Rigid congeners of dopamine based on octahydrobenzo[f]quinoline: peripheral and central effects

A series of cis- and trans-dihydroxycotahydrobenzo[f]quinoline congeners of dopamine has been prepared, in which the N substitutent is H, ethyl, or n-propyl. The trans isomers include the dopamine moiety held rigidly in an antiperiplanar diposition which is believed to be necessary for certian central and peripheral dopaminergic effects. The cis isomers are flexible molecules; the dopamine moiety lacks conformational integrity and it can exist in a conformation which is believed not to favor dopaminergic activity. The trans series of compounds was shown to possess a high level of central and peripheral dopaminergic effects, whereas the cis series was of low activity or was inert. These data further support previous proposals concerning stereochemical requirements for certain dopaminergic agonist activity.