Ammonium Chloride → tert-Butyl 6-oxo-2-azaspiro(3.3)heptane-2-carboxylate

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Reaction Steps

15.13 g (0.283 mmol) of ammonium chloride are added to a solution containing 13.21 g (47.15 mmol) of tert-butyl 5,5-dichloro-6-oxo-2-azaspiro[3.3]heptane-2-carboxylate, obtained in the preceding step, in 250 mL of methanol. The reaction medium is cooled with the aid of an ice/water bath, and 30.83 g (0.471 mmol) of zinc are added. After stirring at room temperature for 12 hours, the Celite is filtered off and rinsed with methanol. The filtrate is evaporated to dryness. The residue obtained is taken up in water and extracted several times with ethyl acetate. The combined organic phases are dried over sodium sulfate and the filtrate is concentrated under reduced pressure. After evaporating off the solvent, the residue obtained is purified by chromatography on silica gel, eluting with a 90/10 mixture of cyclohexane and ethyl acetate. 1.78 g of pure product are thus obtained in the form of a white powder.

Provenance & Evidence