HCID 178471852, compound → 1-Cyclopropyl-3-ethoxycarbonyl-7,8-difluoro-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

Participants

Reaction Conditions

Reaction Steps

A stirred suspension of 5.27 g of ethyl 2-(2-chloro-6,7-difluoro quinoline-3-carbonyl)-3-cyclopropylaminoacrylate in 2.22 g of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 120 cm3 of ethanol is heated at a temperature close to 75° C. for 35 minutes. After cooling to about 20° C., the reaction mixture is taken up in 100 cm3 of water and extracted with once 100 cm3 and twice 50 cm3 of trichloromethane. The combined organic extracts are washed with 3 times 50 cm3 of water, dried over magnesium sulphate, filtered and concentrated under reduced pressure (20 kPa) at a temperature close to 20° C. The dry extract obtained is taken up in 30 cm3 of diisopropyl ether, drained and recrystallized from a mixture of 75 cm3 of ethanol and 75 cm3 of dimethylformamide. 3.57 g of 1 -cyclopropyl-3-ethoxycarbonyl-7,8-di fluoro-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine are obtained in the form of a yellow solid melting at 229°-230° C.

Provenance & Evidence