The present invention relates to the preparation of the (S)-(-)-amlodipine
and (R)-(+)-amlodipine by means of enantiomeric separation of racemic
amlodipine mixture, in which, L- or D-tartaric acid is used as resolution
agent, and organic solvent containing 2-butanone is used as solvent. The
2-butanone used in the present invention has the advantage of low boiling
point, low toxicity, litter pollution, and the method is suitable for
large-scaled production.