Preparation of 2-haloacyl-3-amino-acrylic acid ester preparation, for use as intermediates for drugs and/or agrochemicals, from N-substituted 3-amino-acrylic acid ester and haloalkanoic acid anhydride

摘要

Preparation of 2-haloacyl-3-amino-acrylic acid esters (I) involves reacting N-substituted 3-amino-acrylic acid esters (II) with haloalkanoic acid anhydrides (III) in presence of a base. Independent claims are also included for: (1) the preparation of 3-haloalkyl-4-pyrazole-carboxylic acid esters (IV) by preparing (I) from (II) and (III), and then reacting (I) with hydrazines (V); and (2) the preparation of 3-haloalkyl-4-pyrazole-carboxylic acids (or their salts) (VI) by preparing (IV), then saponifying (IV) with acid or alkali.