反应详情

Bromination of 4′-benzyloxyacetophenone (step 2): Bromine (80 mmol) was added dropwise over 5 min to a stirred solution of 4′-benzyloxyacetophenone (70 mmol) in 40 ml chloroform. This mixture was stirred for an additional 5 min and quenched with saturated sodium bicarbonate in water until the pH reached 7. The organic layers were combined, dried over MgSO4, and concentrated to dryness. The crude mixture was purified over a silica gel column and eluted with methylene chloride to yield 2-bromo-4′-benyloxyacetophenone. An Rf of 0.62 was observed when resolved by thin layer chromatography using methylene chloride. 1H nmr (δ, ppm, CDCl3), 7.97 (2H, δ, 9.2 Hz, O—Ar—C(O)), 7.43 (5H, m, Ar′CH2O—), 7.04 (2H, δ, 9.0 Hz, O—Ar—C(O)), 5.15 (2H, s, Ar′CH2O—), 4.40 (2H, s, CH2Br).

1. customquenched with saturated sodium bicarbonate in water until the pH
2. dry with materialdried over MgSO4
3. concentrationconcentrated to dryness
4. customThe crude mixture was purified over a silica gel column
5. washeluted with methylene chloride