542-05-2

111-30-8

100-46-9

2291-58-9

1. Benzylamine (5.0 g, 47 mmol) and Na?HPO?-12H?O (5.0 g) were dissolved in 50 mL of water and cooled in an ice water bath. 2. a 25% aqueous solution of 1,3-acetone dicarboxylic acid (8 g, 20 mmol, 1.0 eq.) was slowly added with stirring. 3. After the dropwise addition was completed within 60 minutes, the reaction mixture was allowed to warm slowly to room temperature and stirring was continued for 24 hours. 4. Upon completion of the reaction, the pH was adjusted to 3 with concentrated hydrochloric acid. 5. The reaction mixture was transferred to an oil bath at 50 °C, stirred for 2 hours and then cooled to room temperature. 6. The pH was adjusted to 10 with 20% NaOH solution, then extracted twice with dichloromethane and the organic phases were combined. 7. The organic phase was washed once with saturated brine and concentrated under reduced pressure to give a yellow solid crude product of 9-benzyl-9-azabicyclo[3.3.1]nonan-3-one. 8. The crude product was purified by crystallization with a solvent mixture of ethyl acetate and petroleum ether in the ratio of 1:5 by volume, and 9 g of light yellow solid product was obtained after filtration in 91% yield.