Ethyl 4,5-dichloro-6-(1-methyl-5-pyrazolylcarbonyl)-1,3-benzodioxole-2-carboxylate → Ethyl 4,5-dichloro-6-(1-methyl-4-bromo-5-pyrazolylcarbonyl)-1,3-benzodioxole-2-carboxylate

Participants

Reaction Steps

A solution of 1.53 g of sodium bromate trihydrate in 5 ml of water is added to a solution of 2.0 g of ethyl 4,5-dichloro-6-(1-methyl-5-pyrazolylcarbonyl)-1,3-benzodi oxole-2-carboxylate in 20 ml of acetic acid at room temperature. The mixture is stirred at the same temperature for 15 hours. The reaction mixture is concentrated under reduced pressure to remove acetic acid. The residue is neutralized by addition of an aqueous saturated sodium bicarbonate solution and extracted with ethyl acetate. The extract is washed with water, dried and evaporated to remove solvent. The residue is purified by silica gel column chromatography (solvent; n-hexane-ethyl acetate) to give 1.0 g of ethyl 4,5-dichloro-6-(1-methyl-4-bromo-5-pyrazolylcarbonyl)-1,3-benzodioxol e-2-carboxylate as an oil.

Provenance & Evidence