Cyclopropylamine → 8-Chloro-1-cyclopropyl-3-ethoxycarbonyl-7-fluoro-4-oxo-1,4-di hydrobenzo[b][1,8]naphthyridine

Participants

Reaction Conditions

Reaction Steps

A solution of ethyl 2-(2,7-dichloro-6-fluoro-3-quinolinecarbonyl)-3-(dimethylamino)acrylate (20.6 g) and cyclopropylamine (6 g) in trichloromethane (100 cc) is stirred at a temperature in the region of 20° C. for 24 hours. The reaction mixture is concentrated under reduced pressure (2.7 kPa) at 50° C. The residue is taken up with ethanol (180 Zcc) and DBU (10 g) and the solution obtained heated to a temperature in the region of 78° C. for 4 hours. After cooling to a temperature in the region of 20° C., the precipitate obtained is drained and washed with ethanol (2×60 cc). 8-Chloro-1-cyclopropyl-3-ethoxycarbonyl-7-fluoro-4-oxo-1,4-di hydrobenzo[b][1,8]naphthyridine (13.65 g) is obtained in the form of a pale yellow solid, m.p. 256° C., which is used without further purification for the subsequent steps.

Provenance & Evidence