Synthesis and in vitro toxicity of 4-MTA, its characteristic clandestine synthesis byproducts and related sulfur substituted alpha-alkylthioamphetamines.

4-Methylthioamphetamine (4-MTA) is recognised as a 3,4-methylenedioxymethamphetamine (MDMA)-like drug of abuse. Such amphetamine-type drugs often contain byproducts of uncontrolled, illegal clandestine synthetic processes. We report the isolation and structural identification of a number of novel pyridines, dihydropyridone and N,N-di(1-aryl-2-propyl) amines as route-specific byproducts associated with clandestine synthesis of 4-MTA and related amphetamines. We report the in vitro cytotoxicity of 4-MTA, its synthesis byproducts together with some structurally related sulfur substituted alpha-alkyl phenethylamines in cell lines overexpressing human monoamine transporters as well as in a primary neuronal cell line model and a dopaminergic neuroblastoma cell line. 4-MTA along with a number of other structurally related amphetamine derivatives and synthetic impurities were found to be cytotoxic to these cells within pharmacologically defined concentrations implying that 4-MTA is a cytotoxic agent in vitro and therefore might have the potential to be a neurotoxic agent in vivo.

Synthesis and serotonin transporter activity of sulphur-substituted alpha-alkyl phenethylamines as a new class of anticancer agents.

The discovery that some serotonin reuptake transporter (SERT) ligands have the potential to act as pro-apoptotic agents in the treatment of cancer adds greatly to their diverse pharmacological application. 4-Methylthioamphetamine (MTA) is a selective ligand for SERT over other monoamine transporters. In this study, a novel library of structurally diverse 4-MTA analogues were synthesised with or without N-alkyl and/or C-alpha methyl or ethyl groups so that their potential SERT-dependent antiproliferative activity could be assessed. Many of the compounds displayed SERT-binding activity as well as cytotoxic activity. While there was no direct correlation between these two effects, a number of derivatives displayed anti-tumour effects in lymphoma, leukaemia and breast cancer cell lines, showing further potential to be developed as possible chemotherapeutic agents.