Trifluoroacetic acid → 5-(S)-azidomethyl-3-(4'-carboxy-3'-fluorophenyl)oxazolidine-2-one

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Reaction Steps

TFA (30 mL) was added to a solution of 5-(S)-azidomethyl-3-[4′-(tert-butoxy)carbonyl-3′-fluorophenyl]oxazolidine-2-one (6.72 g, 20 mmol) in DCM (20 mL), and the solution was kept at r.t. for 1 h. Solvents were removed under vacuum to afford 5-(S)-azidomethyl-3-(4′-carboxy-3′-fluorophenyl)oxazolidine-2-one. THF (75 mL) was added, followed by t-butanol (9.5 mL, 100 mmol), triethylamine (3.6 mL, 26 mmol), and diphenylphosphoryl azide (5.6 mL, 26 mmol). The mixture was stirred at r.t. under nitrogen atmosphere for 2 h, and then at 70° C. overnight. Solvent was removed under vacuum, and the residue distributed between ethyl acetate (150 mL) and aq. saturated sodium bicarbonate (100 mL). Aq. phase was washed with ethyl acetate (2×50 mL). Combined organic layers were washed with aq. saturated sodium bicarbonate, water, brine, and dried (MgSO4). Solvent was removed under vacuum, and the product purified by silica gel column chromatography (eluent: DCM). Yield 4.1 g (58%). MS (m/z): [M+H]+=352.

Provenance & Evidence