Toluene → Ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-7-methoxy-4-oxo-1,8-naphthyridine-3-carboxylate

Participants

Reaction Steps

To 4 ml of toluene was added 540 mg of (N,N-dimethylformamide-dimethyl sulfate) complex compound, and 85 mg of sodium methoxide was added thereto at 0° C., after which the resulting mixture was subjected to reaction at 0° to 10° C. for 1 hour. Subsequently, 200 mg of ethyl 2-[2-(2,4-difluorophenylamino)-5-fluoro-6-methoxynicotinoyl]acetate was further added to the reaction mixture, and the resulting mixture was subjected to reaction under reflux for 1.5 hours. The reaction mixture was added to a mixture of 8 ml of ethyl acetate and 8 ml of water, and the organic layer was separated, washed with 5 ml of saturated aqueous sodium chloride solution, and then dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure, and to the crystalline material thus obtained was added 1 ml of diethyl ether, after which crystals were collected by filtration to obtain 170 mg (yield 82.8%) of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-7-methoxy-4-oxo-1,8-naphthyridine-3-carboxylate. The physical properties of this compound were identical with those of the compound obtained in Example 41.

Provenance & Evidence