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

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Reaction Steps

60% TFA in DCM (5 mL) was added to 5-(S)-azidomethyl-3-[4′-tert-butoxycarbonyl-3′-fluorophenyl]oxazolidine-2-one (0.336 g, 1 mmol), and the solution kept at r.t. for 1 h. Solvents were removed in vacuo to afford 5-(S)-azidomethyl-3-[4′-carboxy-3′-fluorophenyl]oxazolidine-2-one (0.280 g, 99%). A mixture of 5-(S)-azidomethyl-3-[4′-carboxy-3′-fluorophenyl]oxazolidine-2-one well stirred mixture of (0.080 g, 0.286 mmol) and thiosemicarbazide (0.0957 g, 0.286 mmol) in dioxane (2 mL) was heated until the mixture was homogeneous. Phosphorous oxychloride (0.027 ml, 0.29 mmol) was added, and the mixture heated at reflux for 1 h. The mixture was allowed to cool to r.t., and the white precipitate filtered, washed with dioxane, suspended in saturated aqueous sodium bicarbonate, and extracted with ethyl acetate. Combined oganic extracts were washed with brine, and dried (MgSO4) Solvent was removed under vacuum, and the crude product purified by PTLC (10% MeOH in DCM) to give product as a white solid (0.038 g, 40%); MS (m/z): [M+H]+=336.

Provenance & Evidence