Asymmetric chloroquine analogues (1-4) were prepared of known absolute configuration in order to assess stereochemical influences on selected biological activities. Since chloroquine has been shown to possess spasmolytic properties, analogues 1-4 were tested for similar pharmacological effects on smooth-muscle contraction. The (S)-and (R)- chlorochloroquine enantiomers (1 and 2, respectively) were more potent antispasmodics ...