Boron trifluoride → Anhydrodihydroartemisnin

Participants

Reaction Steps

To a solution of dihydroartemisinin (10.4 g) in diethyl ether (550 ml) at room temperature under nitrogen was added dropwise boron trifluoride dietherate (1.0 ml). The solution was stirred at room temperature overnight, washed with 5% NaHCO3 solution (3×100 ml); dried (MgSO4) and concentrated in vacuo. The residue was then purified by flash chromatography (SiO2; 10% ethyl acetate/hexanes) to give 9,10-anhydrodehydroartemisinin as a white solid (16.8 g, 97%). δH: 6.20 (1H, q, J=1.41 Hz, H-10), 5.55 (1H, s, H-12), 2.33-3.50 (1H, m), 1.03-2.18 (10H, m), 1.60 (3H, d, J=1.41 Hz, H16), 1.44 (3H, s, H-14), 1.00 (3H, d, J=5.98 Hz, H-15).

Provenance & Evidence