Phenethylamine
Chemical name	2-Phenyl-ethylamine or 2-phenylethanamine
Chemical formula	C8H11N
Molecular mass	121.18 g/mol
Density	0.965 g/ml
Melting point	-60 °C
Boiling point	200 °C
CAS number	64-04-0
SMILES	NCCC1=CC=CC=C1

Phenethylamine is an alkaloid and monoamine. In the human brain, it is discussed as a putative neuromodulator or neurotransmitter. In nature phenethylamine is synthesized from the amino acid phenylalanine by enzymatic decarboxylation. It is also found in many foods, especially after microbial fermentation, e.g. in chocolate. Phenethylamine is a colorless liquid that forms a solid carbonate salt with carbon dioxide (CO₂) upon exposure to air. Phenethylamine from food (e.g. chocolate) has been discussed to have psychoactive effects. However, it is quickly metabolized by the enzyme MAO-B so that significant concentrations do not reach the brain.

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

The phenethylamine structure can also be found as part of more complex ring systems like in the ergoline system of LSD or the morphinan system of morphine.

Contents

1 Substituted phenethylamines 2 Pharmacology 3 Substitution table 4 See also 5 External links 6 Categorization

Substituted phenethylamines

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

• Amphetamines are 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.

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 drugs amphetamine (speed, benzedrine) and methylphenidate.
• Hallucinogens like the plant alkaloid mescaline and the synthetic drug 2C-B.
• Empathogens like MDMA (ecstasy) and MDA.
• Anorectics like phentermine, fenfluramine, and amphetamine.
• Bronchodilators like salbutamol and ephedrine.
• Antidepressants like 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-methyl-phenethylamine
Norepinephrine (Noradrenaline)		OH		OH	OH			β,3,4-trihydroxyphenethylamine
Salbutamol		OH			OH	CH2CH2OH	C(CH3)3	4-(2-(tert-Butylamino)-1-hydroxyethyl)-2-(hydroxymethyl)phenol
Amphetamine	CH3							α-methyl-phenethylamine
Methamphetamine	CH3						CH3	N-methyl-amphetamine
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-tert-butyl-β-keto-amphetamine
Fenfluramine	CH3			CF3			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
DOM	CH3		OCH3		CH3	OCH3		2,5-dimethoxy-4-methyl-amphetamine
DOB	CH3		OCH3		Br	OCH3		2,5-dimethoxy-4-bromo-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-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		SCH2CHCH2CH2	OCH3		2,5-dimethoxy-4-cyclopropyl methylthio-phenethylamine
2C-T-9			OCH3		S-(CH3)3C	OCH3		2,5-dimethoxy-4-(t)-Butyl thio-phenethylamine
2C-T-21			OCH3		SCH2CH2F	OCH3		2,5-dimethoxy-4-(2-fluoroethylthio)-phenethylamine

See also

• Catecholamines
• PiHKAL
• Alexander Shulgin

External links

• Book II of PiHKAL online
• Review and summary of PiHKAL, including table of 300+ phenethylamines: ascii postscript
• A Structural Tour of PiHKAL

Categorization