Translocation of the 5-alkoxy substituent of 2,5-dialkoxyarylalkylamines to the 6-position: effects on 5-HT2A/2C receptor affinity

Positional modification of 2,5-dimethoxyamphetamine analogues has been studied. Specifically, the 5-alkoxy substituent was translocated to the 6-position of the phenyl nucleus. Methoxy groups were also constrained by incorporation into appended dihydrofuran and furan rings. 2,6-Dimethoxy-4-methylamphetamine had an approximately 3-fold lower affinity for the 5-HT2A receptor compared to the parent 2,5-dimethoxy-4-methylamphetamine (DOM). The rigid compound based on the 2,3,5,6-tetrahydrobenzo[1,2-b;5,4-b′]difuran nucleus and the aromatic analogue containing the benzo[1,2-b;5,4-b′]difuran nucleus possessed an approximate 7- and 27-fold increase in affinity, respectively, compared to 2,6-dimethoxy-4-methylamphetamine, the non-rigid, positional isomer.