General methods for the preparation of deuterium and tritium‐labelled phenethylamines and phenethanollamines: Synthesis of radioactive 6‐hydroxydopamine

Abstract

AbstractA convenient synthetic method for preparation of phenethylamines and phenethanolamines labeled with deuterium or tritium has been developed. A substituted benzaldedyde is condensed with nitromethane or nitroethane and the resultant nitrostyrene is reduced with sodium borotritide or borodeuteride. Subsequent reduction of the nitro‐group and removal of blocking groups yields a phenethylamine or an a‐methylphenethylamine containing a tritium or deuterium in the benzylic position. Condensation of the substituted benzaldehyde with nitromethane or nitroethane at low temperature yields a nitroalcohol which is oxidized to a ketone with Jones reagent. Reduction with sodium borotritide or borodeuteride and subsequent reduation of the nitro‐group and removal of blocking groups yields a phenethanolamine or α‐methylphenethanolamine labeled in the bensylic position. Preparation of deutero‐ and/or tritio‐labeled 2,4,5‐trihydroxyphenethylamine (6‐hydroxydopamine). α‐methyl‐6‐hydroxydopamine, α‐methyl‐p‐tyramine, β‐phenethanolamine. 2‐hydroxyphenethanolamine and α‐methyl‐4‐benzyloxyphenethanolamine is described.