FPL 64176: The effect of the chain length separating the two aryl groups on calcium agonist activity

Analogs of the L-type calcium channel agonist FPL 64176 (5) were prepared in which the chain length separating the two aryl moieties was varied between zero and four. FPL 64176 (5) and phenethyl derivative 19 were the most potent compounds tested, displaying EC50 values for enhancing calcium influx into GH3 cells of 1−2×10−7 M.