Structure-activity relationships were investigated on the tricyclic dihydropyridine (DHP) KATP openers 9-(3-bromo-4-fluorophenyl)-5, 9-dihydro-3 H, 4 H-2, 6-dioxa-4-azacyclopenta [b] naphthalene-1, 8-dione (6) and 10-(3-bromo-4-fluorophenyl)-9, 10-dihydro-1 H, 8 H-2, 7- dioxa-9-azaanthracene-4, 5-dione (65). Substitution off the core of the DHP, absolute stereochemistry, and aromatic substitution were evaluated for KATP channel activity using ...