Methanol → HCID 131736386, compound

Participants

Reaction Steps

To a solution of (1S,2S,3S,4R,5S)-2,3,4-tribenzyloxy-5-[4-chloro-3-[(4-ethoxy-3-fluoro-phenyl)methyl]phenyl]-6,8-dioxabicyclo[3.2.1]octane-1-carboxylic acid 20b (1.20 g, 1.38 mmol) in methanol (30 mL) was added concentrated sulphuric acid (150 mg, 1.53 mmol) at room temperature. The mixture was stirred at room temperature for 12 hours and then 40° C. for 6 hours. The reaction mixture was quenched with saturated aqueous sodium bicarbonate (3 mL) at 0° C. and concentrated in vacuo to remove most of the solvent. To the residue was added water (20 mL). The resulting mixture was extracted with ethyl acetate (20 mL). The combined organic layers were washed with saturated brine (10 mL×2), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo and the residue was purified by silica gel chromatography eluted with PE/EtOAc(v/v)=1/1 to give the title compound 20c as colorless semi-solid (0.48 g, 46.2%). The compound was characterized by the following spectroscopic data: 1H NMR (400 MHz, CDCl3) δ(ppm): 7.43 (d, 1H), 7.36 (p, 2H), 7.27 (m, 10H), 7.15 (m, 3H), 6.86 (dd, 3H), 6.78 (m, 2H), 4.82 (q, 2H), 4.75 (d, 1H), 4.60 (d, 1H), 4.50 (d, 1H), 4.26 (d, 1H), 4.17 (dd, 2H), 4.00 (m, 5H), 3.85 (d, 1H), 3.71 (d, 1H), 3.68 (s, 3H), 1.40 (t, 3H).

Provenance & Evidence