Ammonium Chloride → alpha-(1-Methylpyrazol-5-yl)-2,3-dichloro-4,5-dimethoxybenzylalcohol

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Reaction Steps

18 ml of 1.6M n-butyl lithium in n-hexane is added dropwise to a solution of 2.26 g of 1-methyl-pyrazole in tetrahydrofuran at -60° C. under argon gas atmosphere and the mixture is stirred at the same temperature for 1 hour. A solution of 5.88 g of 2,3-dichloro-4,5-dimethoxybenzaldehyde in tetrahydrofuran is added dropwise to the mixture at -60° to -50° C. and the mixture is stirred at -50° C. to room temperature for 1 hour. An aqueous ammonium chloride solution is added to the reaction mixture and the mixture is concentrated to remove organic solvent. The residue is extracted with ethyl acetate, and the extract is washed, dried and evaporated to remove solvent. The residue is crystallized from isopropyl ether to give 7.18 g of α-(1-methylpyrazol-5-yl)-2,3-dichloro-4,5-dimethoxybenzylalcohol.

Provenance & Evidence