In order to evaluate the neurobiological mechanism causing the psychogenic effects of methylenedioxy-derivatives of amphetamine,
the carbon-11 labeled analogues of 3,4-methylenedioxymethamphetamine (MDMA),2 and 2,N-dimethyl-4,5-methylenedioxyamphetamine (MADAM-6)4 were prepared for application in in-vivo PET studies by methylation of 3,4-methylenedioxyamphetamine (MDA)1 and 2-methyl-4,5-methylenedioxyamphetamine3 with [11C]CH3I. The radiochemical yield was determined in dependence on time, temperature and amount of precursor. The best conditions
for a fast labeling reaction with carbon-11 on a preparative scale were found to be a reaction time of 10 min using 1 mg of
the corresponding dimethyl-precursors1 or3, thus obtaining radiochemical yields of 60% (based on produced [11C]CH3I). Biodistribution studies were performed in rats, a high brain to blood ratio of 7.5 was observed for [11C]MDMA in contrast to a ratio of 3.7 for [11C]MADAM-6.