2,5-Di-methyl-bufo-tenine and 2,5-di-methyl-bufo-teni-dine: novel derivatives of natural tryptamines found in Bufo alvarius toads

N-Cyclo-hexyl-tryptamine: freebase, bromide and fumarate

The solid-state structures of N-cyclo-hexyl-tryptamine (I) {systematic name: N-[2-(1H-indol-3-yl)eth-yl]cyclo-hexa-namine}, C16H22N2, and two of its salts, N-cyclo-hexyl-tryptammonium bromide (II) {systematic name: N-[2-(1H-indol-3-yl)eth-yl]cyclo-hexa-naminium bromide}, C16H23N2 +·Br-, and N-cyclo-hexyl-tryptammonium fumarate (III) (systematic name: bis-{N-[2-(1H-indol-3-yl)eth-yl]cyclo-hexa-naminium} (2E)-but-2-enedioate), 2C16H23N2 +·C4H2O4 2-, were determined by single-crystal X-ray diffraction. The freebase compound forms infinite chains along [010] through N-H⋯N hydrogen bonds. The bromide salt is held together by N-H⋯Br inter-actions in two-dimensional sheets along (001). The fumarate salt is held together in infinite three-dimensional frameworks by N-H⋯O hydrogen bonds.

Synthesis, Structural Characterization, and Pharmacological Activity of Novel Quaternary Salts of 4-Substituted Tryptamines

Aeruginascin (4-phosphoryloxy-N,N,N-trimethyltryptammonium) is an analogue of psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine) that has been identified in several species of psilocybin-containing mushrooms. Our team previously reported the synthesis, structural characterization, and biological activity of the putative metabolite of aeruginascin (4-hydroxy-N,N,N-trimethyltryptammonium; 4-HO-TMT) and its potential prodrug (4-acetoxy-N,N,N-trimethyltryptammonium; 4-AcO-TMT). Here, we report the synthesis, structural characterization, and pharmacological activity of several quaternary tryptammonium analogues of 4-HO-TMT and 4-AcO-TMT, namely, 4-hydroxy-N,N-dimethyl-N-ethyltryptammonium (4-HO-DMET), 4-hydroxy-N,N-dimethyl-N-n-propyltryptammonium (4-HO-DMPT), and 4-hydroxy-N,N-dimethyl-N-isopropyltryptammonium (4-HO-DMiPT), as well as their hypothesized prodrugs 4-acetoxy-N,N-dimethyl-N-ethyltryptammonium (4-AcO-DMET), 4-acetoxy-N,N-dimethyl-N-n-propyltryptammonium (4-AcO-DMPT), and 4-acetoxy-N,N-dimethyl-N-isopropyltryptammonium (4-AcO-DMiPT). Compounds were synthesized using established methods, and structures were characterized by single-crystal X-ray diffraction. Test compounds were screened for in vitro pharmacological activity at a variety of receptors and transporters to determine potential targets of action. None of the compounds exhibited measurable affinity for the serotonin 2A receptor (5-HT2A), but several analogues had low micromolar affinity (K i) for the serotonin 1D receptor (5-HT1D) and serotonin 2B receptor (5-HT2B), where they appeared to be weak partial agonists with low micromolar potencies. Importantly, 4-HO-DMET, 4-HO-DMPT, and 4-HO-DMiPT displayed sub-micromolar affinity for the serotonin transporter (SERT; 370-890 nM). The same 4-hydroxy analogues had low to sub-micromolar potencies (IC50) for inhibition of 5-HT uptake at SERT in transfected cells (3.3-12.3 μM) and rat brain tissue (0.31-3.5 μM). Overall, our results show that quaternary tryptammonium analogues do not target 5-HT2A sites, suggesting the compounds lack psychedelic-like subjective effects. However, certain 4-hydroxy quaternary tryptammonium analogues may provide novel templates for exploring structure-activity relationships for selective actions at SERT.

5-Meth-oxy-N,N-di-n-propyl-tryptamine (5-MeO-DPT): freebase and fumarate

The solid-state structures of the synthetic psychedelic 5-meth-oxy-N,N-di-n-propyl-tryptamine (5-MeO-DPT) {systematic name: N-[2-(5-meth-oxy-1H-indol-3-yl)eth-yl]-N-propyl-propan-1-amine}, C17H25N2O, and its fumarate salt, bis-(5-meth-oxy-N,N-di-n-propyl-tryptammonium) fumarate (systematic name: bis-{N-[2-(5-meth-oxy-1H-indol-3-yl)eth-yl]-N-propyl-propan-1-aminium} but-2-ene-dio-ate), 2C17H25N2O+·C4H2O4 2-, are reported. The freebase has a single tryptamine mol-ecule in the asymmetric unit. The mol-ecules are linked together by N-H⋯N hydrogen bonds in zigzag chains along the [010] direction. The fumarate salt has a single tryptammonium cation and half of a fumarate dianion in the asymmetric unit. The tryptammonium and fumarate ions are held together in one-dimensional chains by a series of N-H⋯O hydrogen bonds. These chains are combinations of R 4 4(22) rings, and C 2 2(14) and C 4 4(28) parallel chains along [001].

'Foxtrot' fumarate: a water-soluble salt of N,N-di-allyl-5-methoxytryptamine (5-MeO-DALT)

The title compound, bis-(N,N-diallyl-5-meth-oxy-tryptammonium) (5-MeO-DALT) fumarate (systematic name: bis-{N-[2-(5-meth-oxy-1H-indol-3-yl)eth-yl]- N-(prop-2-en-1-yl)prop-2-en-1-aminium} (E)-but-2-enedioate), 2C17H23N2O+·C4H2O4 2-, has a single tryptammonium cation and half of a fumarate dianion in the asymmetric unit. The tryptammonium and fumarate ions are held together in one-dimensional chains by a series of N-H⋯O hydrogen bonds. These chains are combinations of R 4 4(22) rings, and C 2 2(14) and C 4 4(28) parallel chains along [111].

Bufotenidinium iodide

The structure of the natural product bufotenidine is reported as its iodide salt.

The title compound, 5-hy­droxy-N,N,N-tri­methyl­tryptammonium (5-HTQ) iodide {systematic name: [2-(5-hy­droxy-1H-indol-3-yl)eth­yl]tri­methyl­aza­nium iodide}, C₁₃H₁₉N₂O⁺·I⁻, has a single tryptammonium cation and one iodide anion in the asymmetric unit. The ions are held together by N—H⋯I and O—H⋯I hydrogen bonds in infinite chains along [100].