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IUPAC name 2-Phenylethylamine
Other names Phenethylamine
CAS number 64-04-0
SMILES c1ccccc1CCN
Molecular formula C8H11N
Molar mass 121.18 g/mol
Density 0.964 g/cm3
Melting point

-60 °C

Boiling point

194.5-195 °C

NFPA 704
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Phenethylamine, or β-Phenylethylamine (2-Phenylethylamine), is an alkaloid and monoamine. Phenethylamine has also structural isomer α- or 1-phenylethylamine, which has two stereoisomers: (R)-(+)-1-phenylethylamine and (S)-(-)-1-phenylethylamine. In the human brain, 2-phenethylamine is believed to function as a neuromodulator or neurotransmitter (trace amine). Phenethylamine is a natural compound biosynthesized from the amino acid phenylalanine by enzymatic decarboxylation. It is also found in many foods such as chocolate, especially after microbial fermentation. It has been suggested that phenethylamine from food may have psychoactive effects in sufficient quantities. However, it is quickly metabolized by the enzyme MAO-B, preventing significant concentrations from reaching the brain.

Substituted phenethylamines are a broad and diverse class of compounds that include neurotransmitters, hormones, stimulants, hallucinogens, entactogens, anorectics, bronchodilators, and antidepressants.



Phenethylamine (PEA) is an aromatic amine, which is a colorless liquid at room temperature. It is soluble in water, ethanol, and ether.[1] Similar to other low-molecular-weight amines, it has a fishy odor. Upon exposure to air, it forms a solid carbonate salt with carbon dioxide. Phenethylamine is strongly basic and forms a stable crystalline hydrochloride salt with a melting point of 217 °C. Phenethylamine is also a skin irritant and possible sensitizer.


Infusion of PEA increased extracellular levels of dopamine[2] while at the same time inhibiting DA neuron firings.[3][4] It also modulates noradrenergic transmission.[5] It has GABAergic antagonism.[6]

Low levels are found in ADHD[7] and often in depression, while levels are elevated in schizophrenia.[8] This is associated with low dopamine in ADHD and depression and high dopamine in schizophrenia.

Chocolate theory of love

In the early 1980s, chemistry of love researcher Michael Libowitz, author of the popular 1983 book The Chemistry of Love, remarked to reporters that "chocolate is loaded with PEA." This became the focus for an article in The New York Times, which was then taken up by the wire services, then by magazine free-lancers, and evolved into the now-eponymous "chocolate theory of love."[9] However, as noted earlier, phenethylamine is rapidly metabolized by the enzyme MAO-B, preventing significant concentrations from reaching the brain, thus contributing no perceptible psychoactive effect.

Substituted phenethylamines


Substituted phenethylamines carry additional chemical modifications at the phenyl ring, the sidechain, or the amino group:

  • Substituted Amphetamines are homologues of phenethylamines carrying an alpha-methyl (α-CH3) group at the sidechain carbon atom next to the amino group.
  • Catecholamines are phenethylamines carrying two hydroxy groups in positions 3 and 4 of the phenyl ring. Examples are the hormones and neurotransmitters dopamine, epinephrine (adrenaline), and norepinephrine (noradrenaline).
  • The aromatic amino acids phenylalanine and tyrosine are phenethylamines carrying a carboxyl group (COOH) in alpha position.
  • 2Cs are phenethylamines with methoxy groups attached to the 2 and 5 carbons and no alpha-methyl group.


Many substituted phenethylamines are pharmacologically active drugs due to their similarity to the monoamine neurotransmitters:

Substitution table

Some of the more important phenethylamines are tabulated below. For simplicity, the stereochemistry of the sidechain is not covered in the table. Hundreds of other simple synthetic phenethylamines are known. This is due in part to the pioneering work of Alexander Shulgin, much of which is described in the book PiHKAL.

Substituted phenethylamines, tabulated by structure
Short Name Rα Rβ R2 R3 R4 R5 RN Full Name
Tyramine OH 4-hydroxy-phenethylamine
Dopamine OH OH 3,4-dihydroxy-phenethylamine
Epinephrine (Adrenaline) OH OH OH CH3 β,3,4-trihydroxy-N-methylphenethylamine
Norepinephrine (Noradrenaline) OH OH OH β,3,4-trihydroxyphenethylamine
6-Hydroxydopamine OH OH OH 2,4,5-trihydroxyphenethylamine
Salbutamol OH OH CH2OH C(CH3)3 β,4-dihydroxy-3-hydroxymethyl-N-tert-butyl-phenethylamine
Beta-methyl-phenethylamine CH3 β-methylphenethylamine
Amphetamine CH3 α-methylphenethylamine
Methamphetamine CH3 CH3 N-methylamphetamine
Methylphenidate N,α-butylene-β-methoxycarbonylphenethylamine
CH3 OH CH3 N-methyl-β-hydroxyamphetamine
Acetylamphetamine CH3 COCH3 α-methyl-3-acetylphenethylamine
Cathine CH3 OH β-hydroxy-amphetamine
Cathinone CH3 =O β-ketoamphetamine
Methcathinone CH3 =O CH3 N-methyl-β-ketoamphetamine
Bupropion CH3 =O Cl C(CH3)3 3-chloro-N-tert-butyl-β-ketoamphetamine
Fenfluramine CH3 CF3 CH2CH3 3-trifluoromethyl-N-ethyl-amphetamine
Phentermine 2CH3 α,α-dimethylphenethylamine
Mescaline OCH3 OCH3 OCH3 3,4,5-trimethoxyphenethylamine
MDA CH3 -O-CH2-O- 3,4-methylenedioxyamphetamine
MDMA CH3 -O-CH2-O- CH3 3,4-methylenedioxy-N-methylamphetamine
MDMC CH3 =O -O-CH2-O- CH3 3,4-methylenedioxy-N-methyl-β-ketoamphetamine
DOM CH3 OCH3 CH3 OCH3 2,5-dimethoxy-4-methylamphetamine
DOB CH3 OCH3 Br OCH3 2,5-dimethoxy-4-bromoamphetamine
DON CH3 OCH3 NO2 OCH3 2,5-dimethoxy-4-nitroamphetamine
2C-B OCH3 Br OCH3 2,5-dimethoxy-4-bromophenethylamine
2C-C OCH3 Cl OCH3 2,5-dimethoxy-4-chlorophenethylamine
DOI CH3 OCH3 I OCH3 2,5-dimethoxy-4-iodoamphetamine
2C-I OCH3 I OCH3 2,5-dimethoxy-4-iodophenethylamine
2C-D OCH3 CH3 OCH3 2,5-dimethoxy-4-methylphenethylamine
2C-E OCH3 CH2-CH3 OCH3 2,5-dimethoxy-4-ethylphenethylamine
2C-F OCH3 F OCH3 2,5-dimethoxy-4-fluorophenethylamine
2C-N OCH3 NO2 OCH3 2,5-dimethoxy-4-nitrophenethylamine
2C-T-2 OCH3 S-CH2CH3 OCH3 2,5-dimethoxy-4-ethylthio-phenethylamine
2C-T-4 OCH3 S-CH(CH3)2 OCH3 2,5-dimethoxy-4-isopropylthio-phenethylamine
2C-T-7 OCH3 S-CH2CH2CH3 OCH3 2,5-dimethoxy-4-propylthio-phenethylamine
2C-T-8 OCH3 S-CH2-C3H5 OCH3 2,5-dimethoxy-4-cyclopropylmethylthio-phenethylamine
2C-T-9 OCH3 S-C(CH3)3 OCH3 2,5-dimethoxy-4-tert-butylthio-phenethylamine
2C-T-21 OCH3 S-CH2-CH2-F OCH3 2,5-dimethoxy-4-(2-fluoroethylthio)-phenethylamine

Graphical overview

See also


  1. ^ a b Merck Index, 12th Edition, 7371.
  2. ^ Nakamura, Ishii, Nakahara. "Characterization of β-phenylethylamine-induced monoamine release in rat nucleus accumbens : a microdialysis study". European journal of pharmacology.
  3. ^ Kota Ishida, Mikio Murata et al.. "Effects of -Phenylethylamine on Dopaminergic Neurons of the Ventral Tegmental Area in the Rat: A Combined Electrophysiological and Microdialysis Study". Journal of Pharmacology And Experimental Therapeutics Fast Forward.
  4. ^ EM Parker and LX Cubeddu. "Comparative effects of amphetamine, phenylethylamine and related drugs on dopamine efflux, dopamine uptake and mazindol binding".
  5. ^ I. A. Paterson. "The potentiation of cortical neuron responses to noradrenaline by 2-phenylethylamine is independent of endogenous noradrenaline". Neurochemical Resarch.
  6. ^ M Federici et al.. "{{{title}}}".
  7. ^ Baker GB et al.. "Phenylethylaminergic mechanisms in attention-deficit disorder".
  8. ^ SG Potkin et al. "Phenylethylamine in paranoid chronic schizophrenia".
  9. ^ Liebowitz, Michael, R. (1983). The Chemistry of Love. Boston: Little, Brown, & Co.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Phenethylamine". A list of authors is available in Wikipedia.
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