THC-O-acetate

THC-O-acetate is the acetate ester of THC. The term THC-O-acetate is commonly used for two different isomers of this substance, dependent on which isomer of THC it is synthesized from. The difference between Δ⁸-THC and Δ⁹-THC is the location of the double bond within the cyclohexene ring system. In naming the esters of THC, the "-O-" is superfluous.

Physical data, chemistry, and properties

Image:D8-THC-O-acetate.svg|class=skin-invert-image|200px|thumb|left|O-acetyl-Δ⁸-THC, CAS# 23050-54-6
[Image:THC-esters structure.png|class=skin-invert-image|200px|thumb|left|Esters of Δ⁹-THC: Top (from left); THC acetate, THC propionate, THC phosphate, THC-NE, Bottom; THC morpholinylbutyrate, THC piperidinylpropionate, THC hemisuccinate, THC hemiglutarate]
THC acetate ester can be synthesized from THC, 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 is already highly lipophilic, but potency is nonetheless increased to some extent. While the acetate ester of Δ⁹-THC is the best studied, the acetate esters of other isomers, especially Δ⁸-THC but also Δ¹⁰-THC are also known, as are other esters such as THC-O-propionate, THC-O-phosphate, THC hemisuccinate, THC hemiglutarate, THC morpholinylbutyrate, THC piperidinylpropionate, THC naphthoyl ester, and THC-VHS, as well as the hydrogenated derivative HHC-O-acetate and the ring-expanded Abeo-HHC acetate, as well as related compounds such as THC methylcarbonate.

Pharmacology

It is a metabolic pro-drug, with its subjective effects being felt around 30 minutes after ingestion.

Psychedelic claims

In a 2023 study, anecdotal claims surrounding THC-O-acetate's supposed ability to initiate psychedelic experiences were shown to not be significant. Answers using the Mystical Experience Questionnaire were under the threshold of a true experience, and those who had used classical psychedelics such as LSD or psilocybin consistently scored lower on the MEQ. When asked directly, 79% of the participants said it was either "not at all" or "a little" like a psychedelic experience.

History

This substance was investigated as a possible non-lethal incapacitating agent as part of the Edgewood Arsenal experiments at some point between 1949 and 1975. It was noted to have about twice the capacity to produce ataxia as did THC when administered to dogs.
Author D. Gold provided synthesis instructions for this compound 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 was first made from willow bark extract in the 1800s. The incident was described by Donald A. Cooper of the DEA thus:
A similar case reported in June 1995 in the United Kingdom.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 police in 1995, again made by acetylation of purified cannabis extracts with acetic anhydride.
With passage of the 2018 [United States farm bill], ∆8-THC-O-acetate based vaporizers and edibles have become increasingly available in the United States and are now commonly sold at convenience stores and gas stations.

Toxicity

In 2022, researchers at Portland State University used an e-nail to vaporize CBD-acetate, CBN-acetate, and THC-O-acetate to screen for the presence of ketene formation when vaporizing. They reported that just like Vitamin E acetate, all three of these cannabinoid acetates produced ketene gas when heated. For this reason, the inhalation of THC-O-acetate based products could be hazardous to health.

Legal status

United Kingdom

THC-O-acetate is a Class B drug in the United Kingdom.

United States

The legal status of THC-O is in dispute within the United States. Since 2023, the Drug Enforcement Administration has held the position that it is a controlled substance because "delta-9-THCO and delta-8-THCO do not occur naturally in the cannabis plant and can only be obtained synthetically". In September 2024, being the first court case specifically addressing this issue, the United States Court of Appeals for the Fourth Circuit rejected the foregoing DEA position and "set a legal hemp standard" by holding that THC-O is legal. The issue of THC-O legality has not been addressed by other circuits or by the Supreme Court and there remains a "hazy legal landscape" for hemp derived psychotropic products.

Germany

On 27 June 2024, following the Ban of HHC, THC-O-Acetate was added to both the annex of New Psychoactive Substances Act (NpSG) and the Narcotic Drugs Act (BtMG) since it was not a naturally occurring cannabinoid.
Manufacture, sale and possession of the cannabinoid has since been fully outlawed.