β-Carbolines as inverse agonistic benzodiazepine receptor ligands. 2. Synthesis and in vitro and in vivo binding of some new 6-amino- and 6-fluoro-β-carboline-3-carboxylates
摘要:
Six new 6-fluoro-beta-carboline-3-carboxylates (3a-f) with their related 6-amino analogues (2a-f) are described and their in vitro and in vivo capabilities to bind to rat cerebral cortex 'benzodiazepine receptors' checked by radioreceptor assay (RRA). For some of the derivatives, the tests were also accomplished in the absence and presence of 10 mu M GABA, whereby an inverse agonistic activity resulted. Their IC50 for [H-3]flunitrazepam displacement were in the 10(-9)-10(-12) molar range. The same compounds, with the exception of the hydroxylated compounds 2e, 2f, 3e and 3f, crossed the blood-brain barrier in the rat, generally giving rise to higher concentrations in the brain (ng/g) than in the plasma(ng/ml). The synthetic pathway preferred here allows a rapid fluorine incorporation in this moiety and an easy isolation of the fluorinated compounds.
Synthesis of 6-substituted .beta.-carbolines that behave as benzodiazepine receptor antagonists or inverse agonists
作者:Timothy J. Hagen、Phil Skolnick、James M. Cook
DOI:10.1021/jm00387a033
日期:1987.4
The synthesis of the first beta-carboline, 6-(benzylamino)-beta-carboline (1c), to be devoid of a substituent at the 3-position and that still binds to benzodiazepine receptors with potent affinity is described. Furthermore, 1c proved to be a partial inverse agonist when tested in mice. Addition of the benzylamino group at the 6-position of the beta-carboline nucleus is primarily responsible for the activity of beta-carbolines 1b and 1c. The importance of the Nb-nitrogen atom for binding affinity was also demonstrated since 3-(benzylamino)carbazole (6) exhibited little or no affinity for benzodiazepine receptors in vitro, in contrast to the activity of 1c.