Octahydrobenzo[g]quinolines: potent dopamine agonists which show the relationship between ergolines and apomorphine

A synthesis of all four diastereoisomeric 3-(tert-butoxycarbonyl)-1,6-dimethoxyoctahydrobenzo[g]quinolines 13a-d is presented. The two trans isomers 13b and 13c have been converted to tricyclic analogues 20 (CV 205-502) and 26 (205-503) of the potent dopaminomimetic ergolines CQ 32-084 and pergolide, respectively. These two compounds combine the essential moiety of apomorphine with the important 8-substituents of ergolines. Preliminary pharmacological evaluation of 20 and 26 suggests that these novel dopamine agonists combine the specificity of apomorphine with the potency, long duration of action, and good oral activity of the ergolines.