Lysergic acid ethyl-2-hydroxyethylamide

Lysergic acid ethyl-2-hydroxyethylamide
Clinical data
Other names	LEO; N-Ethyl-N-(2-hydroxyethyl)-6-methyl-9,10-didehydroergoline-8β-carboxamide
Drug class	Serotonin receptor modulator
ATC code	None;
Identifiers
	IUPAC name (6aR,9R)-N-ethyl-N-(2-hydroxyethyl)-7-methyl-6,6a,8,9-tetrahydro-4H-indolo[4,3-fg]quinoline-9-carboxamide;
CAS Number	65527-58-4;
PubChem CID	53938953;
ChemSpider	128919021;
Chemical and physical data
Formula	C20H25N3O2
Molar mass	339.439 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES CCN(CCO)C(=O)[C@H]1CN([C@@H]2CC3=CNC4=CC=CC(=C34)C2=C1)C;
	InChI InChI=1S/C20H25N3O2/c1-3-23(7-8-24)20(25)14-9-16-15-5-4-6-17-19(15)13(11-21-17)10-18(16)22(2)12-14/h4-6,9,11,14,18,21,24H,3,7-8,10,12H2,1-2H3/t14-,18-/m1/s1; Key:IWLBOZQDDPXOIT-RDTXWAMCSA-N;

Lysergic acid ethyl-2-hydroxyethylamide (LEO) is a serotonin receptor modulator of the lysergamide family related to lysergic acid diethylamide (LSD).^[1]^[2]^[3]^[4] It is the derivative of LSD in which one of its N-ethyl groups of LSD has been hydroxylated at the end or 2 position.^[1]^[2] It is also an active metabolite of LSD including in humans.^[1]^[2]^[5] LEO shows potent antiserotonergic activity and oxytocic activity in the isolated rat uterus in vitro similarly to LSD.^[3] In addition, it produced hyperthermia in rabbits in vivo similarly to LSD.^[4] LEO was first described in the scientific literature by 1974.^[3]

^ ^a ^b ^c Nichols DE (October 2018). "Dark Classics in Chemical Neuroscience: Lysergic Acid Diethylamide (LSD)" (PDF). ACS Chemical Neuroscience. 9 (10): 2331–2343. doi:10.1021/acschemneuro.8b00043. PMID 29461039.
^ ^a ^b ^c Passie T, Halpern JH, Stichtenoth DO, Emrich HM, Hintzen A (2008). "The pharmacology of lysergic acid diethylamide: a review". CNS Neuroscience & Therapeutics. 14 (4): 295–314. doi:10.1111/j.1755-5949.2008.00059.x. PMC 6494066. PMID 19040555.
^ ^a ^b ^c Hashimoto H, Hayashi M, Nakahara Y, Niwaguchi T, Ishii H (October 1977). "Actions of D-lysergic acid diethylamide (LSD) and its derivatives on 5-hydroxytryptamine receptors in the isolated uterine smooth muscle of the rat". European Journal of Pharmacology. 45 (4): 341–348. doi:10.1016/0014-2999(77)90273-4. PMID 923645.
^ ^a ^b Hashimoto H, Hayashi M, Nakahara Y, Niwaguchi T, Ishii H (August 1977). "Hyperthermic effects of D-lysergic acid diethylamide (LSD) and its derivatives in rabbits and rats". Archives Internationales de Pharmacodynamie et de Therapie. 228 (2): 314–321. PMID 303504.
^ Herian M (2022). "Pharmacological Action of LSD: LSD Effect on the Neurotransmission and Animal Behavior". Handbook of Substance Misuse and Addictions. Cham: Springer International Publishing. pp. 2457–2475. doi:10.1007/978-3-030-92392-1_131. ISBN 978-3-030-92391-4. Retrieved 8 June 2025.

[Nichols_2018-1] Nichols DE (October 2018). "Dark Classics in Chemical Neuroscience: Lysergic Acid Diethylamide (LSD)" (PDF). ACS Chemical Neuroscience. 9 (10): 2331–2343. doi:10.1021/acschemneuro.8b00043. PMID 29461039.

[Passie_2008-2] Passie T, Halpern JH, Stichtenoth DO, Emrich HM, Hintzen A (2008). "The pharmacology of lysergic acid diethylamide: a review". CNS Neuroscience & Therapeutics. 14 (4): 295–314. doi:10.1111/j.1755-5949.2008.00059.x. PMC 6494066. PMID 19040555.

[Hashimoto_1977-3] Hashimoto H, Hayashi M, Nakahara Y, Niwaguchi T, Ishii H (October 1977). "Actions of D-lysergic acid diethylamide (LSD) and its derivatives on 5-hydroxytryptamine receptors in the isolated uterine smooth muscle of the rat". European Journal of Pharmacology. 45 (4): 341–348. doi:10.1016/0014-2999(77)90273-4. PMID 923645.

[Hashimoto_1977a-4] Hashimoto H, Hayashi M, Nakahara Y, Niwaguchi T, Ishii H (August 1977). "Hyperthermic effects of D-lysergic acid diethylamide (LSD) and its derivatives in rabbits and rats". Archives Internationales de Pharmacodynamie et de Therapie. 228 (2): 314–321. PMID 303504.

[Herian_2022-5] Herian M (2022). "Pharmacological Action of LSD: LSD Effect on the Neurotransmission and Animal Behavior". Handbook of Substance Misuse and Addictions. Cham: Springer International Publishing. pp. 2457–2475. doi:10.1007/978-3-030-92392-1_131. ISBN 978-3-030-92391-4. Retrieved 8 June 2025.

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