Methylone (3, 4-Methylenedioxy-N-methylcathinone), a β-keto analog of 3,4-methylenedioxy-N-methylamphetamine (MDMA) is a stimulant and psychoactive drug. Methylone is a popular drug of abuse that strongly increases the release of the three monoamines: dopamine, serotonin (5-HT) and norepinephrine. In addition, methylone inhibits plasma membrane catecholamine transporters but only weakly inhibit the vesicle transporter. In April 2013, methylone was listed in the Schedule 1 substance under the Controlled Substances Act.

SCH-23390 is a potent and selective antagonist of the D1A and D1B dopamine receptors having Ki of 0.2 and 0.3 nM respectively. The C11 radiolabeled version has proven to be useful as a PET imaging probe in humans for the investigation of a number of neurological conditions including Schizophrenia, Parkinson's Disease, and Huntington's Disease. It should be noted that the non-radiolabeled compound did receive preclinical interest as a potential therapeutic (annotated separately), although such efforts have been discontinued due to side-effects and a lack of therapeutic efficacy.