title: Synthesis and calcium channel antagonist activity of 3-arylmethyl 5-isopropyl 1,4-dihydro-2,6-dimethyl-4-(pyridyl)-3,5-pyridinedicarboxylates.
abstract: Unsymmetrical aryl(heteroaryl)methyl isopropyl ester analogues of nifedipine, in which the 2-nitrophenyl group at C-4 is replaced by a 2- or 3-pyridyl substituent, were synthesized and evaluated as calcium-channel antagonists using guinea pig ileal longitudinal smooth muscle. The point of attachment of the C-4 pyridyl substituent was a determinant of activity where the relative potency order was 2-pyridyl greater than 3-pyridyl. Within the C-4 2-pyridyl series of compounds, and electronegative substituent such as a trifluoromethyl or bromo at the 4 position of the benzyl ester substituent or a nitrogen atom at the 1 position of a 4-pyridylmethyl ester substituent, enhanced activity relative to the unsubstituted benzyl ester analogue. In contrast, in the C-4 3-pyridyl class of compounds, a variety of aryl(heteroaryl)methyl ester substituents did not alter potency to any significant extent. A number of compounds in the C-4 2-pyridyl series possessing 4-pyridylmethyl, 4-trifluoromethylbenzyl, 4-bromobenzyl, and 3-pyridylmethyl ester substituents were approximately equipotent to nifedipine. The aryl(heteroaryl)methyl ester and C-4 2-pyridyl substituents therefore appear to provide important interdependent contributions to calcium-channel antagonist activity.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.
authors.forename: M R
authors.initials: MR
authors.lastname: Akula
authors.forename: W C
authors.initials: WC
authors.lastname: Matowe
authors.forename: M W
authors.initials: MW
authors.lastname: Wolowyk
authors.forename: E E
authors.initials: EE
authors.lastname: Knaus
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000138:chemical synthesis* / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: D002121:Calcium Channel Blockers; D009543:Nifedipine