Triphenylphosphine dibromide → 4-(Bromomethyl)-2-chloropyridine

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Reaction Steps

A solution of 0.2 g of 2-chloro-4-(hydroxymethyl)pyridine in 2.5 ml of dichloromethane is added dropwise to a solution of 0.706 g of dibromotriphenylphosphorane in 9.5 ml of dichloromethane, under an inert atmosphere of argon at a temperature in the region of 20° C. Stirring is continued at this temperature for about 1 hour. The reaction medium is taken up in 50 ml of dichloromethane and then washed with 3×50 ml of water. The organic phase is dried over magnesium sulfate, filtered and then concentrated to dryness under reduced pressure. The residue thus obtained is purified by flash chromatography using a cartridge 20 mm in diameter packed with 10 g of 20-40 μm conditioned silica, and then eluted with a mixture (cyclohexane/ethyl acetate) (8/2) (v/v) at a flow rate of 8 ml/minute. The fractions between 8 and 24 ml are concentrated under reduced pressure. 0.1 g of 2-chloro-4-(bromomethyl)-pyridine is thus obtained.

Provenance & Evidence