Sodium hydride → Fluoroquinolonic acid

Participants

Reaction Steps

3.44 g of 80 percent strength sodium hydride are added in portions to a stirred ice-cooled solution of 31.9 g of ethyl 2-(2,4-dichloro-5-fluoro-benzoyl)-3-cyclopropylamino-acrylate (6) in 100 ml of anhydrous dioxane. Thereafter, the mixture is stirred for 30 minutes at room temperature and for 2 hours under reflux, and the dioxane is stripped off in vacuo. The residue (40.3 g) is suspended in 150 ml of water, 6.65 g of caustic alkali are added and the mixture is refluxed for 1.5 hours. The warm solution is filtered, and the residue is rinsed with H2O. The ice-cooled filtrate is then acidified to pH=1-2 with semi-concentrated hydrochloric acid, and the precipitate is filtered off under suction, washed with water and dried in vacuo at 100° C. In this manner, 27.7 g of 7-chloro-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-quinoline-3-carboxylic acid Via of melting point 234°-237° C. are obtained.

Provenance & Evidence