Trifluoroacetic anhydride → Anhydrodihydroartemisnin

To a solution of dihydroartemisinin (500 mg, 1.86 mmol) in dichloromethane (28 ml) at 0° C. under nitrogen was added 4-(N,N-dimethylamino)pyridine (37 mg) and trifluoroacetic anhydride (0.79 ml, 5.58 mmol). The mixture was allowed to warm to room temperature and stirred overnight. The solution was then concentrated in vacuo. The residue was purified by flash chromatography (SiO2; ether:hexane from 0.5:9.5 to 1.5:8.5) to give 9,10-anhydro-10-deoxoartemisinin (9,10-anhydroartemisinin) (180 mg, 25%) as a white solid. M.p. 100° C.; [α]D20.5 +155.74° (c. 0.0101 in CHCl3); νmax (film): 2948, 2922, 2862, 2850, 1684, 1432, 1372, 1334, 1198, 1178, 1158, 1142, 1114, 1078; 1028, 1016, 992, 954, 944, 904, 880, 828, 812; δH: 6.18 (1H, s, H-10), 5.54 (1H, s, H-12), 2.40 (1H, ddd, J=17.1, 13.2, 4.14 Hz, H-9), 2.00-2.09 (2H, m), 1.88-1.95 (1H, m), 1.07-1.73 (8H, m), 1.58 (3H, d, J=1.37 Hz, H-16) 1.42 (3H, s, H-14), 0.98 (3H, d, J=5.98 Hz, H-15); m/z (EI): 380 (M+); Anal. Calc. for C15H22O4: C, 67.67; H, 8.27. Found: C, 67.63; H, 8.51.

1. concentrationThe solution was then concentrated in vacuo
2. customThe residue was purified by flash chromatography (SiO2; ether:hexane from 0.5:9.5 to 1.5:8.5)

ORD record

ord-d5367eda03b64ed4be1b948da1d08e0d

Source dataset

uspto-grants-2008_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07439238B2