Norcoclaurine as biosynthetic precursor of thebaine and morphine

Abstract

(R,S)-[1-¹³C]Norcoclaurine and (R,S)-[1-¹³C]coclaurine fed to Papaver somniferum plants afford highly enriched thebaine and morphine which are specifically labelled at position C-9; the results are interpreted as showing that the morphine skeleton is built up from the condensation product of dopamine with 4-hydroxyphenylacetaldehyde.