p-Dimethoxy-substituted trans-octahydrobenzo[f]- and -[g]quinolines: synthesis and assessment of dopaminergic agonist effects.

The N-n-propyl homologues of the title compounds were prepared for further assessment of the ability of the "p-dimethoxy" moiety to confer dopaminergic agonism upon a variety of ring systems. Both the angularly and the linearly annulated trans-benzoquinoline ring derivatives displayed prominent DA2 dopaminergic effects on the peripheral sympathetic nerve terminal and displayed postjunctional dopamine receptor agonist properties in the striatum. It is speculated that the angular octahydrobenzo[f]quinoline derivative (but not the linear octahydrobenzo[g]quinoline derivative) may owe its dopamine-like effects to metabolic activation phenomena. In contrast, the cis-fused isomer of the angularly annulated benzoquinoline was inactive, as was the simple benzene derivative N,N-di-n-propyl-beta-(2,6-dimethoxyphenyl)ethylamine.