4-Methylthiomethamphetamine

4-Methylthiomethamphetamine (4-MTMA; code name PAL-1063), also known as N-methyl-4-methylthioamphetamine (NMMTA), is a monoamine releasing agent (MRA) of the amphetamine family related to 4-methylthioamphetamine (4-MTA) and N,N-dimethyl-4-methylthioamphetamine (DMMTA or 4-MTDMA).^[1][2][3] Much less is known about 4-MTMA compared to 4-MTA.^[4]

4-Methylthiomethamphetamine

Clinical data
Other names	4-MTMA; N-Methyl-4-methylthioamphetamine; N-Methyl-MTA; NMMTA; PAL-1063; PAL1063
Drug class	Serotonin releasing agent; Monoamine oxidase inhibitor; Entactogen
Identifiers
IUPAC name N-methyl-1-(4-methylsulfanylphenyl)propan-2-amine
CAS Number	547736-90-3
PubChem CID	46882957
ChemSpider	24678465
ChEMBL	ChEMBL1078038
Chemical and physical data
Formula	C11H17NS
Molar mass	195.32 g·mol−1
3D model (JSmol)	Interactive image
SMILES CC(CC1=CC=C(C=C1)SC)NC
InChI InChI=1S/C11H17NS/c1-9(12-2)8-10-4-6-11(13-3)7-5-10/h4-7,9,12H,8H2,1-3H3 Key:WWHIYWVWPXXBTC-UHFFFAOYSA-N

4-MTMA is known to act as a potent serotonin releasing agent (SRA).^[1][3] Its EC₅₀Tooltip half-maximal effective concentration value for induction of serotonin release in rat brain synaptosomes was 21 nM, whereas norepinephrine and dopamine release were not reported.^[3] In addition to its MRA activity, like 4-MTA, the drug has been found to act as a potent reversible enzyme inhibitor of monoamine oxidase A (MAO-A).^[4][5][6] It is about one-third as potent as 4-MTA as an MAO-A inhibitor.^[5][6] Its IC₅₀Tooltip half-maximal inhibitory concentration value for MAO-A inhibition is 0.89 nM, whereas the values of 4-MTA are 0.13 nM for (+)-4-MTA and 2.04 nM for (–)-4-MTA.^[5][6] Neither 4-MTA nor 4-MTMA inhibited monoamine oxidase B (MAO-B).^[5][6] Potent monoamine oxidase inhibition by amphetamines has been associated with dangerous and sometimes fatal toxicity in humans.^[5][6]

In animal drug discrimination tests, 4-MTA and 4-MTMA were found to generalize to MDMA.^[4][2][7] 4-MTA substituted for the serotonergic agent PMMA, whereas 4-MTMA did not.^[4][2][7] 4-MTA did not substitute for the serotonergic psychedelic DOM, whereas 4-MTMA was not assessed in DOM-trained animals.^[4][2] Neither 4-MTA nor 4-MTMA substituted for the psychostimulants dextroamphetamine or cocaine.^[4][2] It was concluded that 4-MTA and 4-MTMA show mainly MDMA-like effects in rodents.^[4][2][7]

4-MTMA had not been identified as an illicit drug or drug of misuse by 2004.^[2][1] However, it is said to have been encountered as a novel designer drug by 2015.^[8]