Thionyl Chloride → Ethyl 4-chloro-6-fluoroquinoline-3-carboxylate

Participants

Reaction Steps

A mixture of 6-fluoro-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid ethyl ester (4.4 g, 18.7 mmol) in thionyl chloride (50 mL) was heated at reflux for 3 hours (at 30 min. mixture changed to a clear solution). The resultant solution was cooled to room temperature, and the excess thionyl chloride was evaporated in vacuo. The residue was added to ammonium hydroxide on ice (note: highly exothermic). Let resultant mixture stir for 15 minutes, and the product was collected by filtration and washed generously with water. The solid was purified by flash chromatography, on silica gel, eluted with a gradient of ethyl acetate (0% to 30%) in heptane, to give the product, 4.24 g (89%) as a colorless solid. MS: m/z 253.8 (MH+).

Provenance & Evidence