Trifluoroacetic acid → 8-Ethyl-10-phenyl-11-oxa-3,8-diazaspiro[5.5]undecane

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Reaction Steps

To tert-butyl 8-ethyl-10-phenyl-11-oxa-3,8-diazaspiro[5.5]undecane-3-carboxylate (540 mg, 1.50 mmol) in DCM (1.5 mL) was added 2,2,2-trifluoroacetic acid (1 mL, 12.98 mmol) and the solution was stirred for 30 minutes. The reaction mixture was concentrated in vacuo, diluted with DCM (50 mL), washed with 1:1 sat. aq. Na2CO3/NaHCO3 (10 ml) and the aqueous was extracted further with DCM (2×25 mL). The combined organics were dried (MgSO4) and evaporated to give 8-ethyl-10-phenyl-11-oxa-3,8-diazaspiro[5.5]undecane (390 mg, 100%) as a pale yellow solid, which was used without further purification. ESI-MS m/z calc. 260.4. found 261.3 (M+1)+; Retention time: 0.3 minutes (3 min run).

Provenance & Evidence