Dimethylformamide → 5-Benzyl-7-t-butoxycarbonylamino-4-oxo-7-methyl-5-azaspiro[2.4]heptane

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Reaction Steps

A dimethylformamide solution (65 mL) of 7-(tert-butoxycarbonylamino)-7-methyl-5-azaspiro[2.4]heptan-4-one (3.12 g, 12.97 mmol) was added sodium hydride (55%, mineral oil dispersion, 538 mg, 12.33 mmol) over 5 minutes under cooling with ice. This solution was stirred at the same temperature for 40 minutes. After that, to the solution was added benzyl bromide (1.851 mL, 15.56 mmol), and the mixture was stirred at room temperature for 1.5 hours. To this reaction mixture was added ethyl acetate (300 mL) to dilute the mixture, and the mixture was washed with water (100 mL, ×2) and saturated brine (100 mL). To the solution was added anhydrous sodium sulfate to dry the solution. The drying agent was removed by filtration, and then the solvent was removed under reduced pressure. Thus-obtained residue was purified with silica gel column chromatography (hexane/ethyl acetate in the ratio of and in the order of 9:1, 4:1, and 2:1) to obtain 4.20 g (12.71 mmol, 98%) of the target compound as a transparent and colorless gum-like solid.

Provenance & Evidence