Methiopropamine (MPA) is a

thiophene Thiophene is a heterocyclic compound with the formula C4H4S. Consisting of a planar five-membered ring, it is aromatic as indicated by its extensive substitution reactions. It is a colorless liquid with a benzene-like odor. In most of its reacti ...

ring-based structural analog of

methamphetamine Methamphetamine (contracted from ) is a potent central nervous system (CNS) stimulant that is mainly used as a recreational drug and less commonly as a second-line treatment for attention deficit hyperactivity disorder and obesity. Methamph ...

originally reported in 1942. Chemically it is not a

phenethylamine Phenethylamine (PEA) is an organic compound, natural monoamine alkaloid, and trace amine, which acts as a central nervous system stimulant in humans. In the brain, phenethylamine regulates monoamine neurotransmission by binding to trace amin ...

amphetamine Amphetamine (contracted from alpha- methylphenethylamine) is a strong central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and obesity. It is also commonly used ...

and is not their functional analog either. It originally appeared for public sale in the UK in December 2010 as a "research chemical" or "legal high", recently branded as Blow. It has limited popularity as a recreational stimulant.

Pharmacology

Methiopropamine functions as a selective norepinephrine-dopamine reuptake inhibitor that is approximately 1.85 times more selective for norepinephrine than dopamine. It is approximately one third as potent as dextroamphetamine as a norepinephrine reuptake inhibitor and one fifth as much as a dopamine reuptake inhibitor. It displays negligible activity as a serotonin reuptake inhibitor. Methiopropamine has the potential for significant acute toxicity with cardiovascular, gastrointestinal, and psychotic symptoms.

Metabolism

For ''N''-alkyl amphetamines, deamination and ''N''-

dealkylation Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecting al ...

are the major elimination pathways and renal

excretion Excretion is a process in which metabolic waste is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after lea ...

is a minor one. Methiopropamine is

metabolized Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

into active thiopropamine, 4-hydroxymethiopropamine and

''S''-

oxide An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the E ...

s. These ''N''-

demethylated Demethylation is the chemical process resulting in the removal of a methyl group (CH3) from a molecule. A common way of demethylation is the replacement of a methyl group by a hydrogen atom, resulting in a net loss of one carbon and two hydrogen ato ...

metabolite In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, c ...

s are further deaminated by the

cytochrome P450 Cytochromes P450 (CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are ...

enzyme CYP2C19 in the

liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...

transforming them into inactive 1-(thiophen-2-yl)-2-propan-2-one which can be seen as a

phenylacetone Phenylacetone is an organic compound with the chemical formula C6H5CH2COCH3. It is a colorless oil that is soluble in organic solvents. This substance is used in the manufacture of methamphetamine and amphetamine, where it is commonly known as ...

derivative.

Thiophene-2-carboxylic acid Thiophene-2-carboxylic acid is an organic compound with the formula SC4H3CO2H. It is one of two monocarboxylic acids of thiophene, the other being thiophene-3-carboxylic acid. Copper(I) thiophene-2-carboxylate is a catalyst for Ullmann coupling ...

is the final major metabolic product. It is very

hydrophilic A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press. In contrast, hydrophobes are no ...

and is excreted in urine. Methiopropamine and especially thiopropamine are also excreted renally, unchanged.

Synthesis

There is a four-step synthesis of methiopropamine. It begins with (thiophen-2-yl)magnesium bromide, which is reacted with propylene oxide, yielding 1-(thiophen-2-yl)-2-hydroxypropane which is reacted with phosphorus tribromide, yielding 1-(thiophen-2-yl)-2-bromopropane which is finally reacted with

methylamine Methylamine is an organic compound with a formula of . This colorless gas is a derivative of ammonia, but with one hydrogen atom being replaced by a methyl group. It is the simplest primary amine. Methylamine is sold as a solution in methanol, ...

, yielding 1-(thiophen-2-yl)-2-methylaminopropane. Methiopropamine synthesis

Legal status

China

As of October 2015 MPA is a controlled substance in China.

Finland

Methiopropamine is illegal in Finland.

Germany

Methiopropamine is explicitly illegal in Germany.

United Kingdom

Following the ban on ethylphenidate, authorities noticed an increase in methiopropamine use by injecting users. The ACMD suggested it be banned on 18 November 2015 as it had similar effects to ethylphenidate. The government enacted a temporary drug control order a week later which came into force on 27 November 2015. Though ordinarily the TCDO would only last 1 year, the ACMD reported that since its invocation prevalence of MPA had significantly decreased, and that it had been challenging to collect information about the drug. As a result of this, they requested that the TCDO be extended a further year. Methiopropanine was made a Class B controlled drug under the Misuse of Drugs Act 1971 (as amended) (Amendment)(No.2) Order 2017 I 2017/1114 this came into effect on the 27th of November 2017.

United States

Methiopropamine is scheduled at the federal level in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

.21 CFR — SCHEDULES OF CONTROLLED SUBSTANCES §1308.11 Schedule I.
/ref> The DEA had planned to place methiopropamine in Schedule I of Controlled Substances and was accepting public comments until October 4, 2021. Later, the compound was placed in Schedule I.

Florida

Methiopropamine is a Schedule I controlled substance in the state of

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

making it illegal to buy, sell, or possess in Florida.Florida Statutes - Chapter 893 - DRUG ABUSE PREVENTION AND CONTROL
/ref> Tasmania (Australia) Methiopropamine is a "controlled substance" and therefore an "illegal drug" to import, possess or sell/traffic in without express authority of the relevant government agency.

References

{{Stimulants Amines Stimulants Thiophenes Designer drugs Norepinephrine–dopamine reuptake inhibitors