Phenylbutenamine, or 4-phenylbut-3-en-2-amine, is a monoamine releasing agent (MRA) of the arylalkylamine family related to ò-phenethylamine and amphetamine. It has two possible stereoisomers: (3E)-phenylbutenamine (PAL-881) and (3Z)-phenylbutenamine (PAL-893). Both of these enantiomers act as norepinephrineâÂÂdopamine releasing agents (NDRAs), and to similar comparative extents, albeit with far lower potency than ò-phenethylamine or amphetamine.