Reaction Steps
A solution of codeine (30 g, 100.2 mmol), acetic anhydride (18.4 g, 180.2 mmol), triethylamine (18.25 g, 180.2 mmol) and 4-dimethylaminopyridine (0.5 g) in dry ethyl acetate (620 ml) was stirred at rt. under nitrogen for 12 hr, added saturated aqueous sodium bicarbonate solution until no acetic anhydride detected. The organic portion was separated, washed with water (3×120 ml), dried over anhydrous sodium sulfate, and evaporated in vacuo to dryness to give 6-acetylcodeine as white solids (34.0 g, 99% yield). IR (KBr)(ν, cm-1): 1725 (st, sharp, 3-AcO); NMR (δH)(CDCl3): 6.66 (1, d, J, 8.2, 2-H), 6.53 (1, d, J, 8.2, 1-H), 5.63 (1, ddd, J, 10.0, 2.4 & 1.0, 7-H), 5.42 (1, dt, J, 9.9 & 2.3, 8-H), 5.22-5.51 (1, m, 6-H), 5.06 (dd, J, 6.7 & 1.0, 5-H, 3.85 (3, s, 3-OCH3), 3.39 (1, dd, J, 6.0 & 3.3, 9-H), 3.03 (1, d, Jjam, 18.6, 10-Hβ), 2.78 (1, dd, J, 5.2 & 2.6, 14-H), 2.63 (1, dd, J, 11.9 & 4.6, 16-Ha), 2.45 (3, s, N--CH3), 2.40 (1, td, J, 12.0 & 3.8, 16-He), 2.33 (1, dd, J, 18.5 & 6.0, 10-Hα), 2.15 (3, s, 6-OAc), 2.06 (1, td, J, 12.0 & 5.0, 15-Ha) and 1.85 (1, dm, J, 12.0, 15-He).
