Geometry−Affinity Relationships of the Selective Serotonin Receptor Ligand 9-(Aminomethyl)-9,10-dihydroanthracene
摘要:
With the exception of its two aromatic rings and basic nitrogen atom, 9-(aminomethyl)-9,10-dihydroanthracene (AMDA; 1) is remarkably devoid of the pharmacophore features usually associated with high-affinity receptor ligands such as the heteroatom hydrogen bonding features of the endogenous ligand serotonin. AMDA does contain a phenylethylamine skeleton within a tricyclic ring system, and the presence of the second aromatic group is necessary for optimal receptor affinity. The structural requirements for the binding of AMDA at 5-HT2A receptors were investigated with respect to the geometric relationship between the two aromatic rings. It appears that the geometry of the AMDA parent is in the optimal range for fold angle between aromatic moieties. Evaluation of conformationally constrained derivatives of AMDA suggests that a chain extended trans, gauche form is most likely responsible for high affinity.
Reductive Photocarboxylation of Phenanthrene: A Mechanistic Investigation
摘要:
Irradiation of a solution of phenanthrene (PHN) in DMSO saturated with CO2 in the presence of N,N-dimethylaniline (DMA) produced 9,10-dihydrophenanthrene-9-carboxylic acid(1) in 55% yield, trans-9,10-dihydrophenanthrene-9,10-dicarboxylic acid (2) in 11% yield, a trace of phenanthrene-9-carboxylic acid (3), and a trace of 10-[p-(N,N-dimethylamino)phenyl]-9,10-dihydrophenanthrene-9-carboxylic acid (5), Addition of cumene, a hydrogen donor, or water, a proton donor, decreased the yield of 2, while addition of certain salts increased its yield, 9-Carboxy-9,10-dihydrophenanthr-10-yl, generated by irradiation of phenanthrene-9-carboxylic acid in the presence of DMA, is proposed to be an intermediate in the formation of the acids,,The quantum yield for the formation of 2 increased to a maximum of 0.13 with increasing light intensity. High CO2 concentrations in DMSO changed the reaction pathway, greatly reducing the yields of 1 and 2, and phenanthrene-9-carboxylic acid (3) and 10-[p-(N,N-dimethylamino)phenyl]-9,10-dihydrophenanthrene-9-carboxylic acid (5) were formed instead. On the basis of these results reduction of 9-carboxy-9,10-dihydrophenanthr-10-yl with the phenanthrene radical anion is proposed to be a step in the mechanism accounting for trans-9,10-dihydrophenanthrene-9,10-dicarboxylic acid formation, Transient spectroscopic evidence in support of this proposal is presented.
作者:Qing-Yuan Meng、Tobias E. Schirmer、Anna Lucia Berger、Karsten Donabauer、Burkhard König
DOI:10.1021/jacs.9b05360
日期:2019.7.24
the hydrogen atom transfer catalyst to afford a benzylic radical that accepts an electron from the reduced form of 2,3,4,6-tetra(9H-carbazol-9-yl)-5-(1-phenylethyl)benzonitrile generated in situ. The resulting benzylic carbanion reacts with CO2 to generate the corresponding carboxylic acid after protonation. The reaction proceeded without the addition of any sacrificial electron donor, electron acceptor