反应详情

Methylene chloride solution (0.667 ml) of 1M titanium tetrachloride was gradually added to a solution of methylene chloride (2 ml) and tetrahydrofuran (54.3 μ) containing ethyl 6,7,8-trifluoro-1-methylamino-1,4-dihydro-4-oxoquinoline-3-carboxylate (200 mg), with stirring under ice-cooling, and then tert-butyl 2-tert-butoxycarbonylacrylate (0.228 g) was added thereto and stirred for 10 minutes with ice-cooling and then for 15 hours at room temperature. The mixture was poured into a mixture of ethyl acetate (20 ml) and water (20 ml). The organic layer separated was washed with brine and dried over magnesium sulfate, and the solvent was removed by distillation under reduced pressure. The residue was then triturated with n-hexane. The precipitates were taken out by filtration and dried with air to obtain ethyl 6,7,8-trifluoro-1-[N-methyl-N-{2,2-bis(tert-butoxycarbonyl)ethyl}amino]-1,4-dihydro-4-oxoquinoline-3-carboxylate (775.8 mg) as a pale yellow powder.

1. temperaturecooling
2. stirringstirred for 10 minutes with ice-
3. temperaturecooling
4. customThe organic layer separated
5. washwas washed with brine
6. dry with materialdried over magnesium sulfate
7. customthe solvent was removed by distillation under reduced pressure
8. customThe residue was then triturated with n-hexane
9. filtrationThe precipitates were taken out by filtration
10. customdried with air