Intermediates for pyrazolyl acetic acid derivatives

Abstract

The invention discloses a novel process for the preparation of a compound of formula II ##STR1## wherein R.sub.1 is C.sub.1-5 alkyl, R.sub.2 is hydrogen or C.sub.1-5 alkyl, and R.sub.3 is optionally substituted phenyl, comprising the reaction of a 4-hydroxypyrazole of formula III ##STR2## wherein R.sub.1 and R.sub.2 are as defined for formula II, with a benzylhalide of formula IV Hal--CH.sub.2 --R.sub.3 (IV) wherein Hal is halogen, preferably bromine or chlorine, and R.sub.3 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.

Dependencies are inferred from the claim text.