Dimethylformamide dimethyl acetal → Ethyl 1-(2,4-difluorophenyl)-7-ethylthio-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate

Participants

Reaction Steps

In 3 ml of benzene was dissolved 160 mg of ethyl 2-[2-(2,4-difluorophenylamino)-6-ethylthio-5-fluoronicotinoyl]acetate, and 72 mg of N,N-dimethylformamide dimethylacetal was added thereto, after which the resulting mixture was subjected to reaction under reflux for 2.5 hours. The solvent was removed by distillation under reduced pressure, and the residue thus obtained was purified by a column chromatography [Wako Silica Gel C-200, eluant: benzene-ethyl acetate (10:1 by volume)] to obtain 115 mg (yield 70.1%) of ethyl 1-(2,4-difluorophenyl)-7-ethylthio-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate having a melting point of 169.5°-171° C.

Provenance & Evidence