2-Iodo-LSD

2-Iodo-LSD (IOL) is a putatively non-hallucinogenic serotonin receptor modulator of the lysergamide family related to 2-bromo-LSD (BOL-148) and lysergic acid diethylamide (LSD).^[1][2][3] It is the 2-iodo derivative of LSD.^[1][2][3]

2-Iodo-LSD

Clinical data
Other names	Iodo-LSD; Iodine-LSD; IOL; 2-Iodolysergic acid diethylamide; 2-Iodo-N,N-diethyllysergamide; N,N-Diethyl-2-iodo-6-methyl-9,10-didehydroergoline-8β-carboxamide
Drug class	Serotonin receptor modulator; Non-hallucinogenic serotonin 5-HT2A receptor modulator
ATC code	None
Identifiers
IUPAC name (6aR,9R)-N,N-diethyl-5-iodo-7-methyl-6,6a,8,9-tetrahydro-4H-indolo[4,3-fg]quinoline-9-carboxamide
CAS Number	3712-25-2
PubChem CID	151142
ChemSpider	133214
ChEMBL	ChEMBL433352
CompTox Dashboard (EPA)	DTXSID30958287
Chemical and physical data
Formula	C20H24IN3O
Molar mass	449.336 g·mol−1
3D model (JSmol)	Interactive image
SMILES CCN(CC)C(=O)[C@H]1CN([C@@H]2CC3=C(NC4=CC=CC(=C34)C2=C1)I)C
InChI InChI=1S/C20H24IN3O/c1-4-24(5-2)20(25)12-9-14-13-7-6-8-16-18(13)15(19(21)22-16)10-17(14)23(3)11-12/h6-9,12,17,22H,4-5,10-11H2,1-3H3/t12-,17-/m1/s1 Key:OBCUQRYIGTWROI-SJKOYZFVSA-N

Pharmacology

The drug shows high affinity for the serotonin 5-HT₂ receptors and also shows affinity for other serotonin receptors as well as for the dopamine and adrenergic receptors.^[4][5] In contrast to LSD, but similarly to 2-bromo-LSD, 2-iodo-LSD is predominantly antagonistic at the serotonin 5-HT_2A and 5-HT_2C receptors and is described as non-hallucinogenic.^[1][2][3][6] The drug has about 57.4% of the antiserotonergic activity of LSD in the isolated rat uterus in vitro, whereas 2-bromo-LSD has about 103% of LSD's potency in this assay.^[7][8][9]

Radiolabeling

[¹²⁵I]2-Iodo-LSD, a radiolabeled analogue of 2-iodo-LSD, has been used as a radioligand for serotonin 5-HT₂ receptors.^[1][2][10] In addition, radiolabeled derivatives of 2-iodo-LSD, such as 1-methyl-2-[¹²⁵I]iodo-LSD ([¹²⁵I]-MIL) and 1-ethyl-2-[¹²⁵I]iodo-LSD ([¹²⁵I]-EIL), have been developed for use as presumably non-hallucinogenic agents in imaging of serotonin receptors.^[11][12]

History

2-Iodo-LSD was described in the scientific literature by Albert Hofmann and colleagues by 1956.^{[13][14][8][7]}

See also

• Substituted lysergamide
• 2-Bromo-LSD (BOL-148)
• 2-Oxo-LSD