A group of scientist from Hungary and Austria investigated the binding of MDMA synthesis byproducts to the pharmaclogical target of MDMA, the human serotonin transporter. Two compounds inhibited the release of serotonin which is the primary effect of MDMA. These compounds 1,3-bis(3,4-methylenedioxyphenyl)-2-propanamine and N-formyl-1,3-bis (3,4-methylenedioxyphenyl)-prop-2-yl-amine are synthesis byproducts when MDMA resp. MDA is synthesized from piperonal. All other tested byproducts had no relevant affinity to the monoamine transporter. According to the data from the article it is not very likely that synthesis byproducts are responsible for the toxicity of ecstasy.

Original article: http://dx.doi.org/10.1124/jpet.105.084426.