1,1-Bis(2,2-dimethylpropoxy)-N,N-dimethylmethanamine → Ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-7-hydroxy-4-oxo-1,8-naphthyridine-3-carboxylate

Participants

Reaction Steps

In 4 ml of toluene was suspended 200 mg of ethyl 2-[2-(2,4-difluorophenylamino)-5-fluoro-6-hydroxynicotinoyl]acetate, and 200 mg of N,N-dimethylformamide dineopentylacetal was added thereto, after which the resulting mixture was subjected to reaction at room temperature for 4 hours. The crystals thus deposited were collected by filtration, and to the crystals were added 5 ml of ethanol and 5 ml of water, after which the pH thereof was adjusted to 1.0 with 2N hydrochloric acid. Thereafter, the crystals thus deposited were collected by filtration to obtain 155 mg (yield 75.4%) of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-7-hydroxy-4-oxo-1,8-naphthyridine-3-carboxylate having a melting point of 244°-248° C. The physical properties of this compound were identical with those of the compound obtained in Example 40.

Provenance & Evidence