Patent ID: 8148530

Claim:
A process for preparing 3,7-diazabicyclo[3.3.1]nonane compounds of the formula 1 where R is hydrogen, hydroxyl, C 1 -C 4 alkyl; R 1 is C 1 -C 4 alkyl, C 6 -C 10 aryl, pyridinyl-C 1 -C 4 -alkyl; R 2 is C 1 -C 4 alkyl, C 6 -C 10 aryl; R 3 is C 1 -C 4 alkyl and X is C═O or C(OH) 2 , by (a) reacting a dicarboxylic ester of the formula (2) with a pyridinealdehyde of the formula (3) and an amine of the formula (4) R 2 —NH 2 (4) to give a piperidone of the formula (5) and (b) reacting the piperidones of the formula (5) thus obtained with formaldehyde and an amine of the formula R 1 —NH 2 , where R, R 1 , R 2 and R 3 are each as defined above, which comprises performing reaction stage (a) in a C 2 -C 4 -alcohol and reaction stage (b) in a C 3 -C 4 -alcohol, and removing the water of reaction formed by azeotropic distillation.