Water → 2,2,2-Trifluoro-1-(1-oxa-4,9-diazaspiro[5.5]undecan-4-yl)ethanone trifluoroacetate

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Reaction Conditions

Reaction Steps

A solution of trifluoroacetic anhydride (9.6 mL) in DCM (10 mL) was added dropwise, over a period of 15 minutes, to a stirred solution of triethylamine (15.2 mL) and tert-butyl 1-oxa-4,9-diazaspiro[5.5]undecane-9-carboxylate hydrochloride [WuXi PharmaTech] (9.95 g) in DCM (100 mL) at 0° C. under nitrogen. The resulting solution was stirred at 0° C. for 30 minutes. More triethylamine (2.5 mL) was added, followed by more trifluoroacetic anhydride (1.6 mL) in DCM (10 mL), and stirring at 0° C. was continued for 1 hour. Water (100 mL) was added and the mixture was vigorously stirred for 10 minutes. The organic layer was separated, dried, and the solvent evaporated under reduced pressure. The residue was dissolved in DCM (100 mL) and the solution treated with trifluoroacetic acid (25 mL). This mixture was allowed to stand at 20° C. for 10 minutes and then diluted with toluene (40 mL). The solvents were removed under reduced pressure and the residue azeotroped with more toluene (×2) to yield the subtitled compound. Yield 14.0 g.

Provenance & Evidence