4-Thioisomescaline (4-TIM), also known as 2,3-dimethoxy-4-methylthiophenethylamine, is a chemical compound of the phenethylamine and scaline families related to mescaline. It is the analogue of isomescaline in which the methoxy group at the 4 position has been replaced with a methylthio group. The compound is one of two possible thioisomescaline (TIM) positional isomers, the others being 3-thioisomescaline (3-TIM) and 4-thioisomescaline (4-TIM).
In his book PiHKAL (Phenethylamines I Have Known and Loved) and other publications, Alexander Shulgin lists 4-TIM's dose as greater than 160 or 240mg orally and its duration as unknown. The compound was completely inactive at tested doses. Shulgin concluded that 4-TIM is inactive.
The chemical synthesis of 4-TIM has been described.
4-TIM was first described in the scientific literature by Shulgin and Peyton Jacob III in 1981. Subsequently, it was described in greater detail by Shulgin in PiHKAL in 1991.