A series of NJ-dialkyltryptamines with methylthio or methylenedioxy substituents in the 4, 5, and 6 positions and methyl or isopropyl on the side-chain nitrogen has been synthesized. The behavioral pharmacology of these compounds showed them to possess Bovet-Gatti profiles characteristic of hallucinogens, and the 5-methylthio congener was the most potent. Binding studies at [3H] LSD and [3H] 5-HT sites demonstrated that no single structural ...