Hydrochloric Acid → 4-Phenyl-5-oxa-2,9-diazaspiro[5.5]undecan-3-one hydrochloride salt

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Reaction Steps

To tert-butyl 10-[(4-methoxyphenyl)methyl]-9-oxo-8-phenyl-7-oxa-3,10-diazaspiro[5.5]undecane-3-carboxylate (215 mg, 0.46 mmol) in acetonitrile (2.5 mL) was added water (2.5 mL) followed by the addition of ceric ammonium nitrate (500 mg, 0.91 mmol). The reaction mixture was stirred for 2 hours. After this time, a further aliquot of ceric ammonium nitrate (250 mg, 0.46 mmol) was added and the reaction mixture was stirred for an additional 45 minutes, it was then diluted with 1M aq. HCl, extracted with ethyl acetate (2×25 mL), dried over MgSO4 and concentrated in vacuo. The residue was dissolved in methanol (1 mL) and HCl (1 mL of 4 M in dioxane, 4.00 mmol) was added. The reaction mixture was stirred for 1 hour, then concentrated in vacuo to give 10-phenyl-11-oxa-3,8-diazaspiro[5.5]undecan-9-one hydrochloride salt (130 mg, 100%). ESI-MS m/z calc. 246.1. found 247.5 (M+1)+; Retention time: 0.46 minutes (3 min run).

Provenance & Evidence