Journal of Medicinal Chemistry
October 19, 2000
Joseph B. Blair, Deborah Kurrasch‐orbaugh, Danuta Marona‐lewicka et al.
132 citations
Fluorination of hallucinogenic tryptamines generally preserves their affinity and intrinsic activity at 5-HT2A/2C serotonin receptors but reduces affinity at the 5-HT1A receptor, except for one compound. 4-Fluoro-5-methoxy-DMT (compound 6) showed markedly enhanced 5-HT1A receptor affinity (Ki = 0.23 nM) and functional potency, greater than the standard 5-HT1A agonist 8-OH-DPAT, with an ED50 of 0.17 µmol/kg in a drug discrimination assay. Hallucinogen-like activity was attenuated or abolished for all fluorinated analogues. The findings suggest that while 5-HT2A activation is key for hallucinogenic effects, the 5-HT1A receptor may also play a role with tryptamines.
Journal of Medicinal Chemistry
January 1, 1996
Aaron Monte, Danuta Marona‐lewicka, Matthew Parker et al.
106 citations
A series of eight new phenylalkylamine derivatives with conformationally restricted dihydrofuran rings were synthesized and tested in rats. One compound, 7b, substituted for LSD in a drug discrimination assay with an ED50 of 61 nmol/kg and bound to 5-HT2 receptors with nanomolar to subnanomolar affinity, making it among the most potent hallucinogen-like phenylalkylamines reported. All compounds with a hydrophobic substituent para to the alkylamine side chain matched or exceeded the activity of flexible parent compounds. The results suggest the dihydrofuran rings model the active binding conformations of methoxy groups and provide information about agonist binding topography in serotonin 5-HT2 receptors.
Journal of Medicinal Chemistry
September 1, 2002
David E. Nichols, Stewart Frescas, Danuta Marona‐lewicka et al.
89 citations
Lysergic acid amides containing a rigid dimethylazetidine ring—a constrained version of diethylamine—were synthesized and tested for hallucinogenic activity. The (S,S)-(+)-2,4-dimethylazetidine lysergamide showed slightly greater LSD-like behavioral effects in rats than LSD itself and had the highest affinity and functional potency at the serotonin 5-HT(2A) receptor, the presumed target for hallucinogens. Its receptor profile across a panel of screens most closely matched that of LSD. In contrast, the cis- and (R,R)-trans-dimethylazetidine lysergamides were less potent. These results suggest that the N,N-diethyl groups of LSD bind optimally in a conformation different from that seen in the solid state. Incorporating isomeric dialkylazetidines into other molecules may help model active conformations of dialkylamines and dialkylamides.
Journal of Medicinal Chemistry
September 1, 1997
Aaron Monte, Steve R. Waldman, Danuta Marona‐lewicka et al.
89 citations
Conformationally restricted bioisosteres of mescaline's methoxy groups—dihydrobenzofuran (8) and tetrahydrobenzodifuran (9)—were synthesized and tested against mescaline (1) in drug discrimination assays in rats trained to discriminate LSD from saline. Neither 8 nor 9 substituted for LSD: only 50% of rats given 8 and 29% given 9 selected the drug lever, whereas mescaline fully substituted (ED50 = 33.5 mumol/kg). All compounds showed micromolar affinity for 5-HT1A and 5-HT2A receptors in rat brain homogenate, but rank order of affinities at 5-HT2A sites reversed their behavioral potency. At 5-HT2A receptors, 8 and 9 were less efficacious (61% and 45% of maximal response), while all compounds matched serotonin's efficacy at 5-HT2C receptors.
Journal of Medicinal Chemistry
December 1, 1998
Matthew Parker, Danuta Marona‐lewicka, Virginia L. Lucaites et al.
69 citations
A novel (benzodifuranyl)aminoalkane compound was synthesized and evaluated for activity at the 5-HT2A receptor. The compound exhibited extremely potent activity, with a Ki value of 0.4 nM at the human 5-HT2A receptor, making it one of the most potent 5-HT2A receptor agonists reported. It also showed high selectivity over other serotonin receptor subtypes. In rodent behavioral assays, the compound produced effects consistent with 5-HT2A receptor activation, including the head-twitch response in mice. These findings suggest the compound is a valuable tool for studying 5-HT2A receptor function and may have implications for developing new therapeutic agents.
Journal of Medicinal Chemistry
March 1, 1999
Joseph B. Blair, Danuta Marona‐lewicka, Arthi Kanthasamy et al.
63 citations
Two thienopyrrole compounds, designed as structural replacements for the indole ring in N,N-dimethyltryptamine (DMT), were synthesized and tested. Neither compound produced LSD-like effects in rats trained to discriminate LSD or DOI, even at high doses. However, both fully substituted for a 5-HT1A receptor agonist and caused behaviors consistent with 5-HT1A activation, such as serotonin syndrome and salivation. At the 5-HT2A receptor, one compound had twice the affinity of the other, while at 5-HT2B and 5-HT2C receptors the pattern reversed. The thienopyrrole replacement thus failed to mimic DMT's activity at 5-HT2 receptors but enhanced activity at the 5-HT1A receptor, indicating that serotonin receptor subtypes respond differently to subtle electronic changes in the aromatic ring system.
Journal of Medicinal Chemistry
July 1, 2003
James J. Chambers, Jason C. Parrish, Niels Jensen et al.
27 citations
Conformationally constrained tetrahydronaphthofurans were designed to study the optimal shape of the 2-aminoethyl moiety in phenethylamine-type serotonin 5-HT(2A) receptor agonists. In vitro assays showed that benzofuran-containing analogues (6a and 6b) had significantly higher affinity for 5-HT(1A), 5-HT(2A), and 5-HT(2C) receptors than benzodihydrofuran-containing compounds. The most potent compound, 6b, had K(i) values of 2.6 nM at 5-HT(2A) and 1.1 nM at 5-HT(2C) cloned rat receptors. Despite high affinity, these naphthofuran compounds lacked high intrinsic activity at the 5-HT(2A) receptor in the phosphoinositide hydrolysis assay. Compound 6b failed to substitute for LSD in a rat drug discrimination assay, typical for low intrinsic activity compounds. Conformational constraint produced high-affinity partial agonists, but full receptor activation requirements remain unidentified.
Journal of Medicinal Chemistry
February 24, 1998
Matthew Parker, Danuta Marona‐lewicka, Deborah M. Kurrasch et al.
25 citations
Adding a methyl group to the 2 or 5 position of the ring of MDA produces compounds that are more potent and more selective than MDA itself at releasing serotonin in rat brain tissue. The 2-methyl and 5-methyl derivatives were tested in rats trained to distinguish serotonin-releasing drugs from saline, confirming their activity in living animals. These compounds are among the most potent serotonin-releasing agents known and may serve as leads for developing antidepressants that work by releasing serotonin rather than blocking its reuptake.
Journal of Medicinal Chemistry
March 1, 1995
Aaron Monte, Danuta Marona‐lewicka, Arthi Kanthasamy et al.
25 citations
Amides of d-lysergic acid with 3-pentyl, (R)- and (S)-2-pentyl, 2-hexyl, and 2-heptyl substituents were synthesized and tested for LSD-like activity. (R)-lysergamides bound more strongly than (S)-amides to 5-HT2A and 5-HT1A receptors in rat brain tissue. As the amide alkyl chain lengthened from pentyl to heptyl, (R)-isomer affinity for 5-HT2A sites decreased, while affinity for 5-HT1A peaked with (R)-2-hexyllysergamide. In rats trained to discriminate LSD from saline, (R)-alkylamides produced stronger LSD-like effects than (S)-isomers, but longer chains reduced activity, with (R)-hexylamide only partially substituting for LSD. Both isomers acted as potent 5-HT2A agonists, but (R)-pentyllysergamide stimulated phosphoinositide hydrolysis about 20 times more than the (S)-form.
Journal of Medicinal Chemistry
June 21, 2006
Thomas H. Mclean, James J. Chambers, Jason C. Parrish et al.
24 citations
A new molecule, C-(4,5,6-trimethoxyindan-1-yl)-methanamine, was designed based on a computer model of the 5-HT(2A) receptor. This compound showed three times higher affinity and potency than mescaline at the receptor, with equal efficacy. In drug discrimination tests, it fully substituted for LSD and was five times more potent than mescaline. Separating the molecule into its mirror-image forms confirmed the computer predictions: the R-(+) isomer had higher affinity and potency than the S-(-) isomer, with efficacy similar to mescaline at the 5-HT(2A) receptor.
Journal of Medicinal Chemistry
May 1, 1998
Aaron Monte, Danuta Marona‐lewicka, Mechelle M. Lewis et al.
20 citations
A series of racemic naphthofurans were synthesized as hybrid molecules of phenethylamine and tryptamine/ergoline hallucinogens. Although the compounds were expected to have high affinity for serotonin 5-HT2A/2C receptors, they instead showed low affinity for those receptors and unexpected affinity for muscarinic receptors. One compound, 4d, had affinities of 12-33 nM at all muscarinic M1-M5 sites and fully antagonized carbachol at M1 and M2 receptors. The naphthofurans lacked LSD-like activity in a drug discrimination paradigm in rats, indicating that the tricyclic naphthofuran nucleus is not bioisosteric with LSD and that hallucinogenic phenethylamines cannot be directly superimposed on LSD in a common binding orientation, contrary to previous hypotheses.
Journal of Medicinal Chemistry
September 16, 1999
Madina R. Gerasimov, Danuta Marona‐lewicka, Deborah Kurrasch‐orbaugh et al.
15 citations
The R enantiomers of two rigid tryptamine analogues show a 10-20-fold higher affinity for the 5-HT(2A) receptor than the S enantiomers, with no distinction based on the position of the oxygen group. The R enantiomers of both compounds have nearly identical affinities at the agonist-labeled receptor, while racemic versions of related compounds have about one-tenth the affinity. In rats trained to discriminate LSD or DOI from saline, the R enantiomers are about equipotent to DOI but about 10-fold less potent than LSD. One compound produced only partial substitution even at a dose nearly 5-fold higher than for the active R enantiomer. The results suggest these compounds would possess LSD-like psychopharmacology in humans.