2C-B-morpholine

2C-B-morpholine, also known as 2C-B-norphenmetrazine or as 2-(4-bromo-2,5-dimethoxyphenyl)morpholine, is a serotonin receptor modulator of the phenylmorpholine (phenmetrazine) and cyclized phenethylamine groups. It is a ligand of the serotonin 5-HT_2A receptor, with an affinity of 20.6 nM and an E_maxTooltip maximal efficacy of 4%. The drug showed 103-fold lower affinity for this receptor than R(–)-DOB and had minimal agonist activity (with R(–)-DOB having an E_max of 51% in the assay), so for practical purposes would act as an antagonist at the 5-HT_2A receptor under most circumstances, despite being technically classified as a partial agonist. 2C-B-morpholine was first described in the scientific literature by Richard Glennon and colleagues by 2004.