PNU-181731

PNU-181731
Identifiers
	IUPAC name 2,3,4,5-tetrahydro-1H-[1,4]diazepino[1,7-a]indole;
CAS Number	364344-56-9 ;
PubChem CID	9794092 ;
ChemSpider	7969859 ;
UNII	UVL6VJD7YC ;
CompTox Dashboard (EPA)	DTXSID201045564 ;
Chemical and physical data
Formula	C12H14N2
Molar mass	186.258 g·mol−1
3D model (JSmol)	Interactive image ;
	SMILES C12=CC=CC=C1N3C(CCNCC3)=C2;
	InChI InChI=1S/C12H14N2/c1-2-4-12-10(3-1)9-11-5-6-13-7-8-14(11)12/h1-4,9,13H,5-8H2; Key:XORPZYQOYUSNCQ-UHFFFAOYSA-N;

Last updated November 28, 2025

PNU-181731 is a drug which acts as an agonist at serotonin 5-HT₂ receptors,^[1]^[2] with strongest binding affinity for the 5-HT_2C subtype at 4.8nM, and weaker 5-HT_2A affinity of 18nM. It has anxiolytic effects in animal studies with around one tenth the potency of alprazolam and no significant ataxia or other side effects noted.^[3] It is a cyclized isotryptamine related to the ibogalogs.

References

↑ US 6734301,Ennis ME, et al.,"2,3,4,5-Tetrahydro-1H-[1,4]diazepino[1,7-a]indole compounds.",published May 11, 2004, assigned to Pharmacia and Upjohn Co Inc
↑ US 8158617,Shirai J, et al.,"Fused heterocyclic compound and use thereof.",published April 17, 2012, assigned to Takeda Pharmaceutical Co Ltd
↑ Ennis MD, Hoffman RL, Ghazal NB, Olson RM, Knauer CS, Chio CL, et al. (July 2003). "2,3,4,5-tetrahydro- and 2,3,4,5,11,11a-hexahydro-1H-[1,4]diazepino[1,7-a]indoles: new templates for 5-HT(2C) agonists". Bioorganic & Medicinal Chemistry Letters. 13 (14): 2369–72. doi:10.1016/S0960-894X(03)00403-7. PMID 12824036.

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[1] US 6734301,Ennis ME, et al.,"2,3,4,5-Tetrahydro-1H-[1,4]diazepino[1,7-a]indole compounds.",published May 11, 2004, assigned to Pharmacia and Upjohn Co Inc

[2] US 8158617,Shirai J, et al.,"Fused heterocyclic compound and use thereof.",published April 17, 2012, assigned to Takeda Pharmaceutical Co Ltd

[3] Ennis MD, Hoffman RL, Ghazal NB, Olson RM, Knauer CS, Chio CL, et al. (July 2003). "2,3,4,5-tetrahydro- and 2,3,4,5,11,11a-hexahydro-1H-[1,4]diazepino[1,7-a]indoles: new templates for 5-HT(2C) agonists". Bioorganic & Medicinal Chemistry Letters. 13 (14): 2369–72. doi:10.1016/S0960-894X(03)00403-7. PMID 12824036.

[1]

[2]

[3]

v t e Tryptamines
Tryptamines	1-Methyl-DMT (1,N,N-TMT, 1-TMT) 1-Methyl-T 2-HO-NMT 2-Methyl-DET 2-Methyl-DiPT 2-Methyl-iPALT (ASR-3002) 2,N,N-TMT (2-methyl-DMT) 3-IAAR 4-Fluoro-DMT 4-Fluoro-T 5-Bromo-DMT 5-Bromo-T 5-Chloro-DMT 5-Chloro-T 5-CT 5-Ethyl-DMT 5-Fluoro-DET 5-Fluoro-DMT 5-Fluoro-EPT 5-Fluoro-T 5-Me-MiPT 5-MeS-DMT 5-Methyl-DMT 5-Methyl-T 6-Fluoro-DET 6-Fluoro-DMT 6-Fluoro-T 6-HO-DET 6-HO-DMT 6-HO-T (6-HT) 6-MeO-DMT 6-MeO-T 6-Methyl-T 6,7-DHT 7-Chloro-T 7-HO-T (7-HT) 7-MeO-DMT 7-MeO-T 7-Methyl-DMT 7-Methyl-T Acetryptine (5-AT) Almotriptan Benzotript (4-CB-Trp) BGE Bretisilocin (5-fluoro-MET; GM-2505) Convolutindole A (2,4,6-TBr,1,7-DiMeO-DMT) DALT DAT DBT Desformylflustrabromine DET (T-9) DHT DiPT DMT DPT E-6801 E-6837 EB-003 EiPT EPT FGIN-127 FGIN-143 Idalopirdine iPALT (ALiPT; ASR-3003) Lespedamine (1-MeO-DMT) L-694247 MBT MET MiPT MPT MsBT N-Benzyltryptamine (T-NB, NB-T) N-DEAOP-NET N-DEAOP-NMT NAT NBoc-DMT NET/NETP NHT NiPT NMT NsBT NtBT PALT (ASR-3004) PiPT Rizatriptan ST-1936 (2-Me-5-Cl-DMT) Sumatriptan TCS-1205 Tryptamine (T; indolylethylamine) Tryptophan (Trp) WAY-181187 Yuremamine Z2876442907 Zolmitriptan
4-Hydroxytryptamines and esters/ethers	1-Methylpsilocin (CMY-16) 4-AcO-DALT 4-AcO-DET (ethacetin, ethylacybin) 4-AcO-DiPT (ipracetin) 4-AcO-DMT (psilacetin; O-acetylpsilocin) 4-AcO-DPT (depracetin) 4-AcO-EPT 4-AcO-MALT 4-AcO-MET (metacetin) 4-AcO-MiPT (mipracetin) 4-AcO-NMT 4-AcO-TMT 4-HO-5-MeO-T 4-HO-DALT (daltocin) 4-HO-DBT 4-HO-DET (ethocin; CZ-74) 4-HO-DiBT 4-HO-DiPT (iprocin) 4-HO-DPT (deprocin) 4-HO-DsBT 4-HO-EiBT (eibucin) 4-HO-EiPT 4-HO-EPT (eprocin) 4-HO-MALT (maltocin) 4-HO-MET (metocin) 4-HO-McPT 4-HO-McPeT 4-HO-MiPT (miprocin) 4-HO-MPT (meprocin) 4-HO-MsBT 4-HO-NALT 4-HO-NBnT 4-HO-NcHT 4-HO-NET 4-HO-NiPT 4-HO-NBT (4-HO-NnBT) 4-HO-NPT 4-HO-NtBT 4-HO-PiPT (piprocin) 4-HO-TMT 4-HT (dinorpsilocin) 4-MeO-DET 4-MeO-DiPT 4-MeO-DMT 4-MeO-MiPT 4-MeO-T 4-PrO-DiPT 4-PrO-DMT 4,5-DHT 4,5-MDO-DMT 4,5-MDO-DiPT Aeruginascin (4-PO-TMT) Baeocystin (4-PO-NMT) EB-002 (EB-373) Ethocybin (4-PO-DET; CEY-19) Luvesilocin (4-GO-DiPT; RE-104; FT-104) MSP-1014 Norbaeocystin (4-PO-T) Norpsilocin (4-HO-NMT) O-4310 (1-iPrO-6-F-psilocin) Psilocin (4-HO-DMT; CX-59) Psilocybin (4-PO-DMT; CY-39) Psilomethoxin (4-HO-5-MeO-DMT) Psilomethoxybin (4-PO-5-MeO-DMT) RE-109 (4-GO-DMT)
5-Hydroxy- and 5-methoxytryptamines	2-Methyl-5-HT 2-Methyl-5-MeO-DALT 4-HO-5-MeO-T 4-F-5-MeO-DMT 4,5-DHP-DMT 4,5-DHT 4,5-MDO-DMT 4,5-MDO-DiPT 5-BT 5-Ethoxy-DMT 5-HO-DET 5-HO-DiPT 5-HO-NiPT 5-HO-DPT 5-HTP (oxitriptan) 5-MeO-2-TMT 5-MeO-34MPEMT 5-MeO-7,N,N-TMT 5-MeO-DALT 5-MeO-DBT 5-MeO-DET 5-MeO-DiPT 5-MeO-DMT (N,N,O-TMS; O-methylbufotenine) 5-MeO-DPT 5-MeO-EiPT 5-MeO-EPT 5-MeO-MALT 5-MeO-MET 5-MeO-MiPT 5-MeO-NET 5-MeO-NiPT 5-MeO-NMT (O,N-DMS) 5-MeO-PiPT 5-MeO-NBpBrT 5-MeO-T (5-MT; mexamine; O-methylserotonin) 5-MeO-T-NBOMe 5-MT-NB3OMe 5-NOT 5,6-DHT 5,6-MDO-DiPT 5,6-MDO-DMT 5,6-MDO-MiPT 5,6-MeO-MiPT 5,7-DHT Arachidonoyl serotonin ASR-3001 (5-MeO-iPALT) BAB Benanserin (BAS; SQ-4788) BGC20-761 Bufotenidine (5-HTQ; N,N,N-TMS) Bufotenin (5-HO-DMT; N,N-DMS; mappine) Bufoviridine (5-SO-DMT) CP-132,484 Cqd 280 Cqd 285 Cqdd 280 Donitriptan EMDT (2-Et-5-MeO-DMT) HIOC Indorenate (TR-3369) Isamide (N-CA-5-MT) L-741604 MS-245 N-DEAOP-5-MeO-NET N-DEAOP-5-MeO-NMT N-Feruloylserotonin (moschamine) Norbufotenin (5-HO-NMT; NMS) O-Acetylbufotenine (5-AcO-DMT) O-Pivalylbufotenine (5-t-BuCO-DMT) Psilomethoxin (4-HO-5-MeO-DMT) Psilomethoxybin (4-PO-5-MeO-DMT) Serotonin (5-HT)
N-Acetyltryptamines	2-Iodomelatonin 2-Phenylmelatonin 5-Methoxyluzindole 6-Chloromelatonin 6-Fluoromelatonin 6-Hydroxymelatonin 6-Methoxymelatonin 6,7-Dichloro-2-methylmelatonin α-Methylmelatonin Luzindole Melatonin (N-Ac-O-Me-serotonin; N-Ac-5-MeO-T) Normelatonin (N-acetylserotonin; NAS) N-Acetyltryptamine N-Butanoylmelatonin N-Propionylmelatonin Piromelatine TIK-301 (LY-156735)
α-Alkyltryptamines	1-Methyl-AMT 2,α-DMT (2-Me-AMT) 4-HO-αET 4-HO-αMT (MP-14) 4-Methyl-αET 4-Methyl-αMT (MP-809) 5-Chloro-αET (PAL-526) 5-Chloro-αMT (PAL-542) 5-Fluoro-αET (PAL-545) 5-Fluoro-αMT (PAL-212; PAL-544) 5-Methyl-αET 6-Fluoro-αMT 7-Chloro-αMT 7-Me-αET α-Methyltryptophan (αMTP) α,N-DMT (N-Me-αMT; SKF-7024, Ro 3-1715) α,N,N-TMT (α-Me-DMT; Alpha-N) αET (etryptamine; Monase) αMT (Indopan; IT-290; 3-API; 3-IT) IPAP (α,N-DPT) N-Hydroxy-AMT Soclenicant (BNC-210; Ile–Trp) 5-Hydroxy- and 5-alkoxy-α-alkyltryptamines: 1-Pr-5-MeO-AMT 5-Allyloxy-AMT 5-Ethoxy-αMT 5-iPrO-αMT 5-MeO-αET 5-MeO-αMT (α,O-DMS; Alpha-O) α-Methyl-5-HTP α-Methylmelatonin α-Methylserotonin (5-HO-αMT; α-Me-5-HT) α,N,O-TMS (5-MeO-α,N-DMT) α,N,N,O-TeMS (5-MeO-α,N,N-TMT) AL-37350A (4,5-DHP-αMT) BW-723C86 β-Keto-α-alkyltryptamines: BK-5Br-NM-AMT BK-5Cl-NM-AMT BK-5F-NM-AMT BK-NM-AMT
Cyclized tryptamines	5-MeO-IsoqT Barettin Cyclic 3-OHM Ergolines and lysergamides (e.g., LSD) Harmala alkaloids and β-carbolines (e.g., 5-methoxyharmalan, 6-MeO-THH, 6-methoxyharmalan, 9-Me-BC, β-carboline (norharman), fenharmane, harmaline, harmalol, harmane, harmine, LY-266,097, pinoline, tetrahydroharmine, tryptoline) Iboga alkaloids (e.g., ibogaine, ibogamine, noribogaine, tabernanthine) Ibogalogs (e.g., catharanthalog, fluorogainalog, ibogainalog, ibogaminalog (DM-506), LS-22925, noribogainalog, noribogaminalog, PHA-57378, PNU-22394, tabernanthalog) Imidazolylindoles (e.g., AGH-107, AGH-192, AH-494) Metralindole Morpholinylethylindoles (e.g., mor-T, 5-MeO-mor-T) Partial ergolines and lysergamides (e.g., NDTDI, RU-27849, RU-28251, RU-28306, FHATHBIN, LY-178210, Bay R 1531 (LY-197206), LY-293284, 10,11-seco-LSD, 10,11-secoergoline (α,N-Pip-T), CT-5252) Pertines (e.g., alpertine, milipertine, oxypertine, solypertine) Piperidinylethylindoles (e.g., pip-T, 5-MeO-pip-T, indolylethylfentanyl) Pyrrolidinylethylindoles (e.g., pyr-T, 4-HO-pyr-T, 5-MeO-pyr-T, 4-F-5-MeO-pyr-T) Pyrrolidinylmethylindoles (e.g., MPMI, 4-HO-MPMI (lucigenol), 5F-MPMI, 5-MeO-MPMI, CP-122288, CP-135807, eletriptan) Tetrahydrocarbazolamines (e.g., ciclindole, flucindole, frovatriptan, LY-344864, ramatroban) Tetrahydropyridinylindoles (e.g., RS134-49, RU-28253, NEtPhOH-THPI) Tetrahydropyrroloquinolines (e.g., bufothionine, O-methylnordehydrobufotenine, dehydrobufotenine) Yohimbans (e.g., yohimbine, rauwolscine, spegatrine, corynanthine, ajmalicine, reserpine, deserpidine, rescinnamine)
Isotryptamines	5-MeO-isoDMT 6-MeO-isoDMT isoAMT (1-API; 1-IT; α-Me-isoT) isoDMT Isotryptamine (isoT) Ro60-0175 VER-3323 Zalsupindole (DLX-001, AAZ-A-154) Cyclized isotryptamines: JRT PNU-181731
Related compounds	2-Azapsilocin 4-Aza-5-MeO-DPT 5-Aza-4-MeO-DiPT 5-HIAA 5-HIAL 5-HITCA 5-MIAL 7-Aza-5-MeO-DiPT α-Carboline γ-Carbolines (pyridoindoles) (e.g., γ-carboline, alosetron, gevotroline, latrepirdine, lurosetron, mebhydrolin, tiflucarbine) Amedalin Benzindopyrine Benzofurans (e.g., 3-APB, 5-MeO-DiBF, BPAP, 3-F-BPAP, dimemebfe, mebfap, oxa-noribogaine) Benzothiophenes (e.g., 3-APBT) Carmoxirole CT-4436 Daledalin Gramine Histamine Homotryptamines (e.g., HT, DMHT) I-32 IAL IN-399 Indazolethylamines (e.g., AL-34662, AL-38022A, O-methyl-AL-34662, VU6067416, YM-348) Indenylethylamines (e.g., C-DMT) Indolizinylethylamines (e.g., TACT908 (2ZEDMA), 1ZP2MA, 1Z2MAP1O) Indolylaminopropanes (e.g., 1-API, 2-API, 4-API, 5-API (5-IT; PAL-571), 6-API (6-IT), 7-API) Iprindole Masupirdine Medmain Molindone Non-tryptamine triptans (e.g., avitriptan, LY-334370, naratriptan) Ondansetron Oxazinopyridoindoles (e.g., IHCH-8134) Phenethylamines (e.g., phenethylamine, amphetamine) Piperidinylbenzimidazolines (e.g., benperidol, timiperone) Piperazinylbenzisothiazoles (e.g., lurasidone, perospirone, tiospirone, ziprasidone) Piperidinylbenzisoxazoles (e.g., iloperidone, milsaperidone, ocaperidone, paliperidone, risperidone) Piperidinylindoles (e.g., BRL-54443, LY-334370, naratriptan, sertindole, SN-22) Pirlindole Pyridinylbenzimidazoles (e.g., droperidol) Pyridinylindoles (e.g., tepirindole) Pyridopyrroloquinoxalines (e.g., IHCH-7113, IHCH-7079, IHCH-7086, lumateperone, deulumateperone, ITI-1549) Pyrrolylethylamines (e.g., 2-pyrrolylethylamine (NEA), 3-pyrrolylethylamine (3-NEA), 3-pyrrolylpropylamine) Pyrrolopyridinylethylamines (e.g., WAY-208466) Quinolinylethylamines (e.g., mefloquine) Ro60-0213 Selisistat Tetrahydropyridinylindoles (e.g., EMD-386088, LY-367265, RU-24,969) Tetrahydropyridinylpyrrolopyridines (e.g., (R)-69 (3IQ), (R)-70, CP-94253) Tetrindole Tipindole Zilpaterol (RU-42173)
See also: Phenethylamines Ergolines and lysergamides Psychedelics

Identifiers


IUPAC name 2,3,4,5-tetrahydro-1H-[1,4]diazepino[1,7-a]indole
CAS Number	364344-56-9 ^Y
PubChem CID	9794092
ChemSpider	7969859
UNII	UVL6VJD7YC
CompTox Dashboard (EPA)	DTXSID201045564
Chemical and physical data
Formula	C₁₂H₁₄N₂
Molar mass	186.258 g·mol⁻¹
3D model (JSmol)	Interactive image
SMILES C12=CC=CC=C1N3C(CCNCC3)=C2
InChI InChI=1S/C12H14N2/c1-2-4-12-10(3-1)9-11-5-6-13-7-8-14(11)12/h1-4,9,13H,5-8H2 Key:XORPZYQOYUSNCQ-UHFFFAOYSA-N

PNU-181731

See also

References