THC acetate ester (THC-O-acetate, THC acetate, O-acetyl-THC, THC-O, ATHC) is the

acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetallic or radical base). "Acetate" also describes the conjugate base or ion (specifically, the negatively charged ion called ...

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...

THC Tetrahydrocannabinol (THC) is the principal psychoactive constituent of cannabis and one of at least 113 total cannabinoids identified on the plant. Although the chemical formula for THC (C21H30O2) describes multiple isomers, the term ''THC' ...

Physical data, chemistry, and properties

THC acetate ester (THC-O or THCOA) can be synthesized from

, or from THCA. The acetylation of THC does not change the properties of the compound to the same extent as with other acetate esters, as the parent compound (THC) is already highly

lipophilic Lipophilicity (from Greek λίπος "fat" and φίλος "friendly"), refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. Such non-polar solvents are themselves lipo ...

, but potency is nonetheless increased to some extent. While the acetate ester of delta-9-THC is the best studied, the acetate esters of other isomers, especially

delta-8-THC Delta-8-tetrahydrocannabinol (delta-8-THC, Δ8-THC) is a psychoactive cannabinoid found in the Cannabis plant. It is an isomer of delta-9-tetrahydrocannabinol (delta-9-THC, Δ9-THC), the compound commonly known as THC. ∆8-THC is under prelim ...

but also

delta-10-THC Delta-10-Tetrahydrocannabinol (Delta-10-THC, Δ10-THC, alternatively numbered as Δ2-THC) is an isomer of tetrahydrocannabinol, discovered in the 1980s. Two enantiomers have been reported in the literature, with the 9-methyl group in either the ( ...

are also known, as are other esters such as THC-O-phosphate, THC hemisuccinate and THC morpholinylbutyrate.

History

THC acetate ester was investigated as a possible non-lethal incapacitating agent as part of the

Edgewood Arsenal experiments From 1948 to 1975, the U.S. Army Chemical Corps conducted classified human subject research at the Edgewood Arsenal facility in Maryland. The purpose was to evaluate the impact of low-dose chemical warfare agents on military personnel and to tes ...

at some point between 1949 and 1975. It was noted to have about twice the capacity to produce

ataxia Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of ...

(lack of voluntary coordination of muscle movements) as did

when administered to dogs. Author D. Gold provided synthesis instructions for this compound (calling it "THC acetate") in his 1974 book ''Cannabis Alchemy: Art of Modern Hashmaking'', in which it is described as follows; The U.S. DEA first encountered THC-O-acetate as an apparent controlled substance analogue of THC in 1978. It was made in an analogous manner to how aspirin (

acetylsalicylic acid Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat ...

) is made from willow bark ( salicylic acid). The incident was described by Donald A. Cooper of the DEA thus: A similar case reported in June 1995 in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

, and THC-O-acetate was ruled to be a Class A drug in that case. The description of that case appears to indicate the convicted manufacturer was using D. Gold's book ''Cannabis Alchemy'' as a guide. THC acetate was also reported to have been found by

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

police in 1995, again made by acetylation of purified cannabis extracts with acetic anhydride. Following legal changes in the USA since around 2018, especially the legalisation of cannabis in an increasing number of states and the passage of the

2018 Farm Bill The 2018 farm bill or Agriculture Improvement Act of 2018 is an enacted United States farm bill that reauthorized $867 billion for many expenditures approved in the prior farm bill (the Agricultural Act of 2014). The bill was passed by the Senat ...

which eased restrictions on the cultivation of industrial hemp, THC-O-acetate has become increasingly available as a recreational drug, initially in the USA but subsequently in other countries also. It may be produced from extracts of psychoactive strains of cannabis in states where this is permitted, in which case the product will be primarily O-acetyl-Δ⁹-THC, but it is also commonly produced from

Delta-8-THC Delta-8-tetrahydrocannabinol (delta-8-THC, Δ8-THC) is a psychoactive cannabinoid found in the Cannabis plant. It is an isomer of delta-9-tetrahydrocannabinol (delta-9-THC, Δ9-THC), the compound commonly known as THC. ∆8-THC is under prelim ...

which is synthesised from

cannabidiol Cannabidiol (CBD) is a phytocannabinoid discovered in 1940. It is one of 113 identified cannabinoids in cannabis plants, along with tetrahydrocannabinol (THC), and accounts for up to 40% of the plant's extract. , clinical research on CBD in ...

extracted from hemp, in which case the product will be primarily O-acetyl-Δ⁸-THC. Since Δ⁹-THC and Δ⁸-THC are quite different in potency, the corresponding acetylated derivatives also will be, which may pose risks to consumers who are unaware of which isomer is in commercial products. Concerns have also been raised about the lack of safety data or quality control testing given the limited history of human use and potentially toxic chemical reagents used during manufacture. The legal issue of whether purified THC-O-acetate is considered legal in jurisdictions where cannabis is legal is also complex and varies between jurisdictions.

Toxicity

According to researchers at

Portland State University Portland State University (PSU) is a public research university in Portland, Oregon. It was founded in 1946 as a post-secondary educational institution for World War II veterans. It evolved into a four-year college over the following two decad ...

who screened for the presence of reacted

ketene In organic chemistry, a ketene is an organic compound of the form , where R and R' are two arbitrary monovalent chemical groups (or two separate substitution sites in the same molecule). The name may also refer to the specific compound ethen ...

as N-benzylacetamide reported that THC-O-Acetate, Vitamin E Acetate, CBD-acetate, and CBN-acetate, may break down to release ketene gas when heated at . Ketene gas is potentially lethal at 5 parts per million

Legal status

United Kingdom

THC-O-acetate is a Class B drug in the

United States

THC-O-acetate is not 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 territori ...

, but it could be considered an analog of

, in which case purchase, sale, or possession could be prosecuted under the

Federal Analog Act The Federal Analogue Act, , is a section of the United States Controlled Substances Act passed in 1986 which allows any chemical "substantially similar" to a controlled substance listed in Schedule I or II to be treated as if it were listed in ...

. In the

9th Circuit Court of Appeals The United States Court of Appeals for the Ninth Circuit (in case citations, 9th Cir.) is the U.S. federal court of appeals that has appellate jurisdiction over the U.S. district courts in the following federal judicial districts: * District ...

, the Court found that ∆8-THC is a legal product under the

and may receive patent and copyright protections. This is the first time a federal appellate court has recognized the legality of hemp-derived cannabinoids other than CBD, and may serve to instruct other

appellate courts A court of appeals, also called a court of appeal, appellate court, appeal court, court of second instance or second instance court, is any court of law that is empowered to hear an appeal of a trial court or other lower tribunal. In much of ...

in subsequent rulings.

References

{{DEFAULTSORT:Thc-O-Acetate Cannabinoids Acetate esters Benzochromenes Prodrugs Heterocyclic compounds with 3 rings