Pyr-T

Pyr-T, also known as N,N-tetramethylenetryptamine or as 3-(2-pyrrolidinoethyl)indole, is a lesser-known serotonin receptor modulator of the tryptamine family.^[1][2] It is the cyclized derivative of diethyltryptamine (DET) in which the N,N-diethyl groups have been fused into a pyrrolidine ring.^[2]

Pyr-T

Clinical data
Other names	N,N-Tetramethylenetryptamine; N,N-Pyrrolidinyltryptamine; Pyrrolidinyltryptamine; Pyr-Tryptamine; 3-(2-Pyrrolidinoethyl)indole
Routes of administration	Oral, inhalation[1]
Drug class	Serotonin receptor modulator
ATC code	None
Identifiers
IUPAC name 3-[2-(pyrrolidin-1-yl)ethyl]-1H-indole
CAS Number	14008-96-9 Y
PubChem CID	26393
ChemSpider	24588 Y
UNII	VZ689W7HWX
CompTox Dashboard (EPA)	DTXSID00161226
Chemical and physical data
Formula	C14H18N2
Molar mass	214.312 g·mol−1
3D model (JSmol)	Interactive image
Melting point	193 to 194 °C (379 to 381 °F) (hydrochloride salt)
Boiling point	170 to 180 °C (338 to 356 °F) (freebase at 0.05 mm/Hg)
SMILES c2c(c1ccccc1[nH]2)CCN3CCCC3
InChI InChI=1S/C14H18N2/c1-2-6-14-13(5-1)12(11-15-14)7-10-16-8-3-4-9-16/h1-2,5-6,11,15H,3-4,7-10H2 Y Key:CVTZCBLFHNGYDQ-UHFFFAOYSA-N Y
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Use and effects

In his 1997 book TiHKAL (Tryptamines I Have Known and Loved), Alexander Shulgin reported neither the dose range nor the duration of the drug.^[1][3] However, individual experiments employed 25 to 50 mg orally and 70 mg smoked.^[1] Pyr-T produced effects including malaise, feeling sick, unpleasantness, salivation, muscle and joint pains, dizziness, feeling high, and uncomfortableness.^[1] Hallucinogenic effects, for instance visuals, were either absent or minor.^[1]

Pharmacology

Pyr-T has been found to show affinity for serotonin receptors, including the serotonin 5-HT_1A, 5-HT_2A and 5-HT_2C receptors.^[4][5] Its affinities (IC₅₀Tooltip half-maximal inhibitory concentration) for these receptors were 30 nM for the serotonin 5-HT_1A receptor, 110 nM for the 5-HT_2A receptor, and 750 nM for the serotonin 5-HT_2B receptor.^[4][5] The affinities of pyr-T for the serotonin 5-HT_2A and 5-HT_2B receptors were similar to but slightly lower than those of dimethyltryptamine (DMT), whereas its affinity for the serotonin 5-HT_1A receptor was 5.7-fold higher than that of DMT and was intermediate between those of DMT and 5-MeO-DMT.^[4][5] The serotonin 5-HT_1A to 5-HT_2A receptor affinity ratios in the study were about 0.27 for pyr-T, 0.5 for 5-MeO-DMT, 1.4 for bufotenin, 2.3 for DMT, and 32 for psilocin.^[5]

Pyr-T has been found to produce behavioral changes in animal tests.^[2][6][7] It was described as being as potent as diethyltryptamine (DET) in rodents, cats, and primates, but that it also had a poor margin of activity relative to toxicity and was unlikely to be tested in humans.^[2] It has been found to produce hypolocomotion in rodents.^[7] Conversely, pyr-T (3 mg/kg) failed to acutely produce the head-twitch response, a behavioral proxy of psychedelic effects, in rodents.^[7]

Chemistry

See also: Substituted tryptamine

Pyr-T is a substituted tryptamine in which the amine moiety has been replaced with a pyrrolidine ring. It can be thought of as a cyclized derivative of diethyltryptamine (DET) in which the N,N-ethyl groups have been connected to form the pyrrolidine ring present in pyr-T.

Derivatives of pyr-T include 4-HO-pyr-T, 5-MeO-pyr-T, and 4-F-5-MeO-pyr-T. Analogues of pyr-T include pip-tryptamine, 10,11-secoergoline (α,N-Pip-T), MPMI, and SN-22, among others.

History

Pyr-T was first characterized by Mitzal by 1962.^[8] Animal toxicity testing was later performed by Hunt and Brimblecombe by 1967.^[2][6] The effects of pyr-T in humans were described by Alexander Shulgin in his book TiHKAL in 1997.^[1]