反应详情

温度

0 °C

A cold (0° C.) solution of 4-hydroxymethyl-3,5-dichloropyridine (3.0 g) and N-bromosuccinimide (6.1 g) in dry dimethylformamide (100 mL) is treated with triphenylphosphine (8.9 g), portionwise, during 5 minutes. The resulting red solution is stirred at 0° C. for 45 minutes, and then treated with methanol (5 mL), followed by water (300 mL). The mixture is extracted with diethyl ether (4×200 mL), the combined organic washings dried over sodium sulfate, and the solvent removed under reduced pressure. The resulting residue is chromatographed on silica gel, eluting with a mixture of diethyl ether and pentane (1:2 v/v), to give 4-bromomethyl-3,5-dichloropyridine (3 g), in the form of an off-white solid, m.p. 40°-44° C.

1. extractionThe mixture is extracted with diethyl ether (4×200 mL)
2. dry with materialthe combined organic washings dried over sodium sulfate
3. customthe solvent removed under reduced pressure
4. customThe resulting residue is chromatographed on silica gel
5. washeluting with a mixture of diethyl ether and pentane (1:2 v/v)