Sulfuric Acid → HCID 44546741, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of Compound 16 (˜110 mmol) in methylene chloride (1.0 L) was added concentrated sulfuric acid (30.0 mL, 0.56 mol) and the mixture was stirred at 0° C. for 3 h. The reaction was quenched by adding 6 N NaOH until the pH was ˜9, and the aqueous phase was extracted with additional methylene chloride (3×). The combined organic extracts were dried over sodium sulfate, filtered and concentrated. The residue was purified by flash chromatography (9:1 to 8:1 hexanes/ethyl acetate) to afford Compound 17 (15.79 g, 41% over 3 steps) as a white solid: 1H NMR (500 MHz, CDCl3) δ 7.82-7.70 (m, 3H), 7.66 (s, 1H), 7.49-7.41 (m, 2H), 7.28-7.20 (m, 2H), 7.16 (dd, J=8.3, 2.3 Hz, 1H), 6.75 (d, J=8.5 Hz, 1H), 4.37 (dd, J=7.5, 6.5 Hz, 1H), 3.75 (d, J=15.3 Hz, 1H), 3.62 (d, J=15.3 Hz, 1H), 3.08 (ddd, J=11.5, 6.0, 1.0 Hz, 1H), 2.64 (dd, J=11.5, 8.5 Hz, 1H), 2.43 (s, 3H). The undesired 5-bromo isomer was also obtained (11.91 g, 30% over 3 steps).

Provenance & Evidence