2-(tert-Butoxycarbonyloxyimino)-2-phenylacetonitrile → 7-Tert-butoxycarbonylamino-5-benzyl-5-azaspiro[2,4]heptane

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Reaction Steps

In 30 ml of tetrahydrofuran was dissolved 800 mg of compound 6 followed by the addition of 1.2 g of 2-(tert-butoxycarbonyloxyimino)-2-phenylacetonitrile (BOC-ON) at room temperature and the mixture was stirred at that temperature for 2 hours. The solvent was then removed under reduced pressure and to the residue was added chloroform. The mixture was extracted with a 10% aqueous citric acid. The citric acid extract was adjusted to pH≥10 with 1N aqueous sodium hydroxide and extracted with chloroform. The extract was dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure to give 900 mg of 7-tert-butoxycarbonylamino-5-benzyl-5-azaspiro[2.4]heptane (compound 10). 870 mg of this compound 10 was dissolved in 15 ml of ethanol and catalytic hydrogenation was carried out at 40° C. and 4.5 kg/cm2 in the presence of 500 mg of 10% palladium-on-carbon for 2 hours. The catalyst was then filtered off and the filtrate was concentrated under reduced pressure to give title compound 11. This product was used without purification in the substitution reaction.

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