[H-].[Al+3].[Li+].[H-].[H-].[H-].[CH2:7]([N:14]1[CH2:23][CH2:22][CH2:21][C:15]21[C:19](=O)[NH:18][CH2:17][CH2:16]2)[C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1.[OH-].[Na+].[H][H]>C1COCC1>[CH2:7]([N:14]1[C:15]2([CH2:16][CH2:17][NH:18][CH2:19]2)[CH2:21][CH2:22][CH2:23]1)[C:8]1[CH:9]=[CH:10][CH:11]=[CH:12][CH:13]=1Lithium aluminum hydride (1.98 g, 52.2 mmol) was added in portions, under argon, to a ice bath cooled solution of 6-benzyl-2,6-diazaspiro[4.4]nonan-1-one (4.00 g, 17.4 mmol) in dry THF (100 mL). The addition funnel was replaced with a reflux condenser, and the mixture was heated at reflux for 24 h. The mixture was cooled to 0° C. and treated drop-wise (caution: exothermic reaction) with 10 M aqueous sodium hydroxide until hydrogen evolution ceased and the aluminate salts were granular. The mixture was stirred 1 h at 0° C. and filtered through Celite. The filtrate was dried (K2CO3) and concentrated, leaving 3.60 g (95.7%) of viscous, colorless liquid.
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