Methylone is a beta-ketone analogue of MDMA (Ecstasy).  It is also known as bk-MDMA, M1, or MDMCat. The more intuitive abbreviation MDMC unfortunately can not be used for this chemical, since it had already been given to another earlier Shulgin creation, 3,4-ethylenedioxymethmphetamine (PIHKAL #110). It is more properly known as 3,4-methylenedioxymethcathinone. Methylone is related to methcathinone as MDMA is related to methamphetamine and MDA is to amphetamine. 
In spite of some substantial pharmacokinetic differences (its dopaminergic activity is far more pronounced relative to its serotonergic activity), methylone is an empathogen-like drug and a mild stimulant, producing effects similar to, yet less intense than MDMA.
Methylenedioxymethcathinone
Diethylcathinone
4-Methylmethcathinone
Chlormadinone
Nitisinone
Methcathinone
Methylrosaniline
Phendimetrazine