THC gives an acetate (ATHC) which is as potent as THC. The mental effects are quite subtle and pleasant. Wohlner, et al., prepared ATHC by refluxing the crude distillate of cannabis oil with approximately 3 volumes of acetic anhydride. It is purified by distillation i.v. or with steam.
Cahn prepared ATHC thus: add 150 ml acetyl chloride (dropwise with stirring and cooling) to 185 gr crude resin in 500 ml dry pyridine. Crystals may separate during the addition, or on standing a few hours at room temperature. Pour the mixture into dilute hydrochloric acid/ice. Separate the oil, then dissolve it in ether. Wash this solution with dilute acid, then with aqueous sodium carbonate, and again with water. Dry the solution with calcium chloride. Strip the solvent and distill the residue (240-270 C°/20 mm). The mixture of acetylated cannabinoids is separated by dissolving 2 gr in 100 ml benzene and chromatography over silica (150-200 mesh). Elute with 800 ml benzene. Combine the washings and the original effluent solutions, then strip the benzene i.v. to recover about 60% yield of light yellow oil. The material remaining on the column contains CBD and other cannabinoid acetates which can be recovered with ethanol and worked up.(21)
Acetylation refers to the process of introducing an acetyl group (resulting in an acetoxy group) into a compound, namely the substitution of an acetyl group for an active hydrogen atom. A reaction involving the replacement of the hydrogen atom of a hydroxyl group with an acetyl group (CH3 CO) yields a specific ester, the acetate. Acetic anhydride is commonly used as an acetylating agent reacting with free hydroxyl groups. For example, it is used in the synthesis of aspirin, heroin, and THC-O-acetate.