5-Chlorotryptamine

5-Chlorotryptamine (5-Cl-T; developmental code name PAL-441) is a serotonin receptor modulator and monoamine releasing agent of the tryptamine family.^[1] It is the 5-chloro derivative of tryptamine.^[1]

Other names5-Chloro-T; 5-Cl-T; 5-ClT; PAL-441; PAL441

Drug classSerotonin receptor modulator; Serotonin 5-HT_2A receptor agonist; Serotonin releasing agent

ATC code

• None

CAS Number

• 3764-94-1

Quick facts Clinical data, Other names ...

5-Chlorotryptamine

Clinical data
Other names	5-Chloro-T; 5-Cl-T; 5-ClT; PAL-441; PAL441
Drug class	Serotonin receptor modulator; Serotonin 5-HT2A receptor agonist; Serotonin releasing agent
ATC code	None
Identifiers
IUPAC name 2-(5-chloro-1H-indol-3-yl)ethanamine
CAS Number	3764-94-1
PubChem CID	77379
ChemSpider	69793
UNII	9V4S232P62
ChEMBL	ChEMBL1288716
CompTox Dashboard (EPA)	DTXSID50191073
ECHA InfoCard	100.021.077
Chemical and physical data
Formula	C10H11ClN2
Molar mass	194.66 g·mol−1
3D model (JSmol)	Interactive image
SMILES C1=CC2=C(C=C1Cl)C(=CN2)CCN
InChI InChI=1S/C10H11ClN2/c11-8-1-2-10-9(5-8)7(3-4-12)6-13-10/h1-2,5-6,13H,3-4,12H2 Key:FVQKQPVVCKOWLM-UHFFFAOYSA-N

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The drug shows affinity for the serotonin 5-HT_1A, 5-HT_2A, 5-HT₆, and 5-HT₇ receptors (K_i = 5.5–16 nM, 317–889 nM, 38 nM, and 16 nM, respectively).^[2][3][4] It acts as a potent agonist of the serotonin 5-HT_1A receptor (EC₅₀Tooltip half-maximal effective concentration = 3,846 nM) and of the 5-HT_2A receptor (EC₅₀ = 4.11–145 nM; E_maxTooltip maximal efficacy = 109%).^[1][3][4] In addition, 5-chlorotryptamine is a serotonin releasing agent (SRA), with EC₅₀ values for induction of monoamine release of 19.1 nM for serotonin, 476 nM for dopamine, and >10,000 nM for norepinephrine in rat brain synaptosomes.^[1] Similarly to tryptamine and other simple amine-unsubstituted tryptamines, 5-chlorotryptamine was ineffective in producing the head-twitch response, a behavioral proxy of psychedelic effects, in rodents.^[3][4]

Tryptamines without substitutions at the amine or alpha carbon, such as tryptamine, serotonin (5-hydroxytryptamine; 5-HT), and 5-methoxytryptamine (5-MeO-T), are known to be very rapidly metabolized and thereby inactivated by monoamine oxidase A (MAO-A) in vivo and to have very short elimination half-lives.^{[5][6][7][8][9][10][11]} However, given intravenously at sufficiently high doses, tryptamine is still known to be able to produce weak and short-lived psychoactive effects in humans.^{[12][6][1][11]}

The chemical synthesis of 5-chlorotryptamine has been described.^[1]

5-Chlorotryptamine was first described in the scientific literature by 1959.^[13][14]