Citric Acid → HCID 69138135, compound

Participants

Reaction Steps

A 360 mg (1.00 mmol) portion of (R)-1-benzyloxycarbonyl-3-(1-tert-butoxycarbonylaminomethylcyclopropyl)pyrrolidine was dissolved in 10 ml of methanol to which was subsequently added 125 mg of 5% (v/v) palladium-carbon to carry out 3.5 hours of stirring at room temperature in a stream of hydrogen. After filtration through celite, methanol was evaporated. The resulting residue was mixed with 1 ml of triethylamine and 159 mg (0.50 mmol) of 6,7,8-trifluoro-[(1R,2S)-2-fluorocyclopropyl]-1,4-dihydro-5-hydroxy-4-oxoquinoline-3-carboxylic acid which has been dissolved in 10 ml of acetonitrile, and the thus prepared mixture was heated under reflux for 1 hour. After completion of the reaction, the reaction solution was mixed with 10% citric acid and extracted with chloroform (50 ml×3). The organic layer was dried over anhydrous sodium sulfate, and the solvent was evaporated. A 5 ml portion of concentrated hydrochloric acid was added dropwise to the resulting residue, followed by 1.5 hours of stirring at room temperature. After completion of the reaction, the reaction solution was adjusted to pH 12 with sodium hydroxide aqueous solution and then to pH 7.4 with hydrochloric acid, and the thus precipitated crystals were collected by filtration. The resulting filtrate was extracted with chloroform (100 ml×3). The organic layer was dried over anhydrous sodium sulfate and the solvent was evaporated. Thereafter, the resulting residue and the collected crystals were combined, and recrystallized from ethanol-liquid ammonia to yield 227 mg (82%) of the title compound.

Provenance & Evidence