反应详情

A suspension of 1.2 g of 1-cyclopropyl-3-ethoxycarbonyl-7,8-difluoro-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine in 1.4 g of 1-methylpiperazine and 20 cm3 of dimethyl sulphoxide is heated at a temperature close to 95° C. for 45 minutes. After cooling to a temperature close to 20° C., the reaction mixture is diluted with 100 cm3 of water and extracted with 3 times 30 cm3 of trichloromethane. The combined organic extracts are washed with 3 times 30 cm3 of water, dried over magnesium sulphate, filtered and concentrated under reduced pressure (20 kPa) at a temperature close to 50° C. The solid obtained is taken up in 20 cm3 of diisopropyl ether, drained, washed with 10 cm3 of the same solvent and recrystallized from 150 cm3 of ethyl acetate. 1.1 g of 1-cyclopropyl-3-ethoxycarbonyl-7-fluoro-8 -(4-methyl-1-piperazinyl)-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine are obtained in the form of a yellow solid melting at 223° C.

1. temperatureis heated at a temperature
2. customclose to 95° C. for 45 minutes
3. temperatureAfter cooling to a temperature
4. customclose to 20° C.
5. extractionextracted with 3 times 30 cm3 of trichloromethane
6. washThe combined organic extracts are washed with 3 times 30 cm3 of water
7. dry with materialdried over magnesium sulphate
8. filtrationfiltered
9. concentrationconcentrated under reduced pressure (20 kPa) at a temperature
10. customclose to 50° C
11. customThe solid obtained
12. washwashed with 10 cm3 of the same solvent
13. customrecrystallized from 150 cm3 of ethyl acetate