6-MeO-RU-28306, or 6-methoxy-RU-28306, also known as 4,ñ-methylene-5-methoxy-N,N-dimethyltryptamine (4,ñ-methylene-5-MeO-DMT), is a serotonin receptor modulator and a cyclized tryptamine and partial ergoline. It is the 6-methoxy derivative of RU-28306 (4,ñ-methylene-DMT) and a cyclized derivative of 5-MeO-DMT. The drug showed affinity for the serotonin-labeled serotonin 5-HT<sub>1</sub> receptors and spiperone-labeled serotonin 5-HT<sub>2</sub> receptors in rat frontal cortex membranes in vitro ( = 96nM and 1,756nM, respectively). 6-MeO-RU-28306 robustly reduced hypothalamic 5-hydroxyindoleacetic acid (5-HIAA) levels and increased circulating corticosterone levels in rodents in vivo, which are both measures of serotonin receptor agonist activity. The chemical synthesis of 6-MeO-RU-28306 has been described. 6-MeO-RU-28306 was first described in the scientific literature by 1988.