Boron Trichloride → ethyl 1-methyl-1H-pyrazole-4-carboxylate

Participants

Reaction Steps

To a solution of 20.1 g of 3-[4-chloro-2-(2-fluoro-α-methoxy-benzyl)-phenyl]-4-ethoxycarbonyl-2-methyl-pyrazole in 250 ml methylene chloride is added 54 ml of a 1.4 molar boron trichloride solution in methylene chloride, and the mixture is stirred during 16 hours. Ice/water is then added; the organic layer separated, washed with a saturated solution of sodium chloride and dried over anhydrous sodium sulfate. The aqueous layers are reextracted with methylene chloride. After removal of the solvent, the 3-[4-chloro-2-fluoro-benzyl)-phenyl]-4-ethoxycarbonyl-2-methyl-pyrazole is obtained as the solid residue, which is directly used in the next step.

Provenance & Evidence