Pyridine → Diethyl [chloro(4-chlorophenyl)methyl]phosphonate

Participants

Reaction Steps

9.2 g (0.0768 mole) of thionyl chloride were added to a mixture of 20.2 g (0.0725 mole) of 4-chloro-α-hydroxy-benzylphosphonic acid diethyl ester, 65 g of methylene chloride and 5.8 g (0.0725 mole) of pyridine at 20° to 40° C. in the course of about 1 hour, while cooling slightly with water. The reaction mixture was then heated under reflux for 3 hours and was subsequently stirred for 12 hours without further heating. The mixture was poured onto about 100 g of ice-water and the organic phase was separated off and dried. After distilling off the solvent, the residue was concentrated under 6 mm Hg and at 45° C. 21 g (97.7% of theory) of 4-chloro-α-chloro-benzyl-phosphonic acid diethyl ester were obtained as a yellow viscous oil with a purity of 98.6% (gas chromatogram) and a refractive index nD24 of 1.5250.

Provenance & Evidence