Method for producing 2-dihaloacyl-3-amino-acrylic acid esters and 3-dihalomethyl pyrazole-4-carboxylic acid esters
View Patent ↗The present invention relates to a process for preparing 2-dihaloacyl-3-aminoacrylic esters of the formula (I) by reacting acid halides of the formula (II) with dialkylaminoacrylic esters of the formula (III) in which R, R 1 , R 2 , X 1 , X 2 and Hal are each as defined in the disclosure in a water-immiscible organic solvent in the presence of a base, to the novel 2-dihaloacyl-3-aminoacrylic esters of the formula (I) themselves, to their use for preparing 3-dihalomethylpyrazoles, to a process for preparing 3-dihalo-methylpyrazoles, and to novel 3-dihalomethylpyrazoles.
1. A process for preparing 2-dihaloacyl-3-aminoacrylic esters of formula (I)
in which
R, R 1 , and R 2 are each independently C 1 -C 4 -alkyl, and
X 1 and X 2 are each independently fluorine, chlorine, or bromine, comprising reacting an acid halide of formula (II)
in which
Hal is fluorine, chlorine, or bromine, and
X 1 and X 2 are each independently fluorine, chlorine, or bromine, with a dialkylaminoacrylic ester of formula (III)
in which R, R 1 , and R 2 are each as defined for formula (I), in a water-immiscible organic solvent in the presence of a base, wherein the base is an inorganic aqueous base, pyridine, or a pyridine derivative.
2. A process according to claim 1 wherein the base is pyridine, picoline, 2-methyl-5-ethylpyridine, 2,4,6-collidine, quinoline, or quinaldine.