Sulfuric Acid → Tert-butyl 9-benzyl-2,2-dimethyl-1-oxa-4,9-diazaspiro[5.5]undecane-4-carboxylate

反応式

S(=O)(=O)(O)O.[CH2:6]([N:13]1[CH2:18][CH2:17][C:16]([CH2:20][NH:21][CH2:22][C:23]([CH3:25])=[CH2:24])([OH:19])[CH2:15][CH2:14]1)[C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1.[C:26](=[O:29])(O)[O-:27].[Na+]>C(#N)C>[CH2:6]([N:13]1[CH2:18][CH2:17][C:16]2([O:19][C:23]([CH3:25])([CH3:24])[CH2:22][N:21]([C:26]([O:27][C:7]([CH3:12])([CH3:8])[CH3:6])=[O:29])[CH2:20]2)[CH2:15][CH2:14]1)[C:7]1[CH:8]=[CH:9][CH:10]=[CH:11][CH:12]=1

参加物

実験手順

Concentrated sulfuric acid (12 ml) was added to 1-benzyl-4-((2-methylallylamino)methyl)piperidin-4-ol (Example 271, step a) (2.2 g) and the mixture was allowed to stand for 2 hours at room temperature. The reaction mixture was treated with ice/water (100 mL) followed by solid sodium bicarbonate, portionwise, until the mixture was basic. Acetonitrile (50 mL) was added followed by BOC-anhydride (1.925 g) and the reaction mixture stirred at room temperature for 18 hours. The reaction mixture was extracted with ethyl acetate (×2) and the combined organics were dried over sodium sulphate, filtered and the solvent evaporated under reduced pressure. The crude product was purified by flash silica chromatography, eluting with 1% methanol in dichloromethane switching to 1% methanol in dichloromethane with 1% triethylamine. Pure fractions were evaporated to dryness to afford the subtitled compound. Yield 0.8 g.