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

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Reaction Steps

60% TFA in dichloroethane (10 ml) was added to 5-(S)-azidomethyl-3-[4′-tert-butoxycarbonyl-3′-fluorophenyl]oxazolidine-2-one (2.00 g, 5.95 mmol; prepared as described for Example 2) and the solution kept at r.t. for 1 h. Solvent was removed under vacuum to afford 5-(S)-azidomethyl-3-[4′-carboxy-3′-fluorophenyl]oxazolidine-2-one (1.65 g, 5.89 mmol, 99%). This intermediate was dissolved in DMF (15 ml), and pentafluorophenyl trifluoroacetate (1.21 ml, 7.06 mmol) and pyridine (1.91 ml, 23.6 mmol) were added with stirring. The mixture was stirred at r.t. for 3 h, most of the solvent removed under vacuum, and the residue triturated with water. The resulting precipitate was filtered, washed with water, ether, and dried under vacuum. White crystals. Yield g (2.53 g, 93%). MS (m/z): [M+H]+=463.

Provenance & Evidence