HCID 53988412, compound → HCID 13987622, compound

Participants

Reaction Steps

A solution of ethyl 4-[3-[(2,4-dioxoimidazolin-5-ylidene)methyl]-4-nitrophenyl]-1-piperazinecarboxylate (4.25 g, 10.9 mmol) in DMF (200 mL) was hydrogenated over 10% Pd/C (0.7 g) at 60 p.s.i. After 17 hours, the mixture was filtered through kieselguhr and the solvent removed in vacuo. Evaporation was repeated with two portions (200 mL each) of methanol. Residual solid was suspended in absolute ethanol (200 mL) and glacial acetic acid (8 mL) and stirred at reflux for one hour. The mixture was concentrated in vacuo, the residue suspended in DMF (200 mL) and warmed to solution on a steam bath. Palladium on carbon (0.5 g) was added and heating continued for two hours. The mixture was filtered through kieselguhr, the filtrate concentrated to a slurry and diluted with methanol. The precipitate was collected and crystallized from DMF to afford ethyl 4-(2,3-dihydro-2-oxo-1H-imidazo[4,5-b]quinolin-7-yl)-1-piperazinecarboxylate, a yellow solid (0.74 g) of analytical purity, m.p. >300° C.

Provenance & Evidence