PHENETHYLAMINE

'' ''Merck Index'', 12th Edition, '7371'.
Chemical structure of Phenethylamine
Chemical name
Other names	Phenethylamine β-Phenylethylamine 2-Phenyl-1-aminoethane β-Aminoethylamine 2-Phenylethanamine
Chemical formula
Molecular mass	g/mol
CAS number	[]
Density	g/cm3
Melting point	°C
Boiling point	°C
SMILES
NFPA 704

'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.

Contents

Chemistry

Chocolate theory of love

Substituted phenethylamines

Pharmacology

Substitution table

Graphical overview

See also

References

External links

Chemistry

Phenethylamine is an aromatic amine which is a colorless liquid at room temperature. It is soluble in water, ethanol, and ether. 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”.^[1] However as noted earlier, phenethylamine is rapidly metabolized by the enzyme MAO-B, preventing significant concentrations from reaching the brain, thus no psychoactive effect is achieved.

Substituted phenethylamines

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	''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
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
Ephedrine, pseudoephedrine	CH3	OH					CH3	''N''-methyl-β-hydroxyamphetamine
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

★ Catecholamines

★ PiHKAL

★ Alexander Shulgin

★ Venom (comics) An alien in the fictional Spider Man comic series relies on this chemical to sustain itself.

★ Phenethyl alcohol

★ 2C's

References

1. 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