Water → 3-Benzyl-2-oxo-1-oxa-3,8-diazaspiro[4.5]decane-8-carboxylic acid tert-butyl ester

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Reaction Steps

Sodium hydride (82 mg, 60% dispersion in mineral oil, weight percent) was suspended under a nitrogen atmosphere in DMF (5 mL). Compound A3 (0.5 g, 1.95 mmol) was added thereto and the reaction mixture was stirred for 10 min at RT. Benzyl bromide (235 μL, 1.97 mmol) was added thereto. The reaction mixture was stirred for 18 h at RT, combined with water and extracted with EtOAc. The combined organic phases were washed with sat. aq. NaCl solution, dried over Na2SO4 and the solvent was removed under a vacuum. The residue was dissolved in a mixture of ether and heptane. After removal of the ether, the desired product 3-benzyl-2-oxo-1-oxa-3,8-diazaspiro[4.5]decane-8-carboxylic acid tert-butyl ester (A4) (0.54 g, 80% of theoretical) was obtained as a white solid by filtration.

Provenance & Evidence