反应详情

To tert-butyl 2-benzyl-4,4-dimethyl-5-oxa-2,9-diazaspiro[5.5]undecane-9-carboxylate (560 mg, 1.50 mmol) was added hydrogen chloride (7.5 mL of 4 M in dioxane, 29.90 mmol), followed by ethanol (2 mL) and the reaction mixture was stirred for 30 minutes. The reaction mixture was concentrated in vacuo, dissolved in water (5 mL), washed with methyl tert-butyl ether (5 mL), basified with solid NaHCO3 then adjusted to pH 13-14 with 50% aq. NaOH. The aqueous layer was extracted with ethyl acetate (3×25 mL), dried over MgSO4 and concentrated to give 2-benzyl-4,4-dimethyl-5-oxa-2,9-diazaspiro[5.5]undecane (400 mg, 98%) as a yellow oil, which was used directly without further purification. ESI-MS m/z calc. 274.4. Found 275.5 (M+1)+; Retention time: 0.75 minutes (3 min run).

1. concentrationThe reaction mixture was concentrated in vacuo
2. dissolutiondissolved in water (5 mL)
3. washwashed with methyl tert-butyl ether (5 mL)
4. extractionThe aqueous layer was extracted with ethyl acetate (3×25 mL)
5. dry with materialdried over MgSO4
6. concentrationconcentrated