Hydrochloric Acid → Tert-butyl 2,4-dioxo-1,3,8-triazaspiro[4.5]decane-8-carboxylate

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Reaction Conditions

Reaction Steps

2.12 g (32.6 mmol) of potassium cyanide are added to a solution of 5 g (25.1 mmol) of N-tert-butoxycarbonyl-4-piperidone (34.1) and 24.01 g (250 mmol) of ammonium carbonate in 80 ml of EtOH/water=1/1 and the mixture is left to stir at 60° C. for 5 h. The pH is subsequently adjusted to 6.3 by adding 6N HCl and the mixture is stirred at 60° C. for a further 1.5 h. The precipitate is filtered off with suction and dried under high vacuum. 3.43 g of (34.2) are obtained as a colorless solid. A further 1.0 g of (34.2) is obtained by extracting the filtrate with dichloromethane, drying the organic phase over sodium sulfate, filtering and removing the solvent in vacuo. Total yield of (34.2): 4.43 g (66%) of colorless solid.

Provenance & Evidence