Acetic Acid → (-)-Norcocaine

Participants

Reaction Steps

Cocaine (500 mg) was dissolved in a mixture (21 ml) of acetonitrile and water (1:2). Acetic acid (0.5 ml) was added to the solution to adjust its pH to approximately 5. To the solution was added dropwise 21 ml aqueous potassium permanganate (KMnO4=534 mg, 3.78 mmol, 2.05 eq.) over 3 hours. The solution was stirred overnight at room temperature. After removing the resulting precipitate by filtration, potassium carbonate (1050 mg) was added to the filtrate to adjust its pH to approximately 8. The filtrate was extracted with ether three times and dried over anhydrous sodium sulfate overnight. The sodium sulfate was removed out of the extract and ether was distilled off under reduced pressure to give colorless liquid. The liquid was purified by silica-gel thin layer chromatography (hereinafter abbreviated as TLC) using as an eluent ammonia saturated chloroform to give norcocaine (269 mg) of Formula (4):

Provenance & Evidence