Patent ID: 6297386
Filing Date: 2001-10-02
Classification: C07D

Abstract:
A process for preparing 1-alkyl-pyrazole-5-carboxylic esters of the formula (I) ##STR4##whereinR.sup.1 and R.sup.4 independently of one another each represent straight-chain or branched C.sub.1 -C.sub.6 -alkyl, C.sub.3 -C.sub.7 -cycloalkyl or optionally substituted C.sub.7 -C.sub.12 -aralkyl andR.sup.2 and R.sup.3 independently represent hydrogen, straight-chain or branched C.sub.1 -C.sub.6 -alkyl, C.sub.3 -C.sub.7 -cycloalkyl, or optionally substituted C.sub.7 -C.sub.12 -aralkyl,comprising reacting(1) the enolate of a 2,4-diketocarboxylic ester of the formula (II) ##STR5##whereinR.sup.2, R.sup.3, and R.sup.4 are each as defined for formula (I) andM represents the equivalent of a metal atom, with(2) an N-alkylhydrazinium salt of the formula (III)R.sup.1 --NH.sub.2 --NH.sub.2.sup..sym. R.sup.5 COO.sup..crclbar. (III),whereinR.sup.1 is as defined in formula (I) andR.sup.5 together with the COO.sup..theta. moiety represents the anion of an organic acid, in the presence of a solvent and water, wherein the total amount of solvent plus water comprises from 10 to 60% by weight of water.