Partial lysergamide

Partial or simplified ergolines and lysergamides are analogues of ergolines and lysergamides like LSD in which one or more atoms or bonds, for instance within the ergoline ring system, have been removed.^[1][2][3] Additional substitutions may also be added, for instance on the A ring of the ergoline nucleus.^[1][2][3] It is notable that the ergoline ring system contains embedded tryptamine and phenethylamine moieties within its structure, and so some partial ergolines are simple tryptamines, cyclized tryptamines, simple phenethylamines, and/or cyclized phenethylamines.

In terms of pharmacology, partial lysergamides include serotonin and dopamine receptor agonists. Some, like NDTDI, DEMPDHPCA, DEIMDHPCA, and LPH-5, are serotonin 5-HT_2A receptor agonists and have psychedelic-like and/or psychoplastogenic effects. Some, like 8-OH-DPAT and LY-178210, are selective serotonin 5-HT_1A receptor agonists. Others, like rotigotine and RU-28251, are dopamine D₂-like receptor agonists. Partial ergolines have generally shown markedly reduced potency in terms of hallucinogen-like effects compared to LSD.^[4]

Examples of partial lysergamides that are simple tryptamines include N-DEAOP-NMT and 5-MeO-N-DEAOP-NMT and examples that are simple phenethylamines include N-DEAOP-NMPEA and 25D-NM-NDEAOP. An example of a cyclized tryptamine-like compound is DEIMDHPCA while examples of cyclized phenethylamines include DEMPDHPCA, DEMPDHPCA-2C-D, and LPH-5. Some, like 8-OH-DPAT and rotigotine, are 2-aminotetralins. Others, like NDTDI and LY-178210, are tricyclic compounds that still contain both tryptamine and phenethylamine components. Tochergamine is a simplified analogue of ergometrine that was clinically investigated as an oxytocic agent but was abandoned.