Cyclopropylamine → 1-Cyclopropyl-3-ethoxycarbonyl-7,8-difluoro-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

Participants

Reaction Conditions

Reaction Steps

A solution of ethyl 2-(2-chloro-6,7-difluoro-3-quinolinecarbonyl)-3-(dimethylamino)acrylate (20 g) and cyclopropylamine (9.25 g) in trichloromethane (80 cc) is stirred at a temperature in the region of 20° C. for 5 hours. The solution is concentrated under reduced pressure (20 kPa) at approximately 40° C. The residue is taken up in ethanol (300 cc), treated with DBU (8.2 g) and heated with stirring to approximately 75° C. for 30 minutes. After cooling to approximately 20° C., the insoluble matter is drained and washed with ethanol (2×30 cc). 1-Cyclopropyl-3-ethoxycarbonyl-7,8-difluoro-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine (11.1 g) is obtained in the form of a yellow solid, m.p. 230° C.

Provenance & Evidence