The acetylation of opium with acetic anhydride, which converts morphine to heroin, produces a variety of other acetylated products from other endogenous alkaloids, including thebaine. ATM4 4-acetoxy analog is a major product of the acetylation of thebaine using acetic anhydride. It is the precursor of the acetylated thebaine metabolite ATM4, which is generated during phase I metabolism of ATM4 4-acetoxy analog by human liver microsomes. The physiological and toxicological properties of this compound are not known. This product is intended for forensic and research purposes.