Methanol → 4-(Bromomethyl)-3,5-dichloropyridine
Reaction equation
O[CH2:2][C:3]1[C:8]([Cl:9])=[CH:7][N:6]=[CH:5][C:4]=1[Cl:10].[Br:11]N1C(=O)CCC1=O.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.CO>CN(C)C=O.O>[Br:11][CH2:2][C:3]1[C:8]([Cl:9])=[CH:7][N:6]=[CH:5][C:4]=1[Cl:10]Participants
7
Conditions
- Temperature
- 0 °C
Procedure
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.
Workup
- extractionThe mixture is extracted with diethyl ether (4×200 mL)
- dry with materialthe combined organic washings dried over sodium sulfate
- customthe solvent removed under reduced pressure
- customThe resulting residue is chromatographed on silica gel
- washeluting with a mixture of diethyl ether and pentane (1:2 v/v)
Sources & evidence
- ORD record
- ord-32da9f33367940dda99b4480a5b4cecf
- Source dataset
- uspto-grants-1998_11
- Patent number
- US05840724
Reaction notes
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