2-Chlorobenzaldehyde → o-Chlorobenzaldoxime

Participants

Reaction Steps

To a stirred solution of 56.2 grams (0.40 mole) of 2-chlorobenzaldehyde and 55.6 grams (0.80 mole) of hydroxylamine hydrochloride in 225 ml of ethanol and 111 ml of water was added in portions over a 15 minute period a solution of 24.0 grams (0.60 mole) of sodium hydroxide in 24 ml of water. The addition caused a solid precipitate to form. The reaction mixture was heated to boiling, and water was added until the solid dissolved. Additional water was added until the solution became cloudy. The reaction mixture was allowed to cool, and as it cooled a crystalline solid formed. The solid, collected by filtration, was dissolved in methylene chloride, and the methylene chloride solution was dried with sodium sulfate. The filtrate was concentrated under reduced pressure to remove ethanol, yielding additional solid, which was collected by filtration. This solid, too, was dissolved in methylene chloride, and the solution was dried with sodium sulfate. The two methylene chloride solutions were filtered from the sodium sulfate and the filtrates combined and concentrated under reduced pressure to give a residual solid. The solid was recrystallized from ethanol-water to give 48.3 grams of 2-chlorobenzaldoxime; mp 73.5°-75.5° C. The nmr and the ir spectra were consistent with the assigned structure.

Provenance & Evidence