Phenethylamine

Phenethylamine (1-amino-2-phenylethane) is a monoamine compound that is widespread in nature, even found in chocolate, but as well as the human brain where it is discussed as a putative neuromodulator or neurotransmitter. In nature phenethylamine is synthesized from the amino acid phenylalanine by enzymatic decarboxylation, likewise tyramine (4-hydroxy-phenethylamine) is synthesized from tyrosine.

Some consider phenethylamine from food to have psychoactive effects, however, it is quickly metabolized by the enzyme MAO so that significant concentrations do not reach the brain.

Substitutions to the phenethylamine molecule give rise to a group of compounds collectively known as phenethylamines. The term amphetamines is used to refer to the subset of phenethylamines that can be derived from substitution to amphetamine (α-methylphenethylamine), while those that derive from tyrosine are called catecholamines. Phenethylamines are widespread in nature as hormones, neurotransmitters and alkaloids. Examples of fundamental importance in the human nervous system are dopamine, epinephrine (adrenaline) and norepinephrine (noradrenaline). Plant alkaloids related to phenethylamine include the psychedelic drug mescaline, and the stimulants ephedrine and cathinone. Many synthetic phenethylamines have been investigated for their psychoactive effects, which are generally stimulant, empathogenic and/or psychedelic in nature. The most commonly used synthetic phenethylamines are amphetamine (speed, Benzedrine), methamphetamine (meth, ice) and MDMA (Ecstasy). A phenethylamine backbone can also be identified in the more complex structure of LSD. Some of the more important phenethylamines are tabulated below according to their structure. For simplicity the stereochemistry of these compounds is not covered in the table. Hundreds of other synthetic phenethylamines are known. This is due in large part to the pioneering work of Alexander Shulgin, much of which is described in the book PiHKAL.

Substituted phenethylamines, tabulated by structure

Short Name	α	β	R2	R3	R4	R5	N1	Full Name
tyramine					OH			4-hydroxy-phenethylamine
dopamine				OH	OH			3,4-dihydroxy-phenethylamine
epinephrine		OH		OH	OH		CH3	β,3,4-trihydroxy-N-methyl-phenethylamine
norepinephrine		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	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
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-7			OCH3		SCH2CH2CH3	OCH3		2,5-dimethoxy-4-propylthio-phenethylamine
2C-T-8			OCH3		SCH2CHCH2CH2	OCH3		2,5-dimethoxy-4-cyclopropylmethylthio-phenethylamine
2C-T-21			OCH3		SCH2CH2F	OCH3		2,5-dimethoxy-4-(2-fluoroethylthio)-phenethylamine

See also

• catecholamines
• PiHKAL
• Alexander Shulgin