反应详情

In 30 ml of methylene chloride was suspended 3.00 g of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-7-hydroxy-4-oxo-1,8-naphthyridine-3-carboxylate, and 1.02 g of triethylamine and 2.20 g of ortho-nitrobenzenesulfonyl chloride were added thereto with ice-cooling, after which the resulting mixture was subjected to reaction at the same temperature for 30 minutes and then at room temperature for 6 hours. The reaction mixture was washed with three 50-ml portions of water and then dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure, and to the residue thus obtained was added a mixture of 6 ml of ethyl acetate and 12 ml of diethyl ether, after which the crystals thus deposited were collected by filtration to obtain 4.40 g (yield 97.2%) of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-7-(2-nitrobenzenesulfonyloxy)-4-oxo-1,8-naphthyridine-3-carboxylate having a melting point of 157°-160° C.

1. additionwere added
2. temperaturewith ice-cooling
3. customafter which the resulting mixture was subjected to reaction at the same temperature for 30 minutes
4. washThe reaction mixture was washed with three 50-ml portions of water
5. dry with materialdried over anhydrous magnesium sulfate
6. customThe solvent was removed by distillation under reduced pressure
7. customto the residue thus obtained
8. additionwas added
9. filtrationafter which the crystals thus deposited were collected by filtration