Phenethylamines

Biological: Behavioural genetics · Evolutionary psychology · Neuroanatomy · Neurochemistry · Neuroendocrinology · Neuroscience · Psychoneuroimmunology · Physiological Psychology · Psychopharmacology (Index, Outline)

Phenethylamine ^[1]

Chemical name	2-Phenylethylamine
Other names	Phenethylamine β-Phenylethylamine 2-Phenyl-1-aminoethane β-Aminoethylamine 2-Phenylethanamine
Chemical formula	C₈H₁₁N
Molecular mass	121.18 g/mol
CAS number	[64-04-0]
Density	0.964 g/cm³
Melting point	-60 °C
Boiling point	194.5-195 °C
SMILES	c1ccccc1CCN
NFPA 704	2 2 2
Disclaimer and references

Phenethylamine, or β-Phenylethylamine, is an alkaloid and monoamine. In the human brain, it 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. The phenethylamine structure can also be found as part of more complex ring systems such as the ergoline system of LSD or the morphinan system of morphine.

Chemistry

Phenethylamine 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.

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 was 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”.^[2]

Substituted phenethylamines

Phenethylamine rests — General structure of phenethylamines and amphetamines (see the table below).

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.
2C's are phenethylamines with methoxy groups attached to the 2 and 5 carbons and no alpha-methyl group.

Pharmacology

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

Stimulants like the plant alkaloids ephedrine and cathinone and the synthetic drug dextroamphetamine and methylphenidate.
Hallucinogens like the plant alkaloid mescaline and the synthetic drug 2C-B.
Empathogen-entactogens like MDMA (ecstasy) and MDA.
Anorectics like phentermine, fenfluramine, and amphetamine.
Bronchodilators like salbutamol and ephedrine.
Antidepressants like venlafaxine, bupropion and the monoamine oxidase inhibitors phenelzine and tranylcypromine.

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	R_α	R_β	R₂	R₃	R₄	R₅	R_N	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-methyl-phenethylamine
Norepinephrine (Noradrenaline)		OH		OH	OH			β,3,4-trihydroxyphenethylamine
Salbutamol		OH			OH	CH₂OH	C(CH₃)₃	β,4-dihydroxy-3-hydroxymethyl-N-(t)-butyl-phenethylamine
Beta-Methyl-phenethylamine		CH₃						β-methyl-phenethylamine
Amphetamine	CH₃							α-methyl-phenethylamine
Methamphetamine	CH₃						CH₃	N-methyl-amphetamine
Methylphenidate								N,α-butylene-β-methoxy carbonyl-phenethylamine
Ephedrine, pseudoephedrine	CH₃	OH					CH₃	N-methyl-β-hydroxy-amphetamine
Cathine	CH₃	OH						β-hydroxy-amphetamine
Cathinone	CH₃	=O						β-keto-amphetamine
Methcathinone	CH₃	=O					CH₃	N-methyl-β-keto-amphetamine
Bupropion	CH₃	=O		Cl			C(CH₃)₃	3-chloro-N-(t)-butyl-β-keto-amphetamine
Fenfluramine	CH₃			C F₃			CH₂CH₃	3-trifluoromethyl-N-ethyl-amphetamine
Phentermine	CH₃,CH₃							α,α-dimethyl-phenethylamine
Mescaline				OCH₃	OCH₃	OCH₃		3,4,5-trimethoxy-phenethylamine
MDA	CH₃			-O-CH₂-O-				3,4-methylenedioxy-amphetamine
MDMA	CH₃			-O-CH₂-O-			CH₃	3,4-methylenedioxy-N-methyl-amphetamine
MDMC	CH₃	=O		-O-CH₂-O-			CH₃	3,4-methylenedioxy-N-methyl-β-keto-amphetamine
DOM	CH₃		OCH₃		CH₃	OCH₃		2,5-dimethoxy-4-methyl-amphetamine
DOB	CH₃		OCH₃		Br	OCH₃		2,5-dimethoxy-4-bromo-amphetamine
DON	CH₃		OCH₃		NO₂	OCH₃		2,5-dimethoxy-4-nitro-amphetamine
2C-B			OCH₃		Br	OCH₃		2,5-dimethoxy-4-bromo-phenethylamine
2C-C			OCH₃		Cl	OCH₃		2,5-dimethoxy-4-chloro-phenethylamine
DOI	CH₃		OCH₃		I	OCH₃		2,5-dimethoxy-4-iodo-amphetamine
2C-I			OCH₃		I	OCH₃		2,5-dimethoxy-4-iodo-phenethylamine
2C-D			OCH₃		CH₃	OCH₃		2,5-dimethoxy-4-methyl-phenethylamine
2C-E			OCH₃		CH₂CH₃	OCH₃		2,5-dimethoxy-4-ethyl-phenethylamine
2C-F			OCH₃		F	OCH₃		2,5-dimethoxy-4-Fluoro-phenethylamine
2C-N			OCH₃		NO₂	OCH₃		2,5-dimethoxy-4-Nitro-phenethylamine
2C-T-2			OCH₃		SCH₂CH₃	OCH₃		2,5-dimethoxy-4-ethylthio-phenethylamine
2C-T-4			OCH₃		SCHCH₃CH₃	OCH₃		2,5-dimethoxy-4-(i)-propylthio-phenethylamine
2C-T-7			OCH₃		SCH₂CH₂CH₃	OCH₃		2,5-dimethoxy-4-propylthio-phenethylamine
2C-T-8			OCH₃		S CH₂CHCH₂CH₂	OCH₃		2,5-dimethoxy-4-cyclopropylmethylthio-phenethylamine
2C-T-9			OCH₃		S-(CH₃)₃C	OCH₃		2,5-dimethoxy-4-(t)-Butylthio-phenethylamine
2C-T-21			OCH₃		SCH₂CH₂F	OCH₃		2,5-dimethoxy-4-(2-fluoroethylthio)-phenethylamine

Graphical overview

References

↑ ^1.0 ^1.1 Merck Index, 12th Edition, 7371.
↑ Liebowitz, Michael, R. (1983). The Chemistry of Love. Boston: Little, Brown, & Co.

External links

MSDS for phenethylamine
Book II of PiHKAL online
Review and summary of PiHKAL, including table of 300+ phenethylamines: ascii postscript
A Structural Tour of PiHKAL
Link page to external chemical sources.

This box: view • talk • edit

Phenethylamines

{2C-B} {2C-C} {2C-D} {2C-E} {2C-I} {2C-N} {2C-T-2} {2C-T-21} {2C-T-4} {2C-T-7} {2C-T-8} {3C-E} {4-FMP} {Bupropion} {Cathine} {Cathinone} {DESOXY} {Dextroamphetamine} {Methamphetamine} {Diethylcathinone} {Dimethylcathinone} {DOC} {DOB} {DOI} {DOM} {bk-MBDB} {Dopamine} {Br-DFLY} {Ephedrine} {Epinephrine} {Escaline} {Fenfluramine} {Levalbuterol} {Levmetamfetamine} {MBDB} {MDA} {MDMA} {bk-MDMA/MDMC/MDMCat/Methylone} {MDEA} (MDPV) {Mescaline} {Methcathinone} {Methylphenidate} {Norepinephrine} {Phentermine} {Salbutamol} {Tyramine} {Venlafaxine}

.

This page uses Creative Commons Licensed content from Wikipedia (view authors).

[Merck-1] 1.0 ^1.1 Merck Index, 12th Edition, 7371.

[2] Liebowitz, Michael, R. (1983). The Chemistry of Love. Boston: Little, Brown, & Co.

[1]

[2]