title: Synthesis and preliminary pharmacological evaluation of asymmetric chloroquine analogues.
abstract: 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 than the less lipophilic (S)- and (R)-hydroxychloroquines (3 and 4, respectively) when tested against KCl- or acetylcholine-induced contractions of the isolated mouse ileum. A membrane stabilizing mechanism of action for the chloroquine analogues is proposed since neither cellular toxicity nor calcium antagonism plays a role in the spasmolytic action of these compounds. Although compounds 1-4 also inhibited PGF2 alpha-induced contractions of the ileum, 1 was significantly more potent than 2; the latter in turn was equipotent to 3 and 4. It is tentatively proposed that 1 may possess stereoselective affinity for the PGF2 alpha receptor in the ileum. This observation may be further exploited to obtain more selective profiles of biological activity through molecular manipulation.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002738:Chloroquine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D010276:Parasympatholytics; D011461:Prostaglandins F, Synthetic / Q000494:pharmacology; D011982:Receptors, Prostaglandin / Q000187:drug effects; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D010276:Parasympatholytics; D011461:Prostaglandins F, Synthetic; D011982:Receptors, Prostaglandin; D002738:Chloroquine; D000109:Acetylcholine