloxy)-1H-pyrazol-5-yl]-α-methoximino acetamide 

Relevant academic research and scientific papers

Intermediates for pyrazolyl acetic acid derivatives

The invention discloses a novel process for the preparation of a compound of formula II STR1 wherein R1 is C1-5 alkyl, R2 is hydrogen or C1-5 alkyl, and R3 is optionally substituted phenyl, comprising the reaction of a 4-hydroxypyrazole of formula III STR2 wherein R1 and R2 are as defined for formula II, with a benzylhalide of formula IV wherein Hal is halogen, preferably bromine or chlorine, and R3 is as defined for formula II, in the presence of a base. The invention further comprises a novel process for the preparation of the 4-hydroxypyrazole of formula III. The compounds of formulae II and III are intermediates for highly effective systemic fungicides of the class of pyrazolyl acetic acid derivatives.