Substituted methylenedioxyphenethylamine

The substituted methylenedioxyphenethylamines (abbreviated as MDxx) represent a diverse chemical class of compounds derived from phenethylamines.

This category encompasses numerous psychoactive substances with entactogenic, psychedelic, and/or stimulant properties, in addition to entheogens.

These compounds find application as research chemicals, designer drugs, and recreational substances.

Other notable MDxx class substances include 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA; "Eve"), N-methyl-1,3-benzodioxolylbutanamine (MBDB; "Eden"), and 3,4-methylenedioxy-N-methylcathinone (βk-MDMA; "Methylone").

Like amphetamines and cathinones, MDxx compounds derive most if not all of their stimulant effects from the phenylethylamine core, in fact most MDxx compounds can also be grouped with cathinones and or amphetamines due to having similar functional groups, but in most cases any compound with a methylenedioxy group attached will be grouped as an MDxx compound due to the unique hallucinogenic and empathogenic/entactogenic effects that are not present in most other amphetamines and present to a lesser extent in most cathinones.