Hydrochloric Acid → Ethyl 1-cyclopropyl-6,7-difluoro-1,2,3,4-tetrahydro-8-methoxy-2-methyl-5-nitro-4-oxoquinoline-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of ethyl 1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-5-nitro-4-oxoquinoline-3-carboxylate (2.50 g, 6.79 mmol) and cuprous iodide (389 mg, 2.04 mmol) in THF (70 mL), 3 M methylmagnesium chloride in THF (3.40 mL, 10.2 mmol) was added under argon atmosphere at −78° C. After stirred at −78° C. for 1 h and at room temperature for 1 h, the reaction mixture was poured into ice-water (300 mL) and concentrated HCl (30 mL) was added to stirred for 30 min. The crude product was extracted with EtOAc, washed with brine, dried over MgSO4 and the solvent was removed in vacuo. The crude product was purified by column chromatography (Hexane:EtOAc 20:1→5:1) to yield ethyl 1-cyclopropyl-6,7-difluoro-1,2,3,4-tetrahydro-8-methoxy-2-methyl-5-nitro-4-oxoquinoline-3-carboxylate (1.44 g, 55%) as a yellow solid.

Provenance & Evidence