Acetic Acid → 3-O-Methylmycarose

Participants

Reaction Steps

A sample of the compound from Step 2b (330 mg) was stirred in a solution of water (0.5 mL) and acetic acid (0.25 mL) in acetonitrile (2 mL) for 2 hours. The mixture was diluted with ethyl acetate and washed with saturated aqueous sodium bicarbonate solution. The organic phase was washed with water and brine, dried over MgSO4, and concentrated in vacuo. The residue was re-treated with the same procedure (4 hours) to hydrolyse remaining protecting groups. The product was re-isolated as described, then purified by chromatography on silica gel, eluting with 1:98:1 methanol/dichlomethane/ammonium hydroxide to give the title compound (78 mg). 13C NMR (CDCl3) δ 82.6(C-9), 175.4(C-1), 153.4(carbonate carbonyl carbon), 102.9, 96.2, 88.6, 85.8, 84.0, 82.8, 80.3, 79.7, 77.9, 76.8, 72.6, 70.9, 68.9, 65.6, 65.4, 49.4, 44.9, 40.2, 39.6, 39.2, 34.9, 34.4, 28.6, 28.5, 21.8, 21.5,21.4, 19.8, 18.6, 17.8, 16.5, 15.9, 15.5, 9.9, 9.2. MS FAB High Resolution (M+H)+ : calcd: 787.4592; observed: 787.4606.

Provenance & Evidence