title: Synthesis and calcium channel antagonist activity of new 1,4-dihydropyridine derivatives containing lipophilic 4-imidazolyl substituents.
abstract: A group of cycloalkyl and aryl ester analogues of nifedipine (CAS 21829-25-4), in which the ortho-nitrophenyl group at position 4 is replaced by a 2-phenyl-4(5)-imidazolyl substituent, were synthesized and evaluated as calcium channel antagonist using the high K+ contraction of guinea-pig ileal smooth muscle. The results for the symmetrical esters in cycloalkyl and aryl esters showed that increasing the length of the methylene chain in C3 and C5 ester substituents (from n = 0 to n = 3) increased activity. A comparison of the effect of cyclohexyl relative to phenyl substituent showed that cyclohexyl derivatives were more active than phenyl derivatives. In contrast to symmetrical derivatives, comparison of the activities of asymmetrical esters showed that phenyl derivatives were more active than cycloalkyl derivatives. The results demonstrate that compounds 5a, 8a, 8l and 8n had similar activity to and compounds 5b, 5c, 5d and 5i were more active than the reference drug nifedipine. The structure-activity data indicate that the 4-(2-phenyl-4(5)-imidazolyl) moiety is a bioisoester of the o-nitro group of nifedipine.
authors.affiliation: Department of Medicinal Chemistry and Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Latifeh
authors.initials: L
authors.lastname: Navidpour
authors.forename: Ramin
authors.initials: R
authors.lastname: Miri
authors.forename: Abbas
authors.initials: A
authors.lastname: Shafiee
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000138:chemical synthesis* / Q000494:pharmacology*; D004095:Dihydropyridines / Q000138:chemical synthesis* / Q000494:pharmacology*; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D013329:Structure-Activity Relationship
chemical_list: D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D007202:Indicators and Reagents