Hydrochloric Acid → 6′-Methoxy-9-rubanone

Participants

Reaction Steps

A solution of benzophenone (1.12 kg) in toluene (4 L) was treated with quinine (1.00 kg) and potassium t-butoxide (871 g). The resulting mixture was heated to reflux for six hours, then allowed to cool to room temperature. After about 18 hours, this mixture was cooled to a temperature of about 10° C. to about 15° C. This cold mixture was treated with 2 N hydrochloric acid (4 L) at a rate such that the temperature of the mixture was less than 30° C. The resulting mixture was treated with additional 2 N hydrochloric acid (3 L) and the phases separated. The organic phase was extracted with additional 2 N hydrochloric acid (2×2.5 L). The combined aqueous phase was cooled to a temperature of about 5° C. to about 15° C., and the pH adjusted to pH 9-9.5 with the addition of 5 N sodium hydroxide (ca. 2.6 L). The resulting mixture was stirred at about 5° C. to about 20° C. for one hour. The crystalline material was removed by filtration, rinsed with water (2×1 L), and dried in vacuo at 50° C. to give 1.02 kg of quininone.

Provenance & Evidence