UCD0179

Admitted on a publication

This compound is in the archive because a named paper characterized it. Basargin, Domokosa, Hennessey et al., Proceedings of the National Academy of Sciences 2026 prints it as UCD0179 (PMID 42709856). It reports Ki at psychLight2 (Table S1, Fig. 2A); EC50 and Emax of Gq activation at 5-HT2A, 5-HT2B and 5-HT2C (Table S2, Figs. 3-5); EC50 and Emax of beta-arrestin2 recruitment at 5-HT2A (Table S3); EC50 and Emax of GoB activation at D2 (Table S4, Fig. S15); head-twitch dose-response in mice at 0.1, 1 and 10 mg/kg (Fig. 7B), which it did not induce at any dose; stability of a DMSO stock over a week at room temperature (Fig. S14A); failure to block a 5-MeO-DMT-induced head twitch on 15-minute pretreatment at 10 mg/kg (Fig. S14B); and brain and plasma concentrations at 2, 5, 15 and 30 min after 10 mg/kg IP (Fig. S14D), which the paper uses to argue the absent head twitch is pharmacokinetic rather than pharmacological.

ChEMBL holds no molecule whose InChIKey skeleton matches GDCMLRPQENDWLG. The paper is the only source there is, and it is the most potent and most efficacious 5-HT2A agonist in the series it reports.

Identity This entry is the one place in the file where the name checked is not the name of the record. The SI never names UCD0179's free base — it calls it 'UCD0179 freebase' and gives its Rf, NMR, HRMS and IR — and names only the salt it isolated: '3-(diethylcarbamoyl)-5-(1H-indol-4-yl)-1-methyl-1,2,3,6-tetrahydropyridin-1-ium 4-methylbenzenesulfonate' (Experimental Procedures for the Synthesis of UCD0179 and UCD0120, p. S40). So the cation is what the paper names and the cation is what is checked. OPSIN reads it as GDCMLRPQENDWLG-UHFFFAOYSA-O; PubChem gives CID 156277796 the InChIKey GDCMLRPQENDWLG-UHFFFAOYSA-N. Those differ in the final character of the standard InChIKey and nowhere else — same skeleton block, same stereo block — and that character is the protonation indicator. `identity_name_is_protonated` declares the relation and the ingest checks it rather than taking it on trust; a difference in either of the other two blocks is still a refusal. Holding the free base of the salt a paper handled is what every record in this archive does, and this is that convention stated once per record instead of asserted in prose. Formula C19H25N3O, and the SI's HRMS is [M+H]+ calcd. 312.2070 for C19H26N3O+, found 312.2082. PubChem lists one name for the CID, SCHEMBL23249306, and titles it 'N,N-diethyl-5-(1H-indol-4-yl)-1-methyl-3,6-dihydro-2H-pyridine-3-carboxamide'.

Read Two files, both read in full. The article as published (PNAS 2026;123(38):e2603412123, open access under CC BY): Significance, abstract, Introduction, all of Results, Discussion, Methods, the captions of Figs. 1-8, and the reference list. And the Supporting Information (Appendix 01, pnas.2603412123.sapp.pdf, 144 pp., retrieved from PNAS on 2026-09-09): the synthetic schemes S1-S9 and S12, the Experimental Procedures section carrying the systematic name, salt form, NMR, LC-MS, HRMS, IR and UHPLC purity for every ergolog, Tables S1-S5, and the pharmacology methods 'Radioligand Binding Assays', '5-HT2 Gq dissociation BRET Assays' and 'beta-Arrestin2 Recruitment BRET Assays'. The SI is what fixes each of the paper's compound codes to a molecule, and without it none of this would be admissible.