p-Toluenesulfonic acid → 3-Amino-4-n-butyl-1-(3,4-dichlorobenzyl)-pyrazol-5-one

Participants

Reaction Steps

To a solution of 41.1 g α-n-butyl-β-amino-β-ethoxyacrylic acid ethyl ester and a spatula tipfull of p-toluenesulphonic acid in 100 ml ethanol were added dropwise, under nitrogen, 36.5 g 3,4-dichlorobenzylhydrazine. After the mixture had been stirred afterwards for two hours, it was left to stand overnight. The solvent was distilled off, a mixture of ether/petroleum ether (1:1) was added to the residue; the product crystallized through.

Provenance & Evidence