Thionyl Chloride → (3-Chloro-propylamino)-(4-fluoro-phenyl)-acetic acid methyl ester

To a solution of thionyl chloride (8.79 g) in chloroform (20 mL) was added (4-fluoro-phenyl)-(3-hydroxy-propylamino)-acetic acid methyl ester (14.85 g, dissolved in 60 mL of chloroform) dropwise via syringe. The reaction mixture was then stirred for 1.5 hours at 50° C. and the volatiles were subsequently removed in vacuo to give a solid residue which was triturated with diethyl ether (30 mL) to give the desired HCl salt of (3-chloro-propylamino)-(4-fluoro-phenyl)-acetic acid methyl ester (14.88 g, MS (ES+): 260.1 (MH+)) as an off-white solid.