Metazocine is an

opioid Opioids are a class of Drug, drugs that derive from, or mimic, natural substances found in the Papaver somniferum, opium poppy plant. Opioids work on opioid receptors in the brain and other organs to produce a variety of morphine-like effects, ...

analgesic An analgesic drug, also called simply an analgesic, antalgic, pain reliever, or painkiller, is any member of the group of drugs used for pain management. Analgesics are conceptually distinct from anesthetics, which temporarily reduce, and in s ...

related to

pentazocine Pentazocine, sold under the brand name Talwin among others, is an analgesic medication used to treat moderate to severe pain. It is believed to work by activating (agonizing) κ-opioid receptors (KOR) and μ-opioid receptors (MOR). As such it i ...

. While metazocine has significant analgesic effects, mediated through a mixed

agonist–antagonist In pharmacology the term agonist-antagonist or mixed agonist/antagonist is used to refer to a drug which under some conditions behaves as an agonist (a substance that fully activates the receptor that it binds to) while under other conditions, beh ...

action at the mu opioid receptor, its clinical use is limited by

dysphoric Dysphoria (; ) is a profound state of unease or dissatisfaction. It is the semantic opposite of euphoria. In a psychiatric context, dysphoria may accompany depression, anxiety, or agitation. In psychiatry Intense states of distress and uneas ...

and

hallucinogenic Hallucinogens, also known as psychedelics, entheogens, or historically as psychotomimetics, are a large and diverse class of psychoactive drugs that can produce altered states of consciousness characterized by major alterations in thought, moo ...

effects which are most likely caused by activity at

kappa opioid receptor Kappa (; uppercase Κ, lowercase κ or cursive ; , ''káppa'') is the tenth letter of the Greek alphabet, representing the voiceless velar plosive sound in Ancient and Modern Greek. In the system of Greek numerals, has a value of 20. It was d ...

s (where it is a high-efficacy agonist) and/or

sigma receptor Sigma receptors (σ-receptors) are protein receptors that bind ligands such as 4-PPBP (4-phenyl-1-(4-phenylbutyl) piperidine), SA 4503 (cutamesine), ditolylguanidine, dimethyltryptamine, and siramesine. There are two subtypes, sigma-1 rec ...

s. Metazocine is in Schedule II of the Controlled Substances Act 1970 of the United States as a Narcotic with ACSCN 9240 with a 19 gram aggregate manufacturing quota as of 2014. The free base conversion ratio for salts includes 0.81 for the hydrochloride and 0.74 for the hydrobromide. It is listed under the Single Convention for the Control of Narcotic Substances 1961 and is controlled in most countries in the same fashion as is morphine.

Syntheses

The

benzomorphan Benzomorphan is a chemical compound that is the base for a series of drugs which variably act on the sigma receptors and κ-opioid receptors, including the following compounds: * 5,9-DEHB * 8-CAC * Alazocine * Anazocine * Bremazocine * Buti ...

, metazocine (6), can be obtained from a variation of the

morphinan Morphinan is the prototype chemical structure of a large chemical class of psychoactive drugs, consisting of opiate analgesics, cough suppressants, and dissociative hallucinogens, among others. Typical examples include compounds such as morphine, ...

synthesis Synthesis or synthesize may refer to: Science Chemistry and biochemistry *Chemical synthesis, the execution of chemical reactions to form a more complex molecule from chemical precursors **Organic synthesis, the chemical synthesis of organi ...

. :

Reaction of the

Grignard reagent Grignard reagents or Grignard compounds are chemical compounds with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromi ...

from ''p''-methoxybenzyl chloride (1) with the

lutidine Lutidine is the trivial name used to describe the chemical compounds which are dimethyl derivatives of pyridine. They were discovered in Dippel's oil and named (as an anagram of toluidine, with which they share their empirical formula) by Thomas ...

methiodide (2) affords the benzylated dihydropyridine (3). Reduction of the

enamine An enamine is an unsaturated compound derived by the condensation of an aldehyde or ketone with a secondary amine. Enamines are versatile intermediates. The word "enamine" is derived from the affix ''en''-, used as the suffix of alkene, and the r ...

π-bond In chemistry, pi bonds (π bonds) are covalent chemical bonds, in each of which two lobes of an orbital on one atom overlap with two lobes of an orbital on another atom, and in which this overlap occurs laterally. Each of these atomic orbitals ...

leads to the

tetrahydropyridine Tetrahydropyridines (or piperideines) are heterocycles with the formula . Three isomers exist, which differ by the location of the double bond. None of the parent species occur widely, so they are mainly of theoretical interest. Although the pa ...

(4). Cyclization by means of acid leads directly to the benzomorphan ring system (5).

Demethylation 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 at ...

of the aromatic ring system gives the

phenol Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire. The molecule consists of a phenyl group () ...

. Although this last compound is in fact a relatively potent analgesic, it is not available commercially as a

drug A drug is any chemical substance other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Consumption of drugs can be via insufflation (medicine), inhalation, drug i ...

. Also see:Singh, Kamal Nain; Singh, Pushpinder; Sharma, Arvind Kumar; Singh, Paramjit; Kessar, Satinder V. (2010). "A Short Synthesis of Benzomorphane Analgesics (±)-Metazocine and (±)-Phenazocine". Synthetic Communications. 40 (24): 3716–3720. doi:10.1080/00397910903531722.

References

{{Opioidergics Benzomorphans Kappa-opioid receptor agonists Hydroxyarenes Synthetic opioids

Syntheses

See also

References