Methcathinone

Methcathinone was first synthesized in 1928 in the United States^[3] and was patented by Parke-Davis in 1957.^[4] It was used in the Soviet Union during the 1930s and 1940s as an anti-depressant (under the name Эфедрон—ephedrone). Methcathinone has long been used as a drug of abuse in the Soviet Union and Russia.^{[citation needed]}

Circa 1994, the United States government recommended to the UN Secretary-General that methcathinone should be listed as a Schedule I controlled substance in the Convention on Psychotropic Substances.^[5] In 1995, following US advice, China added the drug to its list of prohibited substances and discontinued its pharmaceutical use.^[6]

Methcathinone is a beta-keto N-methylamphetamine and is closely related to the naturally occurring compounds, cathinone and cathine. It is also very closely related to methamphetamine, differing by only the β-ketone substituent and differing from amphetamine by both a keto and N-methyl substituent. Its carbon skeleton is identical to pseudoephedrine and methamphetamine. It differs from pseudoephedrine in that the hydroxide beta to the aromatic ring is oxidized to a ketone.

Methcathinone possesses a chiral carbon atom, and therefore two enantiomers are possible. When it is made semi-synthetically from pseudo/ephedrine as a starting material, then only a single enantiomer is produced. Given that the chiral center has an alpha hydrogen and adjacent the carbonyl group, the molecule will racemize in solution via an enol intermediate. This process is known as keto–enol tautomerism.

Methcathinone production utilizes the oxidation of pseudoephedrine or ephedrine, the former being preferred because of much higher yields achieved. Oxidation of pseudoephedrine to methcathinone requires little chemistry experience, making it (relatively) easy to synthesize.^{[7][unreliable source?]} Potassium permanganate (KMnO₄) is most commonly used as the oxidant.

In clandestine laboratories, synthesizing methcathinone using potassium permanganate is considered undesirable because of the low yields and the high toxicity of this oxidant (see Manganese toxicity); however, if done in a proper laboratory using the proper procedures potassium permanganate can be a high-yielding reactant. A method that yields more methcathinone is oxidizing (pseudo)ephedrine with chromium (VI) compounds, which are far more toxic than permanganate compounds.

Methcathinone as free base is very unstable; it easily loses its ketone group, which is substituted with a hydroxyl group, yielding pseudoephedrine, in the reverse of the typical synthesis reaction. Structurally, this occurs when the C=O bond at the Rβ-position is converted into a C-OH bond. Additionally, a dimerization reaction has been observed in solutions of freebase methcathinone, which yields a biologically inactive compound.^[8]

Methcathinone hydrochloride increases spontaneous rodent locomotor activity,^[9] potentiates the release of dopamine from dopaminergic nerve terminals in the brain,^[9] and causes appetite suppression.^{[citation needed]} Users can easily forget to consume fluids leading to increased thirst and dehydration. The effects of methcathinone are similar to those of methamphetamine, initially deemed to be less intense by the inexperienced user, and often more euphoric.^{[citation needed]} The effects have been compared to those of cocaine, since it commonly causes hypertension (elevated blood pressure) and tachycardia (elevated heart rate).

Reported effects include:^{[medical citation needed]}

• Feelings of euphoria
• Increased alertness
• Slurred speech
• Shaking of the limbs
• Increased heart rate
• Increased blood pressure, risk of stroke or heart attack
• Increased empathy and sense of communication
• Both decreased and increased sexual function and desire
• Bruxism

The effects of methcathinone usually last from four to six hours.^{[citation needed]}

Methcathinone has very strong affinities for the dopamine transporter and the norepinephrine (noradrenaline) transporter. Its affinity for the serotonin transporter is less than that of methamphetamine.^[10]

The C=O bond at the R_β-position (directly right of the phenyl ring) is slightly polar, and as a result the drug does not cross the lipid blood–brain barrier quite as well as amphetamine.^{[citation needed]} Nevertheless, it is a potent central nervous system (CNS) stimulant and dopamine reuptake inhibitor. Chronic high dosage use may result in acute mental confusion ranging from mild paranoia to psychosis.^{[citation needed]} These symptoms typically disappear quickly if use is stopped.

Anecdotal reports have provided some information on patterns of methcathinone use. The most common route of administration is via nasal insufflation (snorting).^{[citation needed]} Other routes of administration include oral, IV injection and smoking.

Methcathinone binges resemble amphetamine binges in that the user may not sleep or eat, and takes in little in the way of liquids. The methcathinone binge is followed by long periods of sleep, excess eating, long-lasting nosebleeds (insufflation of methcathinone is corrosive to the nasal mucosa in the same manner as methamphetamine) and, in some cases, depression.^{[citation needed]}

In preclinical studies, methcathinone hydrochloride produces an abuse potential similar to that of the amphetamines.^[11]

Methcathinone can be highly psychologically addictive, and can produce a methamphetamine-like withdrawal.

In drug discrimination studies, methcathinone hydrochloride evokes responses similar to those induced by both dextro­amphetamine sulfate and cocaine hydrochloride.

Injecting this substance has been associated with symptoms similar to those seen in patients with Parkinson's disease (manganism) due to the compound manganese dioxide which is a byproduct of synthesis with permanganate.^[12]

The Convention on Psychotropic Substances lists methcathinone as a Schedule I substance which restricts its use for government-approved medical and scientific uses.^[13]

Methcathinone is a Schedule 9 prohibited substance in Australia under the Poisons Standard (February 2021).^[14] A Schedule 9 substance is defined as a substance which may be abused or misused, the manufacture, possession, sale or use of which should be prohibited by law except when required for medical or scientific research, or for analytical, teaching or training purposes with approval of Commonwealth and/or State or Territory Health Authorities.^[14]

In the United Kingdom, methcathinone is listed as a Class B drug with no clinical uses.^[15]

In the United States, methcathinone is listed as a Schedule I drug, for which there is no clinical use.^[16]

In the Netherlands, methcathinone is listed as a Level I substance of the Opium Law, for which there is no clinical use.

• Substituted cathinone

• Cathinone & Methcathinone from Erowid
• International Drug Scheduling; Convention on Psychotropic Substances; Certain Stimulant/Hallucinogenic Drugs and Certain Nonbarbiturate Sedative Drugs, Food and Drug Administration, June 20, 1994.
• Methcathinone from lycaeum