Hydrochloric Acid → Khellinone

Participants

Reaction Steps

To a stirred solution of potassium hydroxide (193.2 g) in 1.5 l of water, heated to 75° C., is added 300 g of khellin (formula XXI) in 50 g portions over a period of 30 minutes. When khellin addition is complete, the resulting mixture is then heated to reflux for 2 hr and thereafter cooled to ambient temperature. Concentrated hydrochloric acid (300 ml) is then added to the cooled solution and the resulting precipitate is collected by filtration and dried at ambient temperature in a vacumn for 18 hr. The resulting crude yellow solid is then recrystallized from one liter of methanol, yielding 251 g of pure title product. Melting point is 99°-100° C. Silica gel TLC Rf is 0.60 is hexane and ethyl acetate (1:1). Infrared absorptions are observed at 3160, 3140, 1700, 1695, 1680, 1620, 1590, 1550, 1300, 1265, 1150, 1075, and 1060 cm-1. NMR absorptions are observed at 7.52, 6.91, 4.15, 4.05, 2.27, and 13.06δ (deuterochloroform solvent). The mass spectrum exhibits peaks at 236, 221, 206, 203, 191, 175, 163, and 119. Carbon:hydrogen ratio is 60.65:5.15.

Provenance & Evidence