Derivatives of 4-(2-N,N-Di-n-propylaminoethyl)-5-hydroxyindole: Synthesis and Pharmacological Effects
Abstract5-Methoxy-l-methyl-4-(2-N,N-di-n-propylaminoethyl)indole (12) was synthesized from 5-hydroxyindole by a multistep synthesis. This target compound was designed as a bioisostere of “p-dimethoxy” catechol congeners of dopaminergic agonists derived from a variety of ring systems, in some of which p-dimethoxy-substituted systems are potent, active dopaminergic agonists. To complete the indole series, all possible combinations of N- and O-demethylated derivatives of 12 were prepared and were also evaluated pharmacologically. All members of this indole-derived series showed a low order of cardiovascular activity, which appeared to be independent of dopamine receptors. The lack of dopaminergic activity of 12 is cited as yet another example of the unpredictable effect of replacement of the catechol moiety of a dopaminergic agonist with a p-dimethoxy moiety.
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.
The Total Synthesis of Lysergic Acid
in the ultracentrifuge, as are polysaccharides generally. With respect to immunological homogeneity it has been established by several investigators that proteins which are non-homogeneous in the ultracentrifuge, electrophoretically and in amino acid composition may be immunochemically uniform. The relationship of amino acid composition to specificity among the blood group substances is not clear from the data presented. Work on the inhibition by oligosaccharides of the precipitation of blood group substances with specific antibody suggests that the carbohydrate presents binding sites for the immunological reaction. In view of the general similarity of amino acid composition, it is