| abstract |
This invention relates to a process for the preparation of pyrido[2,1-a]isoquinoline derivatives of the formula n n nwherein R 1 , R 2 , R 3 and R 4 are defined in the specification, comprising the optical resolution of an enamine of the formula n n nwherein R 1 is lower alkyl, in the presence of an optical active resolving agent to form an (S)-enamine salt of the formula n n nwherein RCO 2 − is the conjugate base of the resolving agent. |