反应详情

温度

87 °C

A suspension of 2,2′-(1,3-phenylene)diethanol (step c) (1.03 kg, 6.22 mol, 1.0 equiv.) in toluene (13.49 L, 15.0 vols) and 48% HBr (1.44 L, 12.75 mol, 2.05 equiv.) was heated at 87° C. for 14 h. Additional 48% w/w HBr (0.35 L 3.11 mol, 0.5 equiv.) was charged and the mixture was stirred at reflux for a further 24 h. The mixture was cooled to ambient and the layers were separated. The organic layer was concentrated to afford 1.39 kg of material. The purification was split into two equal batches of 800 g. The crude meta-bromoalcohol (800 g) was dissolved in DCM (1.6 L, 2 vols w.r.t. the mass of crude material) and charged to a dry pad of silica gel (3.6 kg, 4 wt equiv.). The pad was eluted with 10% IPAc/Heptane (16 L) to remove the fast running impurities then 50% IPAc/Heptane (20 L) to wash off the product. The product containing fractions from each of the silica pads were combined, concentrated at 40-45° C. and then dried to constant weight to afford 1.32 kg (81% Th.) of meta-bromoalcohol as a pale yellow oil.

1. temperatureat reflux for a further 24 h
2. temperatureThe mixture was cooled to ambient and the layers
3. customwere separated
4. concentrationThe organic layer was concentrated