The focus of this report is on the compound TDIQ and conformationally restricted analogs of amphetamine, DOM and DOB, and the report covers a series of drug discrimination studies in rats and a radioligand binding profile of TDIQ. Number of responses on drug-appropriate lever and number of rats reaching criterion were recorded for training and test drug, with discrimination defined as >80% on the drug-appropriate lever after drug and <20% on drug-appropriate lever after saline. Rats trained to distinguish 1.5 mg/kg i.p. MDMA from saline did not show stimulus generalization to conformationally restricted versions of amphetamine, methamphetamine, DOM or DOB. However, a conformationally restricted form of PMMA (PMMA/CR) generalized to the MDMA stimulus, with 3 mg/kg PMMA/CR producing 83% MDMA-appropriate responding. On the other hand, stimulus generalization occurred in TDIQ trained rats with conformationally restricted versions of DOM, DOB, and PMMA, but not the conformationally restricted version of methamphetamine (METH/CR) or N-methyl-DOM/CR. A radioligand assay of TDIQ found that its strongest affinity is for alpha2 receptors, and a weaker affinity was found for D3 receptors. It did not bind to 5HT, DA or NE transporters, to any 5HT receptors, or to all other DA and NE receptors. The findings of this report suggest that adrenergic action, and specifically alpha2 activity, may be involved in producing part of the MDMA stimulus in rats. Findings from rat drug discrimination studies have led Glennon to posit that PMMA may be a prototypical entactogen. However, rats have generalized the MDMA stimulus to fenfluramine, whereas people do not appear to make the same generalization, suggesting that rats and humans do not attend to the same stimulus characteristics.